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This article reports the results of a study into the effect of operating parameters on the occurrence and course of gas–liquid two-phase phenomena during the fogging process carried out with the use of a conical pressure-swirl nozzle. Four alternatives of the stub regulation angles and four values of pressure of air supply to the nozzle were tested as part of the current research. The range of the investigated variables was common for the operation of fumigators used to prevent the spread of SARS-CoV-2 virus. The liquid flow rate (weighting method), the field of velocity, and turbulent flow intensity factor, as well as velocity profiles over the section of 1 m from the nozzle were determined using the particle image velocimetry (PIV) technique. The obtained results were correlated with the measurements of the diameters of spray droplets using the laser light scattering (LLS) technique. On the basis of this research, a dependence between the nozzle parameters and the spray cone pattern was identified in terms of dynamics and droplet diameter distribution. As a result of the research, a wide range of parameters were identified in which the fogging process was carried out in a stable and repeatable manner. There were exceptions to this rule only in the cases when there was a deficiency of the liquid necessary to generate a two-phase mixture.
Waldemar Fedak; Roman Ulbrich; Grzegorz Ligus; Marek Wasilewski; Szymon Kołodziej; Barbara Wasilewska; Marek Ochowiak; Sylwia Włodarczak; Andżelika Krupińska; Ivan Pavlenko. Influence of Spray Nozzle Operating Parameters on the Fogging Process Implemented to Prevent the Spread of SARS-CoV-2 Virus. Energies 2021, 14, 4280 .
AMA StyleWaldemar Fedak, Roman Ulbrich, Grzegorz Ligus, Marek Wasilewski, Szymon Kołodziej, Barbara Wasilewska, Marek Ochowiak, Sylwia Włodarczak, Andżelika Krupińska, Ivan Pavlenko. Influence of Spray Nozzle Operating Parameters on the Fogging Process Implemented to Prevent the Spread of SARS-CoV-2 Virus. Energies. 2021; 14 (14):4280.
Chicago/Turabian StyleWaldemar Fedak; Roman Ulbrich; Grzegorz Ligus; Marek Wasilewski; Szymon Kołodziej; Barbara Wasilewska; Marek Ochowiak; Sylwia Włodarczak; Andżelika Krupińska; Ivan Pavlenko. 2021. "Influence of Spray Nozzle Operating Parameters on the Fogging Process Implemented to Prevent the Spread of SARS-CoV-2 Virus." Energies 14, no. 14: 4280.
The study explored areas related to the effect of installing an additional element in the axis of the cyclone separator (in the form of a rod with a circular cross-section) on its performance. 30 geometrical variants (the variable parameters included rod diameter and length) were used for this purpose. The research was carried out using three methods – CFD (based on LES and DPM models), experimental research and stereo-PIV. The use of three research methods made it possible to conduct the process of validating the results. The placement of a rod with a circular cross-section on the axis of the cyclone separator significantly improved its performance (overall separation efficiency, Stk50 and Eu). The most beneficial variant led to an increase in the overall separation efficiency by 8.2% and a reduction in Stk50 by 25.5%. In the case of a pressure drop (expressed as Eu), all variants generated a lower value of Eu than the base variant - the maximum reduction observed was 23.9% (as compared to the base model). Additionally, to comprehensively study the effect of using an additional element on the flow field, the mean and fluctuating velocity and pressure fields were analyzed for individual variants and compared with the standard geometry. Furthermore, it was observed that the use of a rod stabilized the flow in the region confined to the inner vortex, increased the symmetry of the flow, and improved the performance of cyclone separators.
Marek Wasilewski; Lakhbir Singh Brar; Grzegorz Ligus. Effect of the central rod dimensions on the performance of cyclone separators - optimization study. Separation and Purification Technology 2021, 274, 119020 .
AMA StyleMarek Wasilewski, Lakhbir Singh Brar, Grzegorz Ligus. Effect of the central rod dimensions on the performance of cyclone separators - optimization study. Separation and Purification Technology. 2021; 274 ():119020.
Chicago/Turabian StyleMarek Wasilewski; Lakhbir Singh Brar; Grzegorz Ligus. 2021. "Effect of the central rod dimensions on the performance of cyclone separators - optimization study." Separation and Purification Technology 274, no. : 119020.
The paper presents the results of research on liquid flow maldistribution in the shell side of a shell-and-tube heat exchanger (STHE). This phenomenon constitutes the reason for the formation of the velocity reduction area and adversely affects heat transfer and pressure drop. In order to provide details of the liquid distribution in STHE, two visualization methods were utilized. First, computational fluid dynamics (CFD) code coupled with the k-ε model and the laser-based particle image velocimetry (PIV) technique was applied. The tests were carried out for a bundle comprising 37 tubes in an in-line layout with a pitch dz/t = 1.5, placed in a shell with Din = 0.1 m. The STHE liquid feed rates corresponded to Reynolds numbers Rein equal to 16,662, 24,993, and 33,324. The analysis demonstrated that the flow maldistribution in the investigated geometry originates the result of three main streams in the cross-section of the shell side: central stream, oblique stream, and bypass stream. For central and oblique streams, the largest velocity reduction areas were formed in the wake of the tubes. On the basis of the flow visualization, it was also shown that the in-line layout of the tube bundle helps to boost the wake region between successive tubes in a row. Additionally, unfavorable vortex phenomena between the last row of tubes and the lower part of the exchanger shell were identified in the investigations. The conducted studies confirmed the feasibility of both methods in the identification and assessment of fluid flow irregularities in STHE. The maximum error of the CFD method in comparison to the experimental methods did not exceed 7% in terms of the pressure drops and 11% in the range of the maximum velocities.
Grzegorz Ligus; Marek Wasilewski; Szymon Kołodziej; Daniel Zając. CFD and PIV Investigation of a Liquid Flow Maldistribution across a Tube Bundle in the Shell-and-Tube Heat Exchanger with Segmental Baffles. Energies 2020, 13, 5150 .
AMA StyleGrzegorz Ligus, Marek Wasilewski, Szymon Kołodziej, Daniel Zając. CFD and PIV Investigation of a Liquid Flow Maldistribution across a Tube Bundle in the Shell-and-Tube Heat Exchanger with Segmental Baffles. Energies. 2020; 13 (19):5150.
Chicago/Turabian StyleGrzegorz Ligus; Marek Wasilewski; Szymon Kołodziej; Daniel Zając. 2020. "CFD and PIV Investigation of a Liquid Flow Maldistribution across a Tube Bundle in the Shell-and-Tube Heat Exchanger with Segmental Baffles." Energies 13, no. 19: 5150.
This paper focuses on evaluation of differences in the newly manufactured U-tubes and ones after operation. Differences in geometry and internal surface roughness were investigated and a flow simulation was carried out in the Ansys Fluent software, where properties such as flow nature, maximum velocity and pressure drop were examined. A numerical model validation process was carried out with an application of PIV experiments. The digital models of the U-tube were obtained with an application of computer tomography. As a result of the tests, it has been noticed that the U-tube after operation has a much more distorted cross-sectional shape comparing to the shape of the new one. Moreover, the U-tube after operation is characterized by a 3-fold higher average surface roughness Sa value than one obtained in the new tube. The maximum flow velocities for the tube after operation are about 3.4% higher than ones reached for theoretical tube.
A. Gogolin; M. Wasilewski; G. Ligus; S. Wojciechowski; B. Gapinski; J.B. Krolczyk; D. Zajac; G.M. Krolczyk. Influence of geometry and surface morphology of the U-tube on the fluid flow in the range of various velocities. Measurement 2020, 164, 108094 .
AMA StyleA. Gogolin, M. Wasilewski, G. Ligus, S. Wojciechowski, B. Gapinski, J.B. Krolczyk, D. Zajac, G.M. Krolczyk. Influence of geometry and surface morphology of the U-tube on the fluid flow in the range of various velocities. Measurement. 2020; 164 ():108094.
Chicago/Turabian StyleA. Gogolin; M. Wasilewski; G. Ligus; S. Wojciechowski; B. Gapinski; J.B. Krolczyk; D. Zajac; G.M. Krolczyk. 2020. "Influence of geometry and surface morphology of the U-tube on the fluid flow in the range of various velocities." Measurement 164, no. : 108094.
The aim of this study was to analyse the effect of varying the vortex finder diameter and its insertion length on the flow field and overall performance in a square cyclone. A total of 15 different vortex finder configurations with 5 different diameters, each having 3 different insertion lengths, were analyzed. An in-depth analysis of flow field inside the separator was conducted by using stereoscopic particle image velocimetry (Stereo-PIV) and large eddy simulation (LES). The former makes use of two cameras that focused simultaneously over the region of interest to record the details of the flow field, whereas the latter approach directly resolves a large part of the flow and provides the three-dimensional time-dependent details of the turbulent flows. The results extracted from PIV and LES – viz. mean tangential, mean axial, and mean radial velocities – were compared, and good agreement was observed between the two. In addition, the separation efficiency and Euler number (Eu) were evaluated experimentally and by using LES. Conclusive results indicate that the geometric shapes of the vortex finder have a significant effect on the performance of square cyclone separators. Decreasing the diameter of the vortex finder resulted in a considerable increase in Eu compared to the base variant (maximal increase in Eu amounted to about 660%). However, increasing the diameter of the vortex finder decreased Eu by about 55%. An optimally configured geometry of the vortex finder increased overall separation efficiency by 16%.
Marek Wasilewski; Lakhbir Singh Brar; Grzegorz Ligus. Experimental and numerical investigation on the performance of square cyclones with different vortex finder configurations. Separation and Purification Technology 2020, 239, 116588 .
AMA StyleMarek Wasilewski, Lakhbir Singh Brar, Grzegorz Ligus. Experimental and numerical investigation on the performance of square cyclones with different vortex finder configurations. Separation and Purification Technology. 2020; 239 ():116588.
Chicago/Turabian StyleMarek Wasilewski; Lakhbir Singh Brar; Grzegorz Ligus. 2020. "Experimental and numerical investigation on the performance of square cyclones with different vortex finder configurations." Separation and Purification Technology 239, no. : 116588.
This paper reports the results of visualization research involving a heat exchanger applied for waste heat recovery using of Digital Particle Image Velocimetry (DPIV) method. Five louver dampers configurations responsible for typical operation modes were tested. As a consequence, airflow maldistribution in the tube bundle section and bypass section were identified and described. Based on the measurements and analysis carried out, the authors have developed a way to implement design changes to optimize gas distribution inside the unit.
Grzegorz Ligus; Daniel Zając; Jatinkumar Panchal. Effect on louver dampers configuration on gas maldistribution in a heat exchanger for waste heat recovery. E3S Web of Conferences 2019, 100, 00046 .
AMA StyleGrzegorz Ligus, Daniel Zając, Jatinkumar Panchal. Effect on louver dampers configuration on gas maldistribution in a heat exchanger for waste heat recovery. E3S Web of Conferences. 2019; 100 ():00046.
Chicago/Turabian StyleGrzegorz Ligus; Daniel Zając; Jatinkumar Panchal. 2019. "Effect on louver dampers configuration on gas maldistribution in a heat exchanger for waste heat recovery." E3S Web of Conferences 100, no. : 00046.
This paper presents experimental studies on the optimization of two-phase fluid flow in an airlift pump. Airlift pumps, also known as mammoth pumps, are devices applied for vertical transport of liquids with the use of gas. Their operating principle involves the existence of a density gradient. This paper reports the results of experimental studies into the hydrodynamic effects of the airlift pump. The studies involved optical imaging of two-phase gas-liquid flow in a riser pipe. The visualization was performed with high-speed visualization techniques. The studies used a transparent model of airlift pump with a rectangular cross-section of the riser. The assessment of the airlift pump operation is based on the image grey-level analysis to provide the identification of two-phase flow regimes. The scope of the study also involved the determination of void fraction and pressure drops. The tests were carried out in a channel with dimensions 35 × 20 × 2045 mm with the gas flux range 0.2–15.0 m3/h. For the assessment of the two-phase flow pattern Probability Density Function (PDF) was applied. On the basis of the obtained results, a new method for selecting the optimum operating regime of airlift pump was derived. This method provides the finding of stability and efficiency of liquid transport. It can also be applied to determine the correlation between the total lifting efficiency and the required gas flux for proper operation of the airlift pump.
Grzegorz Ligus; Daniel Zając; Maciej Masiukiewicz; Stanisław Anweiler. A New Method of Selecting the Airlift Pump Optimum Efficiency at Low Submergence Ratios with the Use of Image Analysis. Energies 2019, 12, 735 .
AMA StyleGrzegorz Ligus, Daniel Zając, Maciej Masiukiewicz, Stanisław Anweiler. A New Method of Selecting the Airlift Pump Optimum Efficiency at Low Submergence Ratios with the Use of Image Analysis. Energies. 2019; 12 (4):735.
Chicago/Turabian StyleGrzegorz Ligus; Daniel Zając; Maciej Masiukiewicz; Stanisław Anweiler. 2019. "A New Method of Selecting the Airlift Pump Optimum Efficiency at Low Submergence Ratios with the Use of Image Analysis." Energies 12, no. 4: 735.
The aim of this study was to develop a CFD model for initial qualitative analysis of the operation of the pneumatic nozzle used for dry coating. The calibration consisted in comparing the droplets velocity yielded by the model with our own experimental data. The impact of the sheet and ligament constants as well as of the application of secondary coalescence and breakup models on dispersed phase velocity were taken into consideration. It turned out that the secondary phenomena had the largest impact on the dispersed phase velocity. Only after they had been taken into consideration was the agreement between the computation results and empirical data satisfactory. Afterwards, the best set-up of the model was used for describing the plasticizer atomization in a draft tube of a spout-fluid bed apparatus. It was concluded that this process should be carried out with the atomizing gas at a pressure of 2·105 Pa.
Wojciech Ludwig; Daniel Zając; Grzegorz Ligus; Piotr Korman. Analysis of pneumatic nozzle operation with the stochastic Euler-Lagrange model. Chemical Engineering Science 2019, 197, 386 -403.
AMA StyleWojciech Ludwig, Daniel Zając, Grzegorz Ligus, Piotr Korman. Analysis of pneumatic nozzle operation with the stochastic Euler-Lagrange model. Chemical Engineering Science. 2019; 197 ():386-403.
Chicago/Turabian StyleWojciech Ludwig; Daniel Zając; Grzegorz Ligus; Piotr Korman. 2019. "Analysis of pneumatic nozzle operation with the stochastic Euler-Lagrange model." Chemical Engineering Science 197, no. : 386-403.
This paper reports the results of a study into the effect of the selection of a method of discretization of the computational domain on the solid particles separation process in a cyclone separator. The selection of an optimum discretization method to be implemented in a computational domain forms a particularly important task during analysis using CFD. The process of discretization largely affects the precision of the results gained using the CFD models as well as independence of the results on the mesh density and duration of the computations. The comparative analysis was performed on the basis of the results of experimental and numerical research with regard to the separation efficiency and pressure drop. It was observed that the computational domains generated on the basis of hexagonal meshes provide the best conformity of the results in terms of the separation efficiency, which is the key parameter applied to assess the quality of a cyclone separator.
Marek Wasilewski; Grzegorz Ligus. Effect of discretization method of a computational domain on particle separation in a cyclone separator. E3S Web of Conferences 2018, 44, 00185 .
AMA StyleMarek Wasilewski, Grzegorz Ligus. Effect of discretization method of a computational domain on particle separation in a cyclone separator. E3S Web of Conferences. 2018; 44 ():00185.
Chicago/Turabian StyleMarek Wasilewski; Grzegorz Ligus. 2018. "Effect of discretization method of a computational domain on particle separation in a cyclone separator." E3S Web of Conferences 44, no. : 00185.
This paper contains the results of experimental study concerned with liquid mixing process using a stirrer located in a rectangular vessel. The current study applied Digital Particle Image Velocimetry technique (DPIV). On the basis of non-invasive measurements, velocity vector profiles were determined with regard to the velocity of the mixing process, and they were subsequently applied for identification and assessment of liquid circulation in a vessel. The correlation between the rotational speed of the stirrer and fluctuations and directions of the liquid flow velocity were determined. This paper focuses on the assessment of the mixing intensity resulting from the rectangular geometry of the vessel. The study proposes and develops a dependence between the shape of the velocity profile of the circulating liquid and the intensity of the mixing process. The study demonstrates the existence of suitable conditions for performing mixing processes in rectangular vessels.
Grzegorz Ligus; Marek Wasilewski. Impact of stirrer rotational speed on liquid circulation in a rectangular vessel – a study applying DPIV. E3S Web of Conferences 2018, 44, 00096 .
AMA StyleGrzegorz Ligus, Marek Wasilewski. Impact of stirrer rotational speed on liquid circulation in a rectangular vessel – a study applying DPIV. E3S Web of Conferences. 2018; 44 ():00096.
Chicago/Turabian StyleGrzegorz Ligus; Marek Wasilewski. 2018. "Impact of stirrer rotational speed on liquid circulation in a rectangular vessel – a study applying DPIV." E3S Web of Conferences 44, no. : 00096.
The operation of an internal combustion engine in a transient state is related to constant changes in cylinder filling degree. Managing a steady course of engine torque demands constant corrections in the volume of air delivered to the engine. In this work, different engine throttle management strategies were analyzed. The effect of throttle velocity on emissions was depicted. The research has shown that the greatest value of work density is reached by the IC engine for relatively low values of throttle angle. For shown values, disturbances in air flow in engine intake which may adversely affect emissions due to uneven cylinder filling were researched with the use of Digital Particle Image Velocimetry. The conducted research has shown significant unevennes in air supply to individual cylinders in the engine. This effect may cause discrepancies in air excess ratio for each cylinder, and result in heightened harmful substance emission.
Szymon Kołodziej; Grzegorz Ligus. Visual study of capabilities of managing IC engine filling degree vs engine ecological indicators. E3S Web of Conferences 2017, 19, 1017 .
AMA StyleSzymon Kołodziej, Grzegorz Ligus. Visual study of capabilities of managing IC engine filling degree vs engine ecological indicators. E3S Web of Conferences. 2017; 19 ():1017.
Chicago/Turabian StyleSzymon Kołodziej; Grzegorz Ligus. 2017. "Visual study of capabilities of managing IC engine filling degree vs engine ecological indicators." E3S Web of Conferences 19, no. : 1017.
This paper presents the results of an experimental study into flow through a tube bundle applied in shell-and-tube heat exchanger with segmental baffles built on an industrial scale. The reported research applied Digital Particle Image Velocimetry (PIV) technique. The study offered the determination of the velocity vector fields, which were subsequently used for identification and measurement of irregularity of flow distribution across the tube bundle. Differences in the intensity of local flow velocities in shell side were identified by velocity profiles analysis. Furthermore correlation between the map of local velocity and its location in particular tube rows was described. As a result, the three main regions of flow velocity variation throughout cross-section of the shell side were identified.
Grzegorz Ligus; Szymon Kołodziej. Investigation of irregularity of flow distribution across the tube bundle in shell-and-tube heat exchanger with segmental baffles using PIV method. E3S Web of Conferences 2017, 19, 01005 .
AMA StyleGrzegorz Ligus, Szymon Kołodziej. Investigation of irregularity of flow distribution across the tube bundle in shell-and-tube heat exchanger with segmental baffles using PIV method. E3S Web of Conferences. 2017; 19 ():01005.
Chicago/Turabian StyleGrzegorz Ligus; Szymon Kołodziej. 2017. "Investigation of irregularity of flow distribution across the tube bundle in shell-and-tube heat exchanger with segmental baffles using PIV method." E3S Web of Conferences 19, no. : 01005.