This page has only limited features, please log in for full access.

Unclaimed
M. Zeng
Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China

Basic Info

Basic Info is private.

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 31 July 2021 in Applied Thermal Engineering
Reads 0
Downloads 0

The high concentration of pyrolytic unsaturated hydrocarbons in the near-wall region will generate surface fouling in the regenerative cooling passage, which dramatically deteriorates heat transfer performance. In the present study, the heat and mass transfer processes are investigated by a numerical method to evaluate the mass distribution of pyrolytic products in the near-wall region. A detailed pyrolysis model of RP-3 aviation fuel is incorporated to analyze the pyrolysis process in the regenerative cooling passage. The results indicate that the enhanced heat transfer performance in reacting flow is attributed to the extra heat-absorbing capacity and the flow acceleration caused by the pyrolytic reaction. Besides, because of flow transition and the ultrahigh wall temperature, the near-wall mass fraction of RP-3 decreases first and then increases at the initial heated section. The concentration of products has a transient peak value, which means there is a high risk of carbon deposition at the initial heated section. In addition, the combined influences of flow transition, wall temperature and mass fraction result in the primary reaction rate experiencing three peaks in the near-wall region when the heat flux reaches 2.5 MW/m2.

ACS Style

Ke Tian; Ping Yang; Zicheng Tang; Jin Wang; Min Zeng; Qiuwang Wang. Effect of pyrolytic reaction of supercritical aviation kerosene RP-3 on heat and mass transfer in the near-wall region. Applied Thermal Engineering 2021, 197, 117401 .

AMA Style

Ke Tian, Ping Yang, Zicheng Tang, Jin Wang, Min Zeng, Qiuwang Wang. Effect of pyrolytic reaction of supercritical aviation kerosene RP-3 on heat and mass transfer in the near-wall region. Applied Thermal Engineering. 2021; 197 ():117401.

Chicago/Turabian Style

Ke Tian; Ping Yang; Zicheng Tang; Jin Wang; Min Zeng; Qiuwang Wang. 2021. "Effect of pyrolytic reaction of supercritical aviation kerosene RP-3 on heat and mass transfer in the near-wall region." Applied Thermal Engineering 197, no. : 117401.

Journal article
Published: 21 July 2021 in Energies
Reads 0
Downloads 0

With the rapid development of integrated circuit technology, the heat flux of electronic chips has been sharply improved. Therefore, heat dissipation becomes the key technology for the safety and reliability of the electronic equipment. In addition, the electronic chips are distributed discretely and used periodically in most applications. Based these problems, the characteristics of the heat transfer performance of flow boiling in parallel channels with discrete heat source distribution are investigated by a VOF model. Meanwhile, the two-phase flow instability in parallel channels with discrete heat source distribution is analyzed based on a one-dimensional homogeneous model. The results indicate that the two-phase flow pattern in discrete heat source distribution is more complicated than that in continuous heat source distribution. It is necessary to optimize the relative position of the discrete heat sources, which will affect the heat transfer performance. In addition, compared with the continuous heat source, the flow stability of discrete heat sources is better with higher and lower inlet subcooling. With a constant sum of heating power, the greater the heating power near the outlet, the better the flow stability.

ACS Style

Changming Hu; Rui Wang; Ping Yang; Weihao Ling; Min Zeng; Jiyu Qian; Qiuwang Wang. Numerical Investigation on Two-Phase Flow Heat Transfer Performance and Instability with Discrete Heat Sources in Parallel Channels. Energies 2021, 14, 4408 .

AMA Style

Changming Hu, Rui Wang, Ping Yang, Weihao Ling, Min Zeng, Jiyu Qian, Qiuwang Wang. Numerical Investigation on Two-Phase Flow Heat Transfer Performance and Instability with Discrete Heat Sources in Parallel Channels. Energies. 2021; 14 (15):4408.

Chicago/Turabian Style

Changming Hu; Rui Wang; Ping Yang; Weihao Ling; Min Zeng; Jiyu Qian; Qiuwang Wang. 2021. "Numerical Investigation on Two-Phase Flow Heat Transfer Performance and Instability with Discrete Heat Sources in Parallel Channels." Energies 14, no. 15: 4408.

Original paper
Published: 08 June 2021 in Clean Technologies and Environmental Policy
Reads 0
Downloads 0

Ash deposition in flue gas heat exchanger affects its heat transfer performance and lifecycle, which becomes a crucial factor restricting the efficient recovery and utilization of flue gas waste heat. In this paper, a numerical method was established to investigate the characteristics of ash deposition in tube bundle heat exchangers. An integrated fouling model including transport, rebound, deposition, and removal of particles was employed to predict the behaviour of particles. Then, the effects of particle diameter and flue gas velocity on collision mass, deposition mass, absolute deposition ratio, and relative deposition ratio were studied. At last, the thermal–hydraulic and ash deposition characteristics of three different tube shapes were compared. The results showed that the low-velocity regions on the circumference were the primary locations of particle deposition, and the medium-diameter particles were the main deposition components. With the increase in flue gas velocity, the deposition mass of large-diameter particles decreased, and that of small-diameter particles increased. The use of an elliptical tube and flattened round tube with an apex angle of 60°had also excellent thermal–hydraulic and anti-fouling performances. Consequently, the ash deposition and wear can be reduced by increasing flue gas velocity, filtering medium and large-diameter particles, and using elliptical and flattened round tubes.

ACS Style

Zefeng Guo; Nianqi Li; Jiří Jaromír Klemeš; Qiuwang Wang; Min Zeng. Mechanisms and strategies for ash deposition reduction in flue gas heat exchanger. Clean Technologies and Environmental Policy 2021, 1 -17.

AMA Style

Zefeng Guo, Nianqi Li, Jiří Jaromír Klemeš, Qiuwang Wang, Min Zeng. Mechanisms and strategies for ash deposition reduction in flue gas heat exchanger. Clean Technologies and Environmental Policy. 2021; ():1-17.

Chicago/Turabian Style

Zefeng Guo; Nianqi Li; Jiří Jaromír Klemeš; Qiuwang Wang; Min Zeng. 2021. "Mechanisms and strategies for ash deposition reduction in flue gas heat exchanger." Clean Technologies and Environmental Policy , no. : 1-17.

Original paper
Published: 27 May 2021 in Journal of Biological Physics
Reads 0
Downloads 0

Coronary stents are deployed to treat the coronary artery disease (CAD) by reopening stenotic regions in arteries to restore blood flow, but the risk of the in-stent restenosis (ISR) is high after stent implantation. One of the reasons is that stent implantation induces changes in local hemodynamic environment, so it is of vital importance to study the blood flow in stented arteries. Based on regarding the red blood cell (RBC) as a rigid solid particle and regarding the blood (including RBCs and plasma) as particle suspensions, a non-Newtonian particle suspensions model is proposed to simulate the realistic blood flow in this work. It considers the blood’s flow pattern and non-Newtonian characteristic, the blood cell-cell interactions, and the additional effects owing to the bi-concave shape and rotation of the RBC. Then, it is compared with other four common hemodynamic models (Newtonian single-phase flow model, Newtonian Eulerian two-phase flow model, non-Newtonian single-phase flow model, non-Newtonian Eulerian two-phase flow model), and the comparison results indicate that the models with the non-Newtonian characteristic are more suitable to describe the realistic blood flow. Afterwards, based on the non-Newtonian particle suspensions model, the local hemodynamic environment in stented arteries is investigated. The result shows that the stent strut protrusion into the flow stream would be likely to produce the flow stagnation zone. And the stent implantation can make the pressure gradient distribution uneven. Besides, the wall shear stress (WSS) of the region adjacent to every stent strut is lower than 0.5 Pa, and along the flow direction, the low-WSS zone near the strut behind is larger than that near the front strut. What’s more, in the regions near the struts in the proximal of the stent, the RBC particle stagnation zone is easy to be formed, and the erosion and deposition of RBCs are prone to occur. These hemodynamic analyses illustrate that the risk of ISR is high in the regions adjacent to the struts in the proximal and the distal ends of the stent when compared with struts in other positions of the stent. So the research can provide a suggestion on the stent design, which indicates that the strut structure in these positions of a stent should be optimized further.

ACS Style

Yuchen Wang; Jingmei Zhan; Weiguo Bian; Xiaoli Tang; Min Zeng. Local hemodynamic analysis after coronary stent implantation based on Euler-Lagrange method. Journal of Biological Physics 2021, 47, 143 -170.

AMA Style

Yuchen Wang, Jingmei Zhan, Weiguo Bian, Xiaoli Tang, Min Zeng. Local hemodynamic analysis after coronary stent implantation based on Euler-Lagrange method. Journal of Biological Physics. 2021; 47 (2):143-170.

Chicago/Turabian Style

Yuchen Wang; Jingmei Zhan; Weiguo Bian; Xiaoli Tang; Min Zeng. 2021. "Local hemodynamic analysis after coronary stent implantation based on Euler-Lagrange method." Journal of Biological Physics 47, no. 2: 143-170.

Journal article
Published: 26 May 2021 in Energy
Reads 0
Downloads 0

The present study aims to improve the thermo-chemical conversion behaviours, including reactive transport processes and output performances of an open thermochemical energy storage (TCES) unit. The local thermal non-equilibrium (LTNE) model and the effect of non-uniform porosity are adopted and considered to better elucidate the conversion processes. Cascading the reaction sub-units filled with different thermochemical materials (TCMs), i.e., zeolite, salt hydrate-based composite sorbent, and pure salt of SrBr2·6H2O, to form an integrated storage bed ameliorates the output performance. The numerical results indicate that the maximum temperature difference ranging from 3.5 to 4.9 °C between heat transfer fluid and solid reactants exists during desorption, and the realistic non-uniform porosity facilitates the reactant conversion near the wall compared to the uniform porosity assumption. The cascaded scheme promotes the charging and discharging processes compared to the cases filled with sole TCM, the time required for charging this 10.8 kWh storage model is 16 h. Increasing the charging temperature from 100 °C to 145 °C, the charging time reduced to 6.5 h, saving 59.4%. Boosting the inlet velocity of airflow also accelerates the charging rate. The cascaded storage unit significantly stabilises the output temperature during discharging, warming up the airflow from 20 °C to 35 °C for 24 h with a tiny temperature fluctuation. Airflow with higher relative humidity facilitates hydration but shortens the stable period. Overall power and thermal efficiency of the “thermal accumulator” in charging are 598 W and 92.8%, 164 W and 92.4% in discharging, with a total COP of 0.71. The satisfying performances suggest that the cascaded TCES unit may provide a strategy and reference in the design and promotion of the low-grade energy storage system.

ACS Style

Wei Li; Jiří Jaromír Klemeš; Qiuwang Wang; Min Zeng. Numerical analysis on the improved thermo-chemical behaviour of hierarchical energy materials as a cascaded thermal accumulator. Energy 2021, 232, 120937 .

AMA Style

Wei Li, Jiří Jaromír Klemeš, Qiuwang Wang, Min Zeng. Numerical analysis on the improved thermo-chemical behaviour of hierarchical energy materials as a cascaded thermal accumulator. Energy. 2021; 232 ():120937.

Chicago/Turabian Style

Wei Li; Jiří Jaromír Klemeš; Qiuwang Wang; Min Zeng. 2021. "Numerical analysis on the improved thermo-chemical behaviour of hierarchical energy materials as a cascaded thermal accumulator." Energy 232, no. : 120937.

Journal article
Published: 23 April 2021 in Energy Conversion and Management
Reads 0
Downloads 0

Energy conservation and efficiency improvement are critical problems for industrial process systems. Heat exchanger network retrofit has emerged as a powerful tool for energy-saving and Heat Integration, but the topology modification with new heat exchangers and re-piping is expensive and demands a long payback period. In this study, heat transfer enhancement is deployed in the heat exchanger network retrofit to avoid network topology modification. A target-evaluation method is proposed for heat exchanger network retrofit with the consideration of the thermal efficiency and the level of heat transfer enhancement. Two case studies are conducted to demonstrate the proposed method. The energy-saving of case 1 is 10.6752 MW, which is 13.3% of the original utility loads; 8.0303 MW heat loads are saved in case 2, which is 14.7% of the original utility loads. The results of return on investment indicate that enhancement of the best candidate heat exchanger can bring more energy-saving and better economic efficiency with fewer modifications to the existing heat exchangers, which is also confirmed by sensitivity analysis. The lower temperature effectiveness of the heat exchanger shows great potential for thermal efficiency improvement. The present results highlight the energy-saving effects that heat transfer enhancement has on the heat exchanger network retrofit. The proposed two-stage method supports the further development of energy conservation in different industries.

ACS Style

Nianqi Li; Jinghan Wang; Jiří Jaromír Klemeš; Qiuwang Wang; Petar Sabev Varbanov; Weisheng Yang; Xia Liu; Min Zeng. A target-evaluation method for heat exchanger network optimisation with heat transfer enhancement. Energy Conversion and Management 2021, 238, 114154 .

AMA Style

Nianqi Li, Jinghan Wang, Jiří Jaromír Klemeš, Qiuwang Wang, Petar Sabev Varbanov, Weisheng Yang, Xia Liu, Min Zeng. A target-evaluation method for heat exchanger network optimisation with heat transfer enhancement. Energy Conversion and Management. 2021; 238 ():114154.

Chicago/Turabian Style

Nianqi Li; Jinghan Wang; Jiří Jaromír Klemeš; Qiuwang Wang; Petar Sabev Varbanov; Weisheng Yang; Xia Liu; Min Zeng. 2021. "A target-evaluation method for heat exchanger network optimisation with heat transfer enhancement." Energy Conversion and Management 238, no. : 114154.

Original paper
Published: 15 April 2021 in Clean Technologies and Environmental Policy
Reads 0
Downloads 0

Liquefied natural gas (LNG) is a clean energy source that shows great potential for further development. In the production and transportation process of LNG, heat exchanger is an essential device that conducts the liquefaction and vaporization operations. With the booming development of floating LNG (FLNG) technology, higher requirements have been put forward for heat exchangers due to the limited space and rolling conditions. Printed circuit heat exchanger (PCHE), as a typical micro-channel heat exchanger, is considered an ideal candidate for floating storage and regasification unit (FSRU) due to preeminent compactness and efficiency. In this study, a three-dimensional model of sinusoidal channel-based printed circuit LNG vaporizer is established. The thermal–hydraulic and entropy generation characteristics of the vaporizer with various waviness factors, including the amplitude and wavelength, are numerically investigated. The results indicate that larger amplitude or smaller wavelength results in the heat transfer augmentation with greater pressure drop and minor overall entropy generation. As the secondary flows with boundary layer destructions caused by sinusoidal channel structures enhance the local heat transfer, the entropy generation concentrates at the near-wall region. For a sinusoidal channeled printed circuit LNG vaporizer, moderate amplitude and wavelength are more reasonable to obtain better comprehensive performance, and the thermal–hydraulic performance and irreversible energy loss should be considered simultaneously.

ACS Style

Jinghan Wang; Haoning Shi; Min Zeng; Ting Ma; Qiuwang Wang. Investigations on thermal–hydraulic performance and entropy generation characteristics of sinusoidal channeled printed circuit LNG vaporizer. Clean Technologies and Environmental Policy 2021, 1 -14.

AMA Style

Jinghan Wang, Haoning Shi, Min Zeng, Ting Ma, Qiuwang Wang. Investigations on thermal–hydraulic performance and entropy generation characteristics of sinusoidal channeled printed circuit LNG vaporizer. Clean Technologies and Environmental Policy. 2021; ():1-14.

Chicago/Turabian Style

Jinghan Wang; Haoning Shi; Min Zeng; Ting Ma; Qiuwang Wang. 2021. "Investigations on thermal–hydraulic performance and entropy generation characteristics of sinusoidal channeled printed circuit LNG vaporizer." Clean Technologies and Environmental Policy , no. : 1-14.

Journal article
Published: 06 April 2021 in Chemical Engineering Journal
Reads 0
Downloads 0

Considering the eminent benefits of high energy storage density (ESD) and long-term energy storage ability with ignorable heat losses, thermochemical energy storage (TCES) in salt hydrates is a potential technology to bridge the gap between supply and demand for renewables in domestic heating. The development of thermochemical material is currently the primary concern. In this work, the composite sorbents consisting of expanded graphite (EG) and varying mass ratios of LiOH and LiCl are synthesised and characterised, and the thermochemical behaviours such as sorption kinetics and sorption isotherms are also investigated. The results suggest the salts are uniformly dispersed in the EG matrix in the form of hierarchical micro-nano scale particles, and the salt contents of samples are over 60 wt%, which in favour of the enhancements of vapour sorption property and energy storage density (ESD). By regulating the mass ratio of LiOH and LiCl, the composite sorbents ([email protected]) can achieve thermal upgrade with different temperature requirements, i.e., 35-45℃ for space heating and 45-55℃ for domestic hot water (DHW) production, accompanied by high volumetric ESD (over 200 kWh/m3) benefiting from the reaction enthalpy. Besides that, the effects of regenerative temperature and vapour pressure on the water uptake and ESD of the sorbent are revealed. The cyclability results indicate that more than 95% and 96% of the original ESDs are retained after 20 dehydration-hydration cycles for the samples of [email protected] and [email protected], suggesting good stability of the composites. The developed composite sorbents provide new insights into the fields of long-term energy storage and heat upgrade with high energy density.

ACS Style

Wei Li; Jiří Jaromír Klemeš; Qiuwang Wang; Min Zeng. Characterisation and sorption behaviour of [email protected] composite sorbents for thermochemical energy storage with controllable thermal upgradeability. Chemical Engineering Journal 2021, 421, 129586 .

AMA Style

Wei Li, Jiří Jaromír Klemeš, Qiuwang Wang, Min Zeng. Characterisation and sorption behaviour of [email protected] composite sorbents for thermochemical energy storage with controllable thermal upgradeability. Chemical Engineering Journal. 2021; 421 ():129586.

Chicago/Turabian Style

Wei Li; Jiří Jaromír Klemeš; Qiuwang Wang; Min Zeng. 2021. "Characterisation and sorption behaviour of [email protected] composite sorbents for thermochemical energy storage with controllable thermal upgradeability." Chemical Engineering Journal 421, no. : 129586.

Articles
Published: 22 March 2021 in Heat Transfer Engineering
Reads 0
Downloads 0

This study analyzed the acoustic energy transfer process in expanded pipe of heat exchangers based on the field synergy principle. The synergy between the flow field and the acoustic field was deduced theoretically based on the energy and momentum equations pertaining to the acoustic field. The synergy angle of the flow field and the acoustic field were calculated numerically. The noise propagation process in the expanded pipe was measured experimentally. The results show that the sound pressure level and synergy angle both increases with the increase in flow velocity, whereas the acoustic energy transfer process decreased with the increase in synergy angle. An extended outlet of the expanded pipe segment can reduce the flow noise magnitude with a lower pressure drop. The flow noise can reach 123 dB and the pressure drop is 37.3% and 24.7% less than other cases. In conclusion, the theoretical analysis, experimental tests and numerical simulation method are developed to study the acoustic energy transfer process in segments of expanded pipe based on synergy principle of flow and acoustic fields.

ACS Style

Yiping Cao; Nianqi Li; Hanbin Ke; Min Zeng; Qiuwang Wang. Investigation on the Acoustic Energy Transfer Process in Expanded Pipe of Heat Exchangers. Heat Transfer Engineering 2021, 1 -15.

AMA Style

Yiping Cao, Nianqi Li, Hanbin Ke, Min Zeng, Qiuwang Wang. Investigation on the Acoustic Energy Transfer Process in Expanded Pipe of Heat Exchangers. Heat Transfer Engineering. 2021; ():1-15.

Chicago/Turabian Style

Yiping Cao; Nianqi Li; Hanbin Ke; Min Zeng; Qiuwang Wang. 2021. "Investigation on the Acoustic Energy Transfer Process in Expanded Pipe of Heat Exchangers." Heat Transfer Engineering , no. : 1-15.

Journal article
Published: 10 March 2021 in International Communications in Heat and Mass Transfer
Reads 0
Downloads 0

To further explore the influence law of nanoparticles on the surface tension of stable nano-Lithium Bromide solution (LiBr), the effects of temperature, solution concentration, dispersant and nanoparticles on the surface tension were investigated by Wilhelmy plate method under atmospheric pressure. The results demonstrate that the surface tension ascends with the augmentation of solution concentration and the amount of nanoparticles, decreases with increasing temperature and the amount of dispersant. The surface tension of the solution decreases obviously after adding dispersant. However, there is an optimal value for the amount of dispersant, and the surface tension of solution tends to be gentle increased after exceeding the optimal value of the dispersant, which is 2 wt%. Continue to add nanoparticles, the solution surface tension increases slightly, however, it is still less than pure LiBr. For instance, when the solution temperature is 30 °C and the solution concentration is 50 wt%, the surface tension of nano-LiBr added with 0.01 wt% nanoparticles decreases by 26.20%. The surface tension of nano-LiBr is impacted by coupling of the dispersant and nanoparticles at the same temperature and solution concentration. A surface tension calculation model of nano-LiBr was fitted using experimental data, and the maximum error was 2.78%.

ACS Style

Gang Wang; Peiwen Dong; Yang Lu; Min Zeng; Qunli Zhang. Experimental and theoretical investigation on the surface tension of nano-Lithium Bromide solution. International Communications in Heat and Mass Transfer 2021, 123, 105231 .

AMA Style

Gang Wang, Peiwen Dong, Yang Lu, Min Zeng, Qunli Zhang. Experimental and theoretical investigation on the surface tension of nano-Lithium Bromide solution. International Communications in Heat and Mass Transfer. 2021; 123 ():105231.

Chicago/Turabian Style

Gang Wang; Peiwen Dong; Yang Lu; Min Zeng; Qunli Zhang. 2021. "Experimental and theoretical investigation on the surface tension of nano-Lithium Bromide solution." International Communications in Heat and Mass Transfer 123, no. : 105231.

Journal article
Published: 19 February 2021 in Energies
Reads 0
Downloads 0

As a vital power propulsion device, gas turbines have been widely applied in aircraft. However, fly ash is easily ingested by turbine engines, causing blade abrasion or even film hole blockage. In this study, a three-dimensional turbine cascade model is conducted to analyze particle trajectories at the blade leading edge, under a film-cooled protection. A deposition mechanism, based on the particle sticking model and the particle detachment model, was numerically investigated in this research. Additionally, the invasion efficiency of the AGTB-B1 turbine blade cascade was investigated for the first time. The results indicate that the majority of the impact region is located at the leading edge and on the pressure side. In addition, small particles (1 m and 5 m) hardly impact the blade’s surface, and most of the impacted particles are captured by the blade. With particle size increasing, the impact efficiency increases rapidly, and this value exceeds 400% when the particle size is 50 m. Invasion efficiencies of small particles (1 m and 5 m) are almost zero, and the invasion efficiency approaches 12% when the particle size is 50 m.

ACS Style

Ke Tian; Zicheng Tang; Jin Wang; Milan Vujanović; Min Zeng; Qiuwang Wang. Numerical Investigations of Film Cooling and Particle Impact on the Blade Leading Edge. Energies 2021, 14, 1102 .

AMA Style

Ke Tian, Zicheng Tang, Jin Wang, Milan Vujanović, Min Zeng, Qiuwang Wang. Numerical Investigations of Film Cooling and Particle Impact on the Blade Leading Edge. Energies. 2021; 14 (4):1102.

Chicago/Turabian Style

Ke Tian; Zicheng Tang; Jin Wang; Milan Vujanović; Min Zeng; Qiuwang Wang. 2021. "Numerical Investigations of Film Cooling and Particle Impact on the Blade Leading Edge." Energies 14, no. 4: 1102.

Journal article
Published: 21 November 2020 in Applied Thermal Engineering
Reads 0
Downloads 0

Flow-induced noise and vibration problems of tube bundles in heat-exchangers exist for a long time and often cause severe destruction, performance reduction and large maintenance charge. It is essential to study the flow-induced noise in tube bundles and develop high-efficiency noise elimination measures. The theoretical analysis and numerical simulation method are coupled to compare the aerodynamic noise and heat transfer in shell-and-tube heat exchangers with continuous helical and segmental baffles. The novelty of this paper is to compare the flow-induced noise of tube bundles in shell-and-tube heat-exchangers with continuous helical and segmental baffles. And as an initial trial, this study intends to investigate the aerodynamic noise based on the flow field and acoustic field matching perspective. The results show that the sound pressure, the pressure drop per unit tube length and the Nusselt number all increase with the increase of Reynolds number. And the average synergy angle of continuous helical baffles is 11% lower than that of segmental baffles, which corresponds with 23-37% lower sound pressure.

ACS Style

Yiping Cao; Hanbing Ke; Jiří Jaromír Klemeš; Min Zeng; Qiuwang Wang. Comparison of aerodynamic noise and heat transfer for shell-and-tube heat exchangers with continuous helical and segmental baffles. Applied Thermal Engineering 2020, 185, 116341 .

AMA Style

Yiping Cao, Hanbing Ke, Jiří Jaromír Klemeš, Min Zeng, Qiuwang Wang. Comparison of aerodynamic noise and heat transfer for shell-and-tube heat exchangers with continuous helical and segmental baffles. Applied Thermal Engineering. 2020; 185 ():116341.

Chicago/Turabian Style

Yiping Cao; Hanbing Ke; Jiří Jaromír Klemeš; Min Zeng; Qiuwang Wang. 2020. "Comparison of aerodynamic noise and heat transfer for shell-and-tube heat exchangers with continuous helical and segmental baffles." Applied Thermal Engineering 185, no. : 116341.

Journal article
Published: 04 November 2020 in Journal of Cleaner Production
Reads 0
Downloads 0

With the increasingly energy consumption and environmental degradation, the recovery of low-grade industrial waste heat and the development and utilisation of renewables have become urgent needs. At present, the recovery of waste heat is mainly at high temperature, and the recovery rate of waste heat at medium and low temperatures is low. Adsorption thermochemical energy storage (TCES) is a pivotal technology applied for long-term thermal energy storage based on the reversible gas-solid reaction at mid-to low-temperature. LiOH·H2O is a potential thermochemical material (TCM) candidate because of the high energy storage density (ESD). In this paper, the expanded graphite (EG) is used as supporting matrix to impregnate LiOH to further improve its heat and mass transfer. The water vapour adsorption properties such as sorption capacity and sorption isotherms of the consolidated composite sorbents with EG contents of 0, 5, 8, 12, and 15 wt% were tested. It was found that the samples with 5% and 8% wt% EG have superior sorption capacity and kinetics at various relative humidities (RHs), and the maximum water uptake substantially decreased with increasing temperature. The cyclability results showed 90% and 92% of the original ESDs are retained after 12 cycles for the samples with 8% and 15% wt% EG, suggesting good stability of composite sorbent. The ad/desorption isobars processes also proved the existence of the sorption hysteresis loop, and this phenomenon is more obvious at low pressure. The data fitting results revealed that the kinetics coefficient of the promising composite sorbent containing 8 wt% EG is 0.01671 s – 1 at 30 °C with 58% RH. Compared with the sensible or latent energy storage, the heating temperature produced from the sorbent is adjustable for different purposes. Considering the low emissions and pollution of LiOH-based heat production compared to the coal-fire system, i.e., 1262 kg pollutants are theoretically reduced for a household per year, it is a clean alternative for the residential heat supply.

ACS Style

Wei Li; Jiří Jaromír Klemeš; Qiuwang Wang; Min Zeng. Energy Storage of Low Potential Heat using Lithium Hydroxide Based Sorbent for Domestic Heat Supply. Journal of Cleaner Production 2020, 285, 124907 .

AMA Style

Wei Li, Jiří Jaromír Klemeš, Qiuwang Wang, Min Zeng. Energy Storage of Low Potential Heat using Lithium Hydroxide Based Sorbent for Domestic Heat Supply. Journal of Cleaner Production. 2020; 285 ():124907.

Chicago/Turabian Style

Wei Li; Jiří Jaromír Klemeš; Qiuwang Wang; Min Zeng. 2020. "Energy Storage of Low Potential Heat using Lithium Hydroxide Based Sorbent for Domestic Heat Supply." Journal of Cleaner Production 285, no. : 124907.

Original articles
Published: 19 July 2020 in Numerical Heat Transfer, Part A: Applications
Reads 0
Downloads 0

Non-isothermal melting phenomenon widely exists in phase change process where mixtures are utilized as phase change materials. It is in the mushy zone that phase transition actually occurs during the melting process. Thus, an in-depth understanding of flow and heat transfer in the mushy zone can provide beneficial ways to improve melting technologies. This article focuses on the evolution of mushy zone for low-Prandtl material under Neumann boundary condition. A two-dimensional model composed of liquid zone, mushy zone, and solid zone is established based on the improved enthalpy-porosity method. The pressure and velocity are coupled with SIMPLER algorithm based on the finite volume method with a Fortran code. The results indicate that the temperature on the heating surface is uneven, which are different from the results under Dirac boundary condition. The existence of mushy zone can supply a buffer to the unsteady melting adjacent to the heating surface initially. And the mushy zone experiences expanding stage and shrinking stage. More time is needed for complete melting and the average temperature on the heating surface gets lower under greater melting temperature range. Increasing Ra can result in augmentation of heat transfer in liquid domain and more inclined interface, and the heat transfer is dominated by heat conduction when liquid phase fraction is less than 20%, and thereafter, it is dominated by natural convection. For the same material, increasing heat flux obviously shortens the total melting time. And the mushy zone is reduced for that greater temperature gradient is produced in the mushy area.

ACS Style

Pengbo Zhao; Renkun Dai; Wei Li; Qiuwang Wang; Min Zeng. Modeling the mushy zone during the melting process under Neumann boundary condition using the improved enthalpy-porosity method. Numerical Heat Transfer, Part A: Applications 2020, 78, 1 -20.

AMA Style

Pengbo Zhao, Renkun Dai, Wei Li, Qiuwang Wang, Min Zeng. Modeling the mushy zone during the melting process under Neumann boundary condition using the improved enthalpy-porosity method. Numerical Heat Transfer, Part A: Applications. 2020; 78 (8):1-20.

Chicago/Turabian Style

Pengbo Zhao; Renkun Dai; Wei Li; Qiuwang Wang; Min Zeng. 2020. "Modeling the mushy zone during the melting process under Neumann boundary condition using the improved enthalpy-porosity method." Numerical Heat Transfer, Part A: Applications 78, no. 8: 1-20.

Journal article
Published: 18 July 2020 in Journal of Cleaner Production
Reads 0
Downloads 0

Clean energy storage is of vital importance for cleaner production and environmental protection. This present study focuses on the promotion of clean energy storage efficiency in the widely used shell and tube latent heat thermal energy storage unit. The enhancing effects of fin inside the tube on the charging time and energy storage rate are studied. Numerical investigations are performed through the enthalpy based lattice Boltzmann method couple with curved boundary. Three kinds of configurations for one-fin and two-fin are investigated. Results indicated that fin position can effectively impact the enhancing effects. For one-fin, the maximum difference of the enhanced ratio for different fin positions is 15.17% when Ra = 107, while it is 7.52% for two-fin. The optimal fin position varies with different Ra, but with appropriate approximation, it can be concluded that one-fin on the bottom and two-fin on the vertical direction are the optimal fin position for one-fin and two-fin cases. In addition, one long fin shows better enhancing effects than two short fins. Under the same fin length, the average enhanced ratio for one long fin is 41.82%, while it is only 27.03% for two short fins. These results can provide guidance for the fin configuration in the shell and tube latent heat thermal energy storage unit to achieve higher energy storage efficiency. Since this unit is widely used in various clean energy storage systems, the results would also be beneficial for various industrial applications of clean energy storage and utilization.

ACS Style

Renkun Dai; Javad Mostaghimi; Nianqi Li; Tianrui Deng; Qiuwang Wang; Min Zeng. Charging time and energy storage rate analysis of fin effect inside the horizontal tube for thermal energy storage. Journal of Cleaner Production 2020, 273, 123030 .

AMA Style

Renkun Dai, Javad Mostaghimi, Nianqi Li, Tianrui Deng, Qiuwang Wang, Min Zeng. Charging time and energy storage rate analysis of fin effect inside the horizontal tube for thermal energy storage. Journal of Cleaner Production. 2020; 273 ():123030.

Chicago/Turabian Style

Renkun Dai; Javad Mostaghimi; Nianqi Li; Tianrui Deng; Qiuwang Wang; Min Zeng. 2020. "Charging time and energy storage rate analysis of fin effect inside the horizontal tube for thermal energy storage." Journal of Cleaner Production 273, no. : 123030.

Research article
Published: 07 July 2020 in Langmuir
Reads 0
Downloads 0

Phase change materials (PCMs) are widely used in thermal management and energy storage systems. Investigations on the thermophysical properties enhancement of organic PCMs by introducing carbon-based frameworks have received much attention in recent years. Studies of the phase transition in nanoconfinement are still in controversy with divergent opinions among researchers. In this article, the phase transition behavior of n-eicosane in slit-shaped pores between sheets of graphene is investigated by molecular dynamics simulation. It is found that the graphene interface makes the phase transition temperature of n-eicosane increase, under the initial slit widths of 1.5–5.3 nm. Impacted by interaction and size effects, the distribution and orientation of n-eicosane molecules are quite different from those of the bulk state. In the confinement of graphene, the molecules turn to a reversible layered distribution parallel to the graphene sheets after solidification. The contact layers are found in all the confined systems, which is harder to melt and easier to solidify compared with the main part of the systems. The melting points of different systems are obtained by analysis of the liquid ratio. Finally, the relationship between the dimensionless phase transition point and slit width is discussed.

ACS Style

Xuan Tong; Ping Yang; Min Zeng; Qiuwang Wang. Confinement Effect of Graphene Interface on Phase Transition of n-Eicosane: Molecular Dynamics Simulations. Langmuir 2020, 36, 8422 -8434.

AMA Style

Xuan Tong, Ping Yang, Min Zeng, Qiuwang Wang. Confinement Effect of Graphene Interface on Phase Transition of n-Eicosane: Molecular Dynamics Simulations. Langmuir. 2020; 36 (29):8422-8434.

Chicago/Turabian Style

Xuan Tong; Ping Yang; Min Zeng; Qiuwang Wang. 2020. "Confinement Effect of Graphene Interface on Phase Transition of n-Eicosane: Molecular Dynamics Simulations." Langmuir 36, no. 29: 8422-8434.

Journal article
Published: 24 June 2020 in Applied Energy
Reads 0
Downloads 0

The present study aims to fill the knowledge gap in the partially heated energy storage process by finding the optimal heat source location. A new simplified enthalpy based lattice Boltzmann method is proposed for the present work. The new model follows the predictor–corrector step, while the traditional model follows the collision-streaming step. Compared to the traditional model, this new model has the same accuracy, but it has advantages on virtual memory saving and physical boundary treatment due to its unique structure. Besides, in the partially heated energy storage process, the heat source location can pose significant impact on the charging efficiency and the energy storage rate. The optimal heat source location is where the maximum charging efficiency and energy storage rate are achieved. Results indicate that, a small region with the length of 0.1 l can be deemed as the optimal region for the heat source location, for that the charging time and the energy storage rate at various locations inside that region are almost the same. The optimal region decreases with the increase of Rayleigh and Prandtl numbers. In addition, the optimal regions for some specific heat source lengths and Rayleigh numbers are obtained. Based on these results, a map is provided to indicate the variations of the optimal region. According to this map, the optimal heat source locations for more varied conditions can be estimated through the heat source length and the Rayleigh number, which would be quite useful and significant for the thermal design in various engineering applications.

ACS Style

Renkun Dai; Wei Li; Javad Mostaghimi; Qiuwang Wang; Min Zeng. On the optimal heat source location of partially heated energy storage process using the newly developed simplified enthalpy based lattice Boltzmann method. Applied Energy 2020, 275, 115387 .

AMA Style

Renkun Dai, Wei Li, Javad Mostaghimi, Qiuwang Wang, Min Zeng. On the optimal heat source location of partially heated energy storage process using the newly developed simplified enthalpy based lattice Boltzmann method. Applied Energy. 2020; 275 ():115387.

Chicago/Turabian Style

Renkun Dai; Wei Li; Javad Mostaghimi; Qiuwang Wang; Min Zeng. 2020. "On the optimal heat source location of partially heated energy storage process using the newly developed simplified enthalpy based lattice Boltzmann method." Applied Energy 275, no. : 115387.

Journal article
Published: 15 June 2020 in Journal of Heat Transfer
Reads 0
Downloads 0

Heat transfer characteristics of a circular cylinder in the branch of a T-junction are experimentally investigated in a low-speed wind tunnel with Reynolds number of Rec = 9163. Local and average heat transfer distributions around the circular cylinder are obtained for the cylinder positions from x/Dh=0.5 to 13 and the velocity ratios from 0.117 to 0.614. It is found that the overall heat transfer characteristics in a T-junction duct at high velocity ratio are lower than those at low velocity ratio, and both are higher than those in the straight duct. The local Nusselt number in the T-junction duct is asymmetrical distribution and weakens with increasing velocity ratios and positions of the cylinder. The angles of the front and rear stagnation points in the T-junction duct are the same as those in the straight duct at certain velocity ratio and/or position of the cylinder. However, the angles of the front and rear separation points in the T-junction duct do not match those in the straight duct. Both the heat transfer correlation coefficients and the amplitude ratios increase with increasing positions of the circular cylinder and velocity ratios.

ACS Style

Xiaoyu Wang; Di Qi; Tong Li; Mei Lin; Hanbing Ke; Min Zeng; Qiuwang Wang. Heat Transfer Characteristics of Non-Uniform Flow Around a Circular Cylinder in a T-Junction Duct. Journal of Heat Transfer 2020, 1 .

AMA Style

Xiaoyu Wang, Di Qi, Tong Li, Mei Lin, Hanbing Ke, Min Zeng, Qiuwang Wang. Heat Transfer Characteristics of Non-Uniform Flow Around a Circular Cylinder in a T-Junction Duct. Journal of Heat Transfer. 2020; ():1.

Chicago/Turabian Style

Xiaoyu Wang; Di Qi; Tong Li; Mei Lin; Hanbing Ke; Min Zeng; Qiuwang Wang. 2020. "Heat Transfer Characteristics of Non-Uniform Flow Around a Circular Cylinder in a T-Junction Duct." Journal of Heat Transfer , no. : 1.

Review
Published: 11 June 2020 in Renewable and Sustainable Energy Reviews
Reads 0
Downloads 0

Many methods for enhancing nucleate pool boiling have been proposed to improve the two-phase heat transfer performance in recent years. This article offers a comprehensive comment from published literature in terms of the surface modification of reinforcing heat transfer. Two types of surface modification regarding enhancement of boiling heat transfer coefficient and critical heat flux are categorized for the first time in this paper. The first and most widespread way is artificially changing the characteristics of the surface in advance to improve boiling performance, such as structured surface and surface coating with nanoparticles, namely, the “passive” technology. Oppositely, the “active” one on boiling enhancement seems to have more potential for development and it is favored by some researchers. In brief, the transformation of geometrical shape or characteristics such as wettability spontaneously occurs during boiling, the critical heat flux would thus be delayed. The heat transfer performance, as a result, would be significantly ameliorated. This kind of “smart surface” is usually made up of specific shape memory alloy, polymers, metallic oxides, etc. The mechanisms of boiling enhancement regarding modified surfaces are also reviewed, the capillary wicking, for instance, plays vital role in it. Moreover, various surfaces are presented with emphasis on their advantages/disadvantages. Through the analysis and comparison of the two kinds of modified surfaces, this review also points out some challenges existing in the current studies concerning this topic, such as numerical study, which are worth solving or optimizing to efficiently and economically improve the boiling heat transfer in future.

ACS Style

Wei Li; Renkun Dai; Min Zeng; Qiuwang Wang. Review of two types of surface modification on pool boiling enhancement: Passive and active. Renewable and Sustainable Energy Reviews 2020, 130, 109926 .

AMA Style

Wei Li, Renkun Dai, Min Zeng, Qiuwang Wang. Review of two types of surface modification on pool boiling enhancement: Passive and active. Renewable and Sustainable Energy Reviews. 2020; 130 ():109926.

Chicago/Turabian Style

Wei Li; Renkun Dai; Min Zeng; Qiuwang Wang. 2020. "Review of two types of surface modification on pool boiling enhancement: Passive and active." Renewable and Sustainable Energy Reviews 130, no. : 109926.

Journal article
Published: 10 June 2020 in Energy
Reads 0
Downloads 0

In the present work, the effect of the baffle pattern on the heat transfer and fluid flow characteristics of shell-and-tube heat exchangers are experimentally investigated, including tri-flower baffle, pore plate baffle, rod baffle, segmental & pore baffle and segmental baffle. In order to compare the hydrodynamics and heat transfer characteristics of the five heat exchangers, a water-water heat transfer experiment system is built. Based on the experimental data, and at the same flow rate, comparison with segmental baffle, the hs of tri-flower baffle and pore plate baffle augment 33.8% and 17.7%. The pressure drop of the rod baffle, tri-flower baffle and segmental & pore baffle decrease are 70.1%, 19.5% and 31.1% lower than that of the segmental baffle. The comprehensive performances hs/Δp of the rod baffle, tri-flower baffle and pore plate baffle are all superior to that of the segmental baffle. Finally, the experimental correlative formula is raised for the four heat exchangers, and an optimal design scheme for shell side heat transfer enhancement is proposed.

ACS Style

Jian Chen; Nianqi Li; Yu Ding; Jiří Jaromír Klemeš; Petar Sabev Varbanov; Qiuwang Wang; Min Zeng. Experimental thermal-hydraulic performances of heat exchangers with different baffle patterns. Energy 2020, 205, 118066 .

AMA Style

Jian Chen, Nianqi Li, Yu Ding, Jiří Jaromír Klemeš, Petar Sabev Varbanov, Qiuwang Wang, Min Zeng. Experimental thermal-hydraulic performances of heat exchangers with different baffle patterns. Energy. 2020; 205 ():118066.

Chicago/Turabian Style

Jian Chen; Nianqi Li; Yu Ding; Jiří Jaromír Klemeš; Petar Sabev Varbanov; Qiuwang Wang; Min Zeng. 2020. "Experimental thermal-hydraulic performances of heat exchangers with different baffle patterns." Energy 205, no. : 118066.