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Nadeem Ahmed Sheikh
Department of Mechanical Engineering, Faculty of Engineering & Technology, International Islamic University, Islamabad 44000, Pakistan

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Journal article
Published: 07 June 2021 in Applied Sciences
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Water-in-oil droplets have huge importance in chemical and biotechnology applications, despite their difficulty being produced in microfluidics. Moreover, existing studies focus more on the different shape of microchannels instead of their size, which is one of the critical factors that can influence flow characteristics of the droplets. Therefore, the present work aims to study the behaviours of water-in-oil droplets at the interfacial surface in an offset T-junction microchannel, having different radiuses, using micro-PIV software. Food-grade palm olein and distilled water seeded with polystyrene microspheres particles were used as working fluids, and their captured images showing their generated droplets’ behaviours focused on the junction of the respective microfluidic channel, i.e., radiuses of 400 µm, 500 µm, 750 µm and 1000 µm, were analysed via PIVlab. The increasing in the radius of the offset T-junction microchannel leads to the increase in the cross-sectional area and the decrease in the distilled water phase’s velocity. The experimental velocity of the water droplet is in agreement with theoretical values, having a minimal difference as low as 0.004 mm/s for the case of the microchannel with a radius of 750 µm. In summary, a small increase in the channel’s size yields a significant increase in the overall flow of a liquid.

ACS Style

Hawa Ringkai; Khairul Tamrin; Nadeem Sheikh; Shahrol Mohamaddan. Evolution of Water-in-Oil Droplets in T-Junction Microchannel by Micro-PIV. Applied Sciences 2021, 11, 5289 .

AMA Style

Hawa Ringkai, Khairul Tamrin, Nadeem Sheikh, Shahrol Mohamaddan. Evolution of Water-in-Oil Droplets in T-Junction Microchannel by Micro-PIV. Applied Sciences. 2021; 11 (11):5289.

Chicago/Turabian Style

Hawa Ringkai; Khairul Tamrin; Nadeem Sheikh; Shahrol Mohamaddan. 2021. "Evolution of Water-in-Oil Droplets in T-Junction Microchannel by Micro-PIV." Applied Sciences 11, no. 11: 5289.

Research article
Published: 04 May 2021 in Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering
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Micromixing process in microfluidic devices has been broadly employed in bio-, nano-, and environmental technologies using either miscible or immiscible liquids. However, there are limited experimental studies investigating the mixing process of different densities and viscosities liquids in relation to microfluidics. Therefore, the mixing process of propan-2-ol and water, water and sodium chloride solution, propan-2-ol and sodium chloride solution were experimented and reported at 5 ≤ Re ≤ 50 in T-junction and offset T-junction microchannels. For miscible mixing experiments, i.e. propan-2-ol and water, water and sodium chloride solution, both microchannels show mixing index for each Reynolds number is directly proportional to the mixing time. At low Reynolds number, higher molecular diffusion takes place while at low flow rate, the residence time of fluid is high. The mixing performance is relatively good at high Reynolds number of 40 and 50 due to the significant convection which is caused by the effect of stretching and thinning of liquid lamellae. For immiscible propan-2-ol and sodium chloride solution mixing, offset T-junction microchannel offers better mixing performance than T-junction microchannel at both low and high Reynolds number. The chaotic mixing happened at the intersection of the T-junction microchannel due to the direct interaction of two liquids entering the junction at high momentum.

ACS Style

H Ringkai; Kf Tamrin; Na Sheikh; P Barroy. Characterization of dissimilar liquids mixing in T-junction and offset T-junction microchannels. Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 2021, 1 .

AMA Style

H Ringkai, Kf Tamrin, Na Sheikh, P Barroy. Characterization of dissimilar liquids mixing in T-junction and offset T-junction microchannels. Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering. 2021; ():1.

Chicago/Turabian Style

H Ringkai; Kf Tamrin; Na Sheikh; P Barroy. 2021. "Characterization of dissimilar liquids mixing in T-junction and offset T-junction microchannels." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering , no. : 1.

Journal article
Published: 16 April 2021 in Materials
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This study discloses a method for painting artwork using a CO2 laser. The continuous-wave laser beam, at a predetermined heat flux and a predetermined number of laser beam passes, mixes and displaces the plurality of colored polymer-based compositions, respectively, by way of melting and vaporizing them. Experiments showed a great accuracy of colors and designed patterns between the computer aided design (CAD) drawing and what was achieved after laser discoloration. It was found that lower values of power and speed provide sufficient energy and time to make a melt pool of colors and cause their vaporization from the surface. A detailed numerical simulation was performed to obtain a detailed understanding of the physics of laser interaction with paint using ABAQUS software. The comparative analysis indicated that the top layer of paint (including yellow and green colors) melted upon increasing cutting speed and employing one laser pass. For blue and red paints, two passes of lasers are required; in the case of red color, lower laser speed is also necessary to intensify the heat. This method can be applied for making art designs on each surface color because it is based on melting and vaporization using a laser.

ACS Style

Khairul Tamrin; Kaveh Moghadasi; Marzie Jalil; Nadeem Sheikh; Shahrol Mohamaddan. Laser Discoloration in Acrylic Painting of Visual Art: Experiment and Modeling. Materials 2021, 14, 2009 .

AMA Style

Khairul Tamrin, Kaveh Moghadasi, Marzie Jalil, Nadeem Sheikh, Shahrol Mohamaddan. Laser Discoloration in Acrylic Painting of Visual Art: Experiment and Modeling. Materials. 2021; 14 (8):2009.

Chicago/Turabian Style

Khairul Tamrin; Kaveh Moghadasi; Marzie Jalil; Nadeem Sheikh; Shahrol Mohamaddan. 2021. "Laser Discoloration in Acrylic Painting of Visual Art: Experiment and Modeling." Materials 14, no. 8: 2009.

Research article
Published: 15 April 2021 in Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy
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The optimal performance of dew point indirect evaporative cooler with respect to the operational environment is a challenging task as the same is affected by many parameters. This paper reports the regression modeling and optimization of a counter flow indirect evaporative cooler using the response surface methodology. Experimentation is conducted using the central composite design and regression models are statistically evaluated for adequacy and found within 7% maximum error limit as compared with literature. Results show that supply temperature and cooling capacity increase with increasing inlet air velocity and inlet air temperature. Moreover, dew point and wet bulb effectiveness have a direct relationship with inlet air temperature and an inverse relationship with inlet air velocity. After validation, the regression models are subjected to single-objective and multi-objective optimization based upon the desirability function technique. The multi-objective formulation reveals that optimal performance of the system is achieved at 41.31 °C inlet air temperature, 3.61 m/sec inlet air velocity, 12 g/kg inlet air humidity, and 24.48 °C water temperature. Finally, an operational envelope is proposed to evolve a zone for the best-suited operation of such a device which ensures a reasonable cooling capacity within 1.5 – 2.5 kW while enabling thermal comfort for the conditioned space.

ACS Style

Rubeena Kousar; Muzaffar Ali; Muhammad Kamal Amjad; Nadeem Ahmed Sheikh; Waqas Ahmad. Performance characterization and optimization of counter-flow dew point indirect evaporative cooler through response surface methodology. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 2021, 1 .

AMA Style

Rubeena Kousar, Muzaffar Ali, Muhammad Kamal Amjad, Nadeem Ahmed Sheikh, Waqas Ahmad. Performance characterization and optimization of counter-flow dew point indirect evaporative cooler through response surface methodology. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy. 2021; ():1.

Chicago/Turabian Style

Rubeena Kousar; Muzaffar Ali; Muhammad Kamal Amjad; Nadeem Ahmed Sheikh; Waqas Ahmad. 2021. "Performance characterization and optimization of counter-flow dew point indirect evaporative cooler through response surface methodology." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy , no. : 1.

Journal article
Published: 09 March 2021 in Materials
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Laser-assisted high speed milling is a subtractive machining method that employs a laser to thermally soften a difficult-to-cut material’s surface in order to enhance machinability at a high material removal rate with improved surface finish and tool life. However, this machining with high speed leads to high friction between workpiece and tool, and can result in high temperatures, impairing the surface quality. Use of conventional cutting fluid may not effectively control the heat generation. Besides, vegetable-based cutting fluids are invariably a major source of food insecurity of edible oils which is traditionally used as a staple food in many countries. Thus, the primary objective of this study is to experimentally investigate the effects of water-soluble sago starch-based cutting fluid on surface roughness and tool’s flank wear using response surface methodology (RSM) while machining of 316 stainless steel. In order to observe the comparison, the experiments with same machining parameters are conducted with conventional cutting fluid. The prepared water-soluble sago starch based cutting fluid showed excellent cooling and lubricating performance. Therefore, in comparison to the machining using conventional cutting fluid, a decrease of 48.23% in surface roughness and 38.41% in flank wear were noted using presented approach. Furthermore, using the extreme learning machine (ELM), the obtained data is modeled to predict surface roughness and flank wear and showed good agreement between observations and predictions.

ACS Style

Farhana Yasmin; Khairul Tamrin; Nadeem Sheikh; Pierre Barroy; Abdullah Yassin; Amir Khan; Shahrol Mohamaddan. Laser-Assisted High Speed Machining of 316 Stainless Steel: The Effect of Water-Soluble Sago Starch Based Cutting Fluid on Surface Roughness and Tool Wear. Materials 2021, 14, 1311 .

AMA Style

Farhana Yasmin, Khairul Tamrin, Nadeem Sheikh, Pierre Barroy, Abdullah Yassin, Amir Khan, Shahrol Mohamaddan. Laser-Assisted High Speed Machining of 316 Stainless Steel: The Effect of Water-Soluble Sago Starch Based Cutting Fluid on Surface Roughness and Tool Wear. Materials. 2021; 14 (5):1311.

Chicago/Turabian Style

Farhana Yasmin; Khairul Tamrin; Nadeem Sheikh; Pierre Barroy; Abdullah Yassin; Amir Khan; Shahrol Mohamaddan. 2021. "Laser-Assisted High Speed Machining of 316 Stainless Steel: The Effect of Water-Soluble Sago Starch Based Cutting Fluid on Surface Roughness and Tool Wear." Materials 14, no. 5: 1311.

Journal article
Published: 25 December 2020 in Mathematics
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Water desalination presents a need to address the growing water-energy nexus. In this work, a literature survey is carried out, along an application of a mathematical model is presented to enhance the freshwater productivity rate of a solar-assisted humidification-dehumidification (HDH) type of desalination system. The prime novelty of this work is to recover the waste heat by reusing the feedwater at the exit of the condenser in the brackish water storage tank and to carry out the analysis of its effectiveness in terms of the system’s yearly thermoeconomics. The developed mathematical model for each of the components of the plant is solved through an iterative procedure. In a parametric study, the influence of mass flow rates (MFRs) of inlet air, saline water, feedwater, and air temperature on the freshwater productivity is shown with and without the waste heat recovery from the condensing coil. It is reported that the production rate of water is increased to a maximum of 15% by recovering the waste heat. Furthermore, yearly analysis has shown that the production rate of water is increased to a maximum of 16% for June in the location of Taxila, Pakistan. An analysis is also carried out on the economics of the proposed modification, which shows that the cost per litre of the desalinated water is reduced by ~13%. It is concluded that the water productivity of an HDH solar desalination plant can be significantly increased by recovering the waste heat from the condensing coil.

ACS Style

Rasikh Tariq; Jacinto Torres Jimenez; Nadeem Ahmed Sheikh; Sohail Khan. Mathematical Approach to Improve the Thermoeconomics of a Humidification Dehumidification Solar Desalination System. Mathematics 2020, 9, 33 .

AMA Style

Rasikh Tariq, Jacinto Torres Jimenez, Nadeem Ahmed Sheikh, Sohail Khan. Mathematical Approach to Improve the Thermoeconomics of a Humidification Dehumidification Solar Desalination System. Mathematics. 2020; 9 (1):33.

Chicago/Turabian Style

Rasikh Tariq; Jacinto Torres Jimenez; Nadeem Ahmed Sheikh; Sohail Khan. 2020. "Mathematical Approach to Improve the Thermoeconomics of a Humidification Dehumidification Solar Desalination System." Mathematics 9, no. 1: 33.

Journal article
Published: 23 October 2020 in Journal of Functional Biomaterials
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An accumulating body of evidence reports the synthesis and biomedical applications of silver nanoparticles. However, the studies regarding the use of maleic acid and citric acid in the synthesis of nano-sized silver particles (AgNPs) and micro-sized silver particles (AgMPs) as well as their antibacterial, antifungal, and anticancer activities have not been reported. In the current study, we synthesized AgNPs and AgMPs using maleic acid and citric acid as capping agents and have characterized them by UV-Vis, energy-dispersive X-Ray spectroscopy (EDS), X-Ray diffraction (XRD), and scanning electron microscope (SEM) analysis. The capped silver particles were examined for their antimicrobial activity and cytotoxicity against bacteria, fungi, and brine shrimp. Additionally, the anticancer activity of these particles was tested against human breast and liver cancer cell lines. The free radical scavenging activity of capped silver particles was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. SEM analysis revealed a round plate-like morphology of maleic acid capped particles with an average size of 39 ± 4 nm, whereas citric acid capped particles display flower-shaped morphology with rough surfaces and an average size of 250 ± 5 nm. The uncapped AgMPs were hexagonal with 500 ± 4 nm size. EDS and XRD analysis confirmed the presence of Ag and face-centered cubic crystalline nature, respectively. Functionally, capped silver particles exhibited antibacterial activity against Gram-positive (Staphylococcus aureus, Bacillus subtilis, and Micrococcus luteus) and Gram-negative bacteria (Salmonella setubal, Enterobacter aerogenes, and Agrobacterium tumefaciens). The bactericidal activity was more active against Gram-negative bacteria with minimum inhibitory concentration (MIC) as low as 5 ppm as compared to 25 ppm for Gram-positive. Similarly, the silver particles demonstrated antifungal activity by inhibiting the growth of five fungal strains (Mucor species, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, and Fusarium solani) up to 50% at the concentration of 500 ppm. Additionally, these particles showed substantial toxicity against brine shrimp and also significantly inhibited the proliferation of breast cancer (MCF7) and liver cancer (HePG2) cell lines (IC50 8.9–18.56 µM). Uncapped AgMPs were less effective, inhibiting only the proliferation of MCF7 cells with IC50 46.54 µM. Besides cytotoxicity, these particles acted as potential antioxidants, showing free radical scavenging up to 74.4% in a concentration-dependent manner. Taken together, our results showed that the modifiers affect the shape and size of silver particles and may, in part, contribute to the antimicrobial and antioxidant activity of silver particles. However, the contribution of maleic acid and citric acid in enhancing the antimicrobial, anticancer, and antioxidant potential independent of silver nano and microparticles needs to be studied further. In vivo experiments may determine the therapeutic effectiveness of silver particles capped with these modifiers.

ACS Style

Erum Dilshad; Mehmoona Bibi; Nadeem Ahmed Sheikh; Khairul Fikri Tamrin; Qaisar Mansoor; Qaisar Maqbool; Muhammad Nawaz. Synthesis of Functional Silver Nanoparticles and Microparticles with Modifiers and Evaluation of Their Antimicrobial, Anticancer, and Antioxidant Activity. Journal of Functional Biomaterials 2020, 11, 76 .

AMA Style

Erum Dilshad, Mehmoona Bibi, Nadeem Ahmed Sheikh, Khairul Fikri Tamrin, Qaisar Mansoor, Qaisar Maqbool, Muhammad Nawaz. Synthesis of Functional Silver Nanoparticles and Microparticles with Modifiers and Evaluation of Their Antimicrobial, Anticancer, and Antioxidant Activity. Journal of Functional Biomaterials. 2020; 11 (4):76.

Chicago/Turabian Style

Erum Dilshad; Mehmoona Bibi; Nadeem Ahmed Sheikh; Khairul Fikri Tamrin; Qaisar Mansoor; Qaisar Maqbool; Muhammad Nawaz. 2020. "Synthesis of Functional Silver Nanoparticles and Microparticles with Modifiers and Evaluation of Their Antimicrobial, Anticancer, and Antioxidant Activity." Journal of Functional Biomaterials 11, no. 4: 76.

Journal article
Published: 29 September 2020 in Energies
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This study focused on investigating the bottoming power cycles operating with CO2-based binary mixture, taking into account exergetic, economic and exergo-environmental impact indices. The main intent is to assess the benefits of employing a CO2-based mixture working fluid in closed Brayton bottoming power cycles in comparison with pure CO2 working fluid. Firstly, selection criteria for the choice of suitable additive compound for CO2-based binary mixture is delineated and the composition of the binary mixture is decided based on required cycle minimum temperature. The decided CO2-C7H8 binary mixture with a 0.9 mole fraction of CO2 is analyzed in two cycle configurations: Simple regenerative cycle (SRC) and Partial heating cycle (PHC). Comparative analysis among two configurations with selected working fluid are carried out. Thermodynamic analyses at varying cycle pressure ratio shows that cycle with CO2-C7H8 mixture shows maximum power output and exergy efficiency at rather higher cycle pressure ratio compared to pure CO2 power cycles. PHC with CO2-C7H8 mixture shows 28.68% increment in exergy efficiency with the levelized cost of electricity (LCOE) 21.62% higher than pure CO2 PHC. Whereas, SRC with CO2-C7H8 mixture shows 25.17% increment in exergy efficiency with LCOE 57.14% higher than pure CO2 SRC. Besides showing lower economic value, cycles with a CO2-C7H8 mixture saves larger CO2 emissions and also shows greater exergo-environmental impact improvement and plant sustainability index.

ACS Style

Muhammad Haroon; Nadeem Ahmed Sheikh; Abubakr Ayub; Rasikh Tariq; Farooq Sher; Aklilu Tesfamichael Baheta; Muhammad Imran. Exergetic, Economic and Exergo-Environmental Analysis of Bottoming Power Cycles Operating with CO2-Based Binary Mixture. Energies 2020, 13, 5080 .

AMA Style

Muhammad Haroon, Nadeem Ahmed Sheikh, Abubakr Ayub, Rasikh Tariq, Farooq Sher, Aklilu Tesfamichael Baheta, Muhammad Imran. Exergetic, Economic and Exergo-Environmental Analysis of Bottoming Power Cycles Operating with CO2-Based Binary Mixture. Energies. 2020; 13 (19):5080.

Chicago/Turabian Style

Muhammad Haroon; Nadeem Ahmed Sheikh; Abubakr Ayub; Rasikh Tariq; Farooq Sher; Aklilu Tesfamichael Baheta; Muhammad Imran. 2020. "Exergetic, Economic and Exergo-Environmental Analysis of Bottoming Power Cycles Operating with CO2-Based Binary Mixture." Energies 13, no. 19: 5080.

Book chapter
Published: 09 September 2020 in Renewable Energy - Resources, Challenges and Applications
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This chapter presents an overview of various solar air conditioning technologies such as solar PV, absorption, desiccant, and adsorption cooling systems. It includes feasibility and comparative analysis of numerous standalone and hybrid configurations of solar cooling systems, which were investigated in past. In addition, recent developments in use of solar energy as a regeneration source to dehumidify desiccant wheel in different applications are also discussed. Details of system technologies and climate-based performance comparison in terms of various performance factors, for example, COPth, Qlatent, Qsensible, COPsolar, SF, PES, and Ƞcollector for solar-assisted configurations are highlighted. It is observed that hybridization of solar solid desiccant system results more efficient and cost-effective cooling system as latent and sensible loads are treated independently, especially when regeneration process of desiccant wheel is integrated with solar energy. This review will help to explore further improvements in solar-assisted cooling systems.

ACS Style

Rubeena Kousar; Muzaffar Ali; Nadeem Ahmed Sheikh; Faik Hamad; Muhammad Kamal Amjad. Renewable Energy Application for Solar Air Conditioning. Renewable Energy - Resources, Challenges and Applications 2020, 1 .

AMA Style

Rubeena Kousar, Muzaffar Ali, Nadeem Ahmed Sheikh, Faik Hamad, Muhammad Kamal Amjad. Renewable Energy Application for Solar Air Conditioning. Renewable Energy - Resources, Challenges and Applications. 2020; ():1.

Chicago/Turabian Style

Rubeena Kousar; Muzaffar Ali; Nadeem Ahmed Sheikh; Faik Hamad; Muhammad Kamal Amjad. 2020. "Renewable Energy Application for Solar Air Conditioning." Renewable Energy - Resources, Challenges and Applications , no. : 1.

Journal article
Published: 14 July 2020 in Energies
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A plate fin heat exchanger (PFHE) is a critical part of the cryogenic industry. A plate fin heat exchanger has many applications, but it is commonly used in the liquefied natural gas (LNG) industry for the gasification/liquefaction process. During this gasification to the liquefaction process, there is a large temperature gradient. Due to this large temperature gradient, stresses are produced that directly influence the braze joint of PFHE. Significant work has been carried out on heat transfer and the flow enhancement of PFHE; however, little attention has been paid to structural stability and stresses produced in these brazed joints. Due to these stresses, leakages in PFHE are observed, mostly in braze joints. In the current study, standard fin design is analyzed. In addition, the structural stability of brazed joints under standard conditions is also tested. Two techniques are used here to analyze fins, using the finite element method (FEM), first by examining the whole fin brazed joint on the basis of experimentally calculated yield strength and second by dividing the braze seam into three sections and defining individual strength for each section of the seam to find stress magnitude on the basis of heat-affected zones. Moreover, by using two different techniques to analyze brazed joints, the stresses in the lower face of the brazed joint were increased by 13% and decreased by 18% in the upper face using different zone techniques as compared to standard full braze seam analysis. It can be concluded that different zone techniques are better in predicting stresses as compared to simple full braze seam analysis using the finite element method since stresses along the lower face are more critical.

ACS Style

Mustansar Hayat Saggu; Nadeem Ahmed Sheikh; Usama Muhamad Niazi; Muhammad Irfan; Adam Glowacz; Stanislaw Legutko. Improved Analysis on the Fin Reliability of a Plate Fin Heat Exchanger for Usage in LNG Applications. Energies 2020, 13, 3624 .

AMA Style

Mustansar Hayat Saggu, Nadeem Ahmed Sheikh, Usama Muhamad Niazi, Muhammad Irfan, Adam Glowacz, Stanislaw Legutko. Improved Analysis on the Fin Reliability of a Plate Fin Heat Exchanger for Usage in LNG Applications. Energies. 2020; 13 (14):3624.

Chicago/Turabian Style

Mustansar Hayat Saggu; Nadeem Ahmed Sheikh; Usama Muhamad Niazi; Muhammad Irfan; Adam Glowacz; Stanislaw Legutko. 2020. "Improved Analysis on the Fin Reliability of a Plate Fin Heat Exchanger for Usage in LNG Applications." Energies 13, no. 14: 3624.

Original
Published: 22 June 2020 in Heat and Mass Transfer
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Over the past decade, different variants of desiccant cooling system integrated with direct/indirect evaporative cooler(s) have been simulated and/or analyzed in specific climatic conditions under rather limited operating parameters and for limited durations of time. Complete seasonal and multi-climate performance analyses of solar desiccant cooling system integrated with efficient, indirect Maisotsenko Cycle based evaporative cooler, having combinational installations at process and/or regeneration sides, is rarely investigated and reported. In the current work, multiple configuration variants of solar desiccant cooling system, integrated with multi-stage indirect evaporative cooling technique based on Maisotsenko Cycle, having a designed cooling capacity of 50 kW are analyzed through a model-based transient simulation approach. Simulations are carried out for a complete typical summer season in northern hemisphere, starting from April to September, using TRNSYS in three different climatic zones including subtropical humid summer (Cfa), hot desert (Bwh) and hot semi-arid (Bsh) conditions. The three selected climatic zones cover around 20% of global world map hosting more than 37% of world population. Each configuration is analyzed in terms of wet bulb and dew point effectiveness using their respective cooling techniques, system’s thermal coefficient of performance, and solar fraction for each climate zone. It is seen that the configuration using IEC at both process and regeneration sides has the highest values of coefficient of performance and solar fraction in all selected climatic zones compared to others. The respective values of coefficient of performance is 2.28 and solar fraction of 23.84% observed in Bwh while coefficient of performance of 2.03 and solar fraction of 23.33% in Cfa; and coefficient of performance of 2.12 and solar fraction of 46.86% in Bsh climatic zones are noted. The increase of solar fraction in hot and arid climates are expected compared to Cfa. While the value of coefficient of performance for such a system is significantly improved and shows promising prospects to efficiently provide thermal comfort during summer seasons.

ACS Style

Waqas Ahmad; Muzaffar Ali; Nadeem Ahmed Sheikh; Javed Akhtar. Effect of efficient multi-stage indirect evaporative cooling on performance of solar assisted desiccant air conditioning in different climatic zones. Heat and Mass Transfer 2020, 56, 1 -17.

AMA Style

Waqas Ahmad, Muzaffar Ali, Nadeem Ahmed Sheikh, Javed Akhtar. Effect of efficient multi-stage indirect evaporative cooling on performance of solar assisted desiccant air conditioning in different climatic zones. Heat and Mass Transfer. 2020; 56 (9):1-17.

Chicago/Turabian Style

Waqas Ahmad; Muzaffar Ali; Nadeem Ahmed Sheikh; Javed Akhtar. 2020. "Effect of efficient multi-stage indirect evaporative cooling on performance of solar assisted desiccant air conditioning in different climatic zones." Heat and Mass Transfer 56, no. 9: 1-17.

Journal article
Published: 01 May 2020 in Energies
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Liquefied natural gas (LNG) is one of the hydrocarbon fuels with the least carbon footprint having a rapidly rising global share in the prime energy market. LNG processing for transportation at longer distances works under cryogenic conditions, especially when used for liquefaction and gasification applications. The supply chain of the eco-environmental friendly hydrocarbon is heavily dependent on the processing plant used for liquefaction and subsequent re-gasification of the natural gas. Plate-fin heat exchangers are extensively used in the LNG industry for both re-gasification as well as liquefaction processes. The exchange of heat during the process of natural gas phase change involves plate-fin heat exchangers working under cryogenic low-temperature conditions. The heat exchangers are designed to have brazed joints that are most vulnerable to failure under these temperature conditions. One failure of such a joint can not only hinder the supply chain but also may result in fire and life hazards. In almost all earlier studies, analytical and numerical methods were used to analyze these braze joints using finite element method methods and examining the stresses while keeping them at or near to ambient conditions. In this research, the plate-fin heat exchanger is investigated for its structural stability of brazed fins for three different fin configurations: plain, wavy and compound having different joint geometries. In addition, the analyses are carried out using experimentally measured brazed joint strength which is measured to be on average 22% lower than the base material strength owing to brazing process and resultant heat-affected zone (HAZ). Therefore, the reliability is assessed for these joints in terms of factor of safety (FOS) while keeping in view the actual yield criteria. It was found that the structural stability of compound fins configuration is weakest amongst all considered fin configurations. The failure of the compound fin brazed joint is expected to be along the horizontal path of the joint due to yielding. The study also predicts the life of the fin brazed joints in different joining directions with different topologies of fins commonly recommended in the literature. It is observed that the commonly recommended safe fin geometries are predicted to be susceptible to failure if a reduction in the brazed joint is considered. The analysis and recommendation in this paper shall provide a reliable and safe design approach for plate-fin exchangers for different operating conditions especially in low to cryogenic temperature applications.

ACS Style

Mustansar Hayat Saggu; Nadeem Ahmed Sheikh; Usama Muhammad Niazi; Muhammad Irfan; Adam Glowacz. Predicting the Structural Reliability of LNG Processing Plate-Fin Heat Exchanger for Energy Conservation. Energies 2020, 13, 2175 .

AMA Style

Mustansar Hayat Saggu, Nadeem Ahmed Sheikh, Usama Muhammad Niazi, Muhammad Irfan, Adam Glowacz. Predicting the Structural Reliability of LNG Processing Plate-Fin Heat Exchanger for Energy Conservation. Energies. 2020; 13 (9):2175.

Chicago/Turabian Style

Mustansar Hayat Saggu; Nadeem Ahmed Sheikh; Usama Muhammad Niazi; Muhammad Irfan; Adam Glowacz. 2020. "Predicting the Structural Reliability of LNG Processing Plate-Fin Heat Exchanger for Energy Conservation." Energies 13, no. 9: 2175.

Journal article
Published: 23 April 2020 in Applied Thermal Engineering
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In the current work, an experimental analysis of a solar-assisted desiccant based heating and humidification system is performed for winter season under actual cold and dry conditions of Taxila, Pakistan. The installed setup consists of a silica-gel based desiccant wheel, a heat wheel, dual collector field of flat plate and evacuated tube collectors, and insulated storage tank. The day long measurements and assessments are reported during the months of December to February. The selected months represent wide range of cold and dry weather conditions which are applicable to different climate zones. The experimental results revealed that on average the system heating capacity, COPth, COPe, and auxiliary thermal power requirements for heating are around 5.9 kW, 1.48, 2.14 and 2.75 kW, respectively. Moreover, the solar fraction and the thermal efficiency of collector arrays are observed to be 64.75% and 40%, respectively. The uncertainties associated with humidification effectiveness, heating capacity and COPth are ±2.1%, ±5.5%, and ±7%, respectively. Finally, heating seasonal performance factor of 5 Btu/Wh is achieved. Based on the assessments, it is noted that the solar-assisted heating and humidification system is a viable solution for operation in cold and dry conditions.

ACS Style

Aizaz Kashif; Muzaffar Ali; Nadeem Ahmed Sheikh; Vladimir Vukovic; M. Shehryar. Experimental analysis of a solar assisted desiccant-based space heating and humidification system for cold and dry climates. Applied Thermal Engineering 2020, 175, 115371 .

AMA Style

Aizaz Kashif, Muzaffar Ali, Nadeem Ahmed Sheikh, Vladimir Vukovic, M. Shehryar. Experimental analysis of a solar assisted desiccant-based space heating and humidification system for cold and dry climates. Applied Thermal Engineering. 2020; 175 ():115371.

Chicago/Turabian Style

Aizaz Kashif; Muzaffar Ali; Nadeem Ahmed Sheikh; Vladimir Vukovic; M. Shehryar. 2020. "Experimental analysis of a solar assisted desiccant-based space heating and humidification system for cold and dry climates." Applied Thermal Engineering 175, no. : 115371.

Article
Published: 21 February 2020 in International Journal of Thermophysics
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In this work, an empirical correlation to predict the thermal conductivity of CuO-water nanofluid is developed. The prime novelty of this work is to include the size of the nanoparticles and to utilize the techniques of artificial intelligence on this problem. The experimentation is carried out for the following operating range: working temperature between 302 K to 323 K, particle volume fraction between 0.1 % and 0.4 %, and a particle diameter of 40 nm and 80 nm. The results of the experimentation are benchmarked with the standard properties of water. Afterwards, three different data-driven techniques (SRM, GMDH and ANN) are applied for the correlation development of thermal conductivity. It is reported that GMDH of third polynomial power is the most appropriate yielding an R2 of 0.99973, SSE of 2.208834e−06, and MSE of 1.004e−08. Extensive external validation is also carried out on these techniques to ensure the correctness of the methodology. The results of these surrogate models are compared with other models based on their performance indices of regression. Another comparative study has shown that the prediction capability of our proposed regression model has a minimum deviation of ~ 0.35 % and a maximum deviation of ~ 3.7 %.

ACS Style

Rasikh Tariq; Yasir Hussain; Nadeem Sheikh; Kamran Afaq; Hafiz Muhammad Ali. Regression-Based Empirical Modeling of Thermal Conductivity of CuO-Water Nanofluid using Data-Driven Techniques. International Journal of Thermophysics 2020, 41, 1 -28.

AMA Style

Rasikh Tariq, Yasir Hussain, Nadeem Sheikh, Kamran Afaq, Hafiz Muhammad Ali. Regression-Based Empirical Modeling of Thermal Conductivity of CuO-Water Nanofluid using Data-Driven Techniques. International Journal of Thermophysics. 2020; 41 (4):1-28.

Chicago/Turabian Style

Rasikh Tariq; Yasir Hussain; Nadeem Sheikh; Kamran Afaq; Hafiz Muhammad Ali. 2020. "Regression-Based Empirical Modeling of Thermal Conductivity of CuO-Water Nanofluid using Data-Driven Techniques." International Journal of Thermophysics 41, no. 4: 1-28.

Journal article
Published: 25 March 2019 in International Journal of Heat and Mass Transfer
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Numerical analysis is carried out to investigate the effect of an upstream gust-impulse on the transient fluid flow and associated convective heat transfer from a two dimensional rotationally oscillating circular cylinder. Three distinct oscillation scenarios based on the oscillation amplitude are investigated. Forcing frequency for each rotational amplitude is varied such that the system remains within the lock-on state. Further, three different gust scenarios are chosen by relating the gust frequency, StG, to the natural vortex shedding frequency in the streamlined flow for a fixed Reynolds number of 110 at Prandtl number of 7. Balances for mass, momentum, and energy are solved by considering incompressible, viscous fluid subjected to no-slip CWT boundary at the cylinder wall. Phase diagrams, the spatiotemporal mean of the pressure coefficient and Nusselt number i.e. CP‾‾ and Nu‾‾, and vorticity and temperature contours are presented and discussed in detail. Temporal evolution of lift coefficient (CL) and Lissajous curves of lift coefficient against drag coefficient depict the perturbing effect of the gust-impulse. Time averaged drag coefficient (CD‾) and RMS values of lift coefficient (CL-RMS) show contrasting shifts in their peak values as the rotational-oscillation amplitude is increased. In addition to causing a transient phase difference between the cylinder angular velocity and the lift coefficient, introduction of the gust-impulse in the flow domain induces secondary frequencies causing transient amplification of the lift force which tends to make the system temporarily unstable by shifting it out of the lock-on state. The induced phase difference causes short term shear layer stretching and early vortex detachment around the cylinder surface thereby affecting the overall flow and the resultant convective heat transfer physics in the system. Moreover, a regression correlation is presented relating the oscillation amplitude, oscillation forcing Strouhal frequency and gust Strouhal frequency to the spatiotemporal averaged Nusselt number.

ACS Style

Arsalan Yawar; M. Ebrahem; S. Manzoor; Nadeem Sheikh; Muzaffar Ali. Transient cross flow and heat transfer over a rotationally oscillating cylinder subjected to gust impulse. International Journal of Heat and Mass Transfer 2019, 137, 108 -123.

AMA Style

Arsalan Yawar, M. Ebrahem, S. Manzoor, Nadeem Sheikh, Muzaffar Ali. Transient cross flow and heat transfer over a rotationally oscillating cylinder subjected to gust impulse. International Journal of Heat and Mass Transfer. 2019; 137 ():108-123.

Chicago/Turabian Style

Arsalan Yawar; M. Ebrahem; S. Manzoor; Nadeem Sheikh; Muzaffar Ali. 2019. "Transient cross flow and heat transfer over a rotationally oscillating cylinder subjected to gust impulse." International Journal of Heat and Mass Transfer 137, no. : 108-123.

Journal article
Published: 27 January 2019 in Building and Environment
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In this work, an opportunity to improve the seasonal utilizability of an indirect evaporative cooler integrated air-conditioning system is presented. The improved design recovers the waste heat from wet air passages by supplying them to the comfort zone of produce commodities whilst supplying the dry air to human-occupants-comfort-zone i.e. operating for dual purposes. The analysis is carried out for three different configurations of indirect evaporative cooler namely counter-arrangement, cross-arrangement, and multi-zonal (advanced) heat and mass exchanging devices. The performance of each integrated air-conditioning system is presented in terms of a ‘special’ mixing ratio, system capacity, and energy-efficiency-ratio. Results have shown that the waste heat from the wet passages can be exploited and the seasonal utilizability factors of the proposed air-conditioning system can reach up to 1.41, 1.13 and 1.34 for counter, cross, and multi-zonal indirect-evaporative coolers respectively. Afterwards, the system analysis for different climatic conditions has shown that it offers high performance in desert and semi-arid regions.

ACS Style

Rasikh Tariq; Nadeem Sheikh; J. Xamán; A. Bassam. Recovering waste energy in an indirect evaporative cooler – A case for combined space air conditioning for human occupants and produce commodities. Building and Environment 2019, 152, 105 -121.

AMA Style

Rasikh Tariq, Nadeem Sheikh, J. Xamán, A. Bassam. Recovering waste energy in an indirect evaporative cooler – A case for combined space air conditioning for human occupants and produce commodities. Building and Environment. 2019; 152 ():105-121.

Chicago/Turabian Style

Rasikh Tariq; Nadeem Sheikh; J. Xamán; A. Bassam. 2019. "Recovering waste energy in an indirect evaporative cooler – A case for combined space air conditioning for human occupants and produce commodities." Building and Environment 152, no. : 105-121.

Original
Published: 27 November 2018 in Heat and Mass Transfer
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Maisotsenko Humid Air Bottoming Cycle (MHABC) is a viable option for the waste heat recovery of gas turbine topping cycle to attain a higher efficiency point of the combined cycle power plant; thus, having a potential of lower CO2 emissions towards environment. In this work, instead of the typically proposed counter flow configuration of the air saturator, a novel mixed flow configuration is proposed. The proposed configuration uses a hybrid cross-flow and a regenerative counter-flow heat and mass exchanger (HMX). This hybrid HMX is numerically simulated to estimate optimal amount of saturated air which can lead to maximum efficiency and power output. The mathematical model of the mixed flow configuration HMX based air saturator is developed by applying mass and energy balance laws on a selected control volume. The results of the air saturator are initially validated using previously published experimental data for air cooling applications. Furthermore, simulations for high-pressure operations suitable for power generation are performed and a parametric analysis shows that optimal mass flow rate ratio between the working air in the dry channel and incoming air for cross-flow part is 0.65. Optimal mass flow ratio between the working air wet channel and working air dry channel for the counter-flow part is 0.5. The integration of hybrid air saturator in MHABC can yield a maximum of ~57 MW of output work and ~42% of thermal efficiency. The proposed system can achieve a 7% increment in total output work, and 9% increment in thermal efficiency as compared to the counter-flow configuration as an air saturator in the bottoming cycle. Furthermore, the proposed system has ~55% fewer carbon footprint as compared to counter-flow configuration alone as an air saturator.

ACS Style

Rasikh Tariq; Nadeem Ahmed Sheikh; A. Bassam; J. Xamán. Analysis of Maisotsenko humid air bottoming cycle employing mixed flow air saturator. Heat and Mass Transfer 2018, 55, 1477 -1489.

AMA Style

Rasikh Tariq, Nadeem Ahmed Sheikh, A. Bassam, J. Xamán. Analysis of Maisotsenko humid air bottoming cycle employing mixed flow air saturator. Heat and Mass Transfer. 2018; 55 (5):1477-1489.

Chicago/Turabian Style

Rasikh Tariq; Nadeem Ahmed Sheikh; A. Bassam; J. Xamán. 2018. "Analysis of Maisotsenko humid air bottoming cycle employing mixed flow air saturator." Heat and Mass Transfer 55, no. 5: 1477-1489.

Journal article
Published: 01 November 2018 in International Journal of Heat and Mass Transfer
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Numerical results are presented investigating the effect of a gust impulse on the transient fluid flow and forced convection heat transfer from a rotating circular cylinder near a plane boundary in the two-dimensional, in-compressible flow regime. Reynolds numbers of 200, 600 and 1000 have been studied for a fluid of Prandtl number 7. Starting from static, the steady non-dimensional rotation rate is varied up to a maximum value of 5.5, in the counter clockwise direction, such that (α∈{0,0.5,1,2,2.5,4.7,4.9,5,5.5})(α∈{0,0.5,1,2,2.5,4.7,4.9,5,5.5}). Gap to diameter ratio for this work is fixed at 3. Typical governing equations namely continuity, momentum and energy have been solved using the Constant Wall Temperature (CWT) boundary condition. This work notes that higher rotation rate of the circular cylinder, in the second vortex shedding regime and slight perturbations in the flow may cause a resultant effect which leads to short term disruption in the plane wall boundary layer dynamics even at larger values of gap to diameter ratio. Moreover, the gust impulse superimposed to the mean flow at the domain inlet causes creation of temporary convection zones in the cylinder wake which have significant impact on the heat transfer from the cylinder surface. Variations in Strouhal number, vorticity contours, peak vorticity trajectory plots, temperature contours and Nusselt number distribution are presented and discussed in comparison with the existing literature.

ACS Style

Rabia Hanif; O.G. Bhatti; M. Ebrahem; S. Manzoor; Muzaffar Ali; Nadeem Sheikh. Transient fluid flow and heat transfer over a rotating circular cylinder near a wall subject to a single gust impulse. International Journal of Heat and Mass Transfer 2018, 126, 1178 -1193.

AMA Style

Rabia Hanif, O.G. Bhatti, M. Ebrahem, S. Manzoor, Muzaffar Ali, Nadeem Sheikh. Transient fluid flow and heat transfer over a rotating circular cylinder near a wall subject to a single gust impulse. International Journal of Heat and Mass Transfer. 2018; 126 ():1178-1193.

Chicago/Turabian Style

Rabia Hanif; O.G. Bhatti; M. Ebrahem; S. Manzoor; Muzaffar Ali; Nadeem Sheikh. 2018. "Transient fluid flow and heat transfer over a rotating circular cylinder near a wall subject to a single gust impulse." International Journal of Heat and Mass Transfer 126, no. : 1178-1193.

Journal article
Published: 05 October 2018 in Energies
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The incorporation of a Maisotsenko (M) Cycle into an indirect evaporative cooler has led to the achievement of sub-wet bulb temperature without any humidification, thus making it a possible green and sustainable alternative for handling the cooling load of a building. In this work, the thermal performance of a cross-flow heat and mass exchanger (HMX) is enhanced by the addition of nanoparticles in the wet channel because they significantly influence the heat and mass transfer characteristics of the base fluid. A governing model for the temperature and humidity variations of the HMX is numerically simulated. Initial benchmarking is achieved using water properties. Afterward, a comparative study is conducted using aluminum-oxide-, copper-oxide-, and titanium-oxide-based nanofluids. Enhancements of 24.2% in heat flux, 19.24% in wet bulb effectiveness, 7.04% in dew point effectiveness, 29.66% in cooling capacity, and 28.43% in energy efficiency ratio are observed by using alumina-based nanofluid as compared to water in the wet channel of the cross-flow HMX. Furthermore, a particle volume concentration of 1% and a particle diameter of 20nm are recommended for maximum performance.

ACS Style

Rasikh Tariq; Changhong Zhan; Nadeem Ahmed Sheikh; Xudong Zhao. Thermal Performance Enhancement of a Cross-Flow-Type Maisotsenko Heat and Mass Exchanger Using Various Nanofluids. Energies 2018, 11, 2656 .

AMA Style

Rasikh Tariq, Changhong Zhan, Nadeem Ahmed Sheikh, Xudong Zhao. Thermal Performance Enhancement of a Cross-Flow-Type Maisotsenko Heat and Mass Exchanger Using Various Nanofluids. Energies. 2018; 11 (10):2656.

Chicago/Turabian Style

Rasikh Tariq; Changhong Zhan; Nadeem Ahmed Sheikh; Xudong Zhao. 2018. "Thermal Performance Enhancement of a Cross-Flow-Type Maisotsenko Heat and Mass Exchanger Using Various Nanofluids." Energies 11, no. 10: 2656.

Journal article
Published: 06 July 2018 in Applied Energy
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In this work, an innovative and novel integrated Maisotsenko cycle-based air saturator is proposed as a humidifier in humidification-dehumidification type desalination system. The proposed system has unique flow characteristic within the heat and mass exchanger to maximize air saturation at the exit of humidifier; thus, maximizing the potential for desalination. The process of air saturation in the wet channel is altered by including an infiltration flow from the dry passes on to the wet passes of the air saturator. A detailed mathematical model is developed and solved through an iterative procedure, and the performance of the system is deduced based on fresh water production rate, recovery ratio, and gain-output-ratio. It is reported that in the proposed design an infiltration rate of 0.6 corresponds to maximum water evaporation rate and justified pump and blower work. Comparative analysis has shown that the proposed novel system configuration offers 30% higher fresh water productivity, 46% higher recovery ratio, and 11% higher gain-output-ratio as compared to conventional direct-contact humidifier-based desalination plant. Performance investigation analysis is carried out for 31 different cities of the world to determine the applicability of the proposed system under different climatic conditions. Economic estimation has shown that the cost of desalinated water using proposed system is 0.030 USD/liter which is 14% lower than the conventional humidification-dehumidification desalination system. Furthermore, environmental analysis has shown that the proposed system has ∼7% lower carbon footprints. It is concluded that the proposed system offers energy-efficient, cost-effective and environmental friendly method of desalination and can be used in most parts of the world.

ACS Style

Rasikh Tariq; Nadeem Sheikh; J. Xamán; A. Bassam. An innovative air saturator for humidification-dehumidification desalination application. Applied Energy 2018, 228, 789 -807.

AMA Style

Rasikh Tariq, Nadeem Sheikh, J. Xamán, A. Bassam. An innovative air saturator for humidification-dehumidification desalination application. Applied Energy. 2018; 228 ():789-807.

Chicago/Turabian Style

Rasikh Tariq; Nadeem Sheikh; J. Xamán; A. Bassam. 2018. "An innovative air saturator for humidification-dehumidification desalination application." Applied Energy 228, no. : 789-807.