The Experts below are selected from a list of 10005 Experts worldwide ranked by ideXlab platform
Youngdo Choi - One of the best experts on this subject based on the ideXlab platform.
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Effect of suction pipe inlet condition on the occurrence of vortex in pump Sump
IOP Conference Series: Earth and Environmental Science, 2019Co-Authors: Zhenmu Chen, Youngdo ChoiAbstract:Pump Sump is an indispensable facility in irrigation, drainage, agriculture and industrial processes. The water intake conditions play an important role on the performance of the whole system. However, there are different kinds of undesirable vortices usually occurred in pump Sump, such as submerged vortex, air entrained vortex. Accompanying with the variety of vortex, noise and vibration are also produced. In this study, a scale down model of pump Sump has been designed and constructed. The occurrence of vortex is the concentrated target which was investigated under different suction pipe inlet conditions. Moreover, with respect to the different water levels, flow rate and a fixed distance from the bottom to suction pipe bell mouth detailed experiments were conducted. In addition, a Computational Fluid Dynamics (CFD) analysis method also has been carried out in this paper, aimed at verifying the effect of pipe inlet condition on visualization and formation of vortex which have been obtained by experiment. The comparison of CFD analysis and detailed experiments results were discussed and described.
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the effect of suction pipe leaning angle on the internal flow of pump Sump
Journal of the Korean Society of Marine Engineering, 2015Co-Authors: Zhenmu Chen, Youngdo ChoiAbstract:A better flow condition for the intake of pump is provided by the Sump pump that connects the forebay to the intake of the pump station. If the suction Sump is improperly shaped or sized, air-entraining vortices or submerged vortices may develop. These phenomena may greatly affect pump operation if vortices become sufficiently large. Moreover, any remaining vortices in the pump flow passage may result in an increase in the noise and vibration of the pump. Therefore, the vortices in the pump flow passage must be reduced to achieve good pump Sump station performance. In this study, the effect of suction pipe leaning angle on the pump Sump’s internal flow is investigated. Additionally, a pipe type with an elbow shape is investigated. The results show that the air entraining vortices occur under the condition of a water level ratio H/D = 1.31 for each suction pipe type.
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a study on the effectiveness of an anti vortex device in the Sump model by experiment and cfd
IOP Conference Series: Earth and Environmental Science, 2012Co-Authors: Youngdo Choi, J W ChoiAbstract:The head-capacity curves of pumps developed by the pump manufacturer are based on tests of a single pump operation in a semi-infinite basin with no closed walls of floors and with no stray currents. Therefore, the flow into the pump intake has no vortices of swirling. However, pump station designers relying on these curves to define the operating conditions for the selected pump sometimes experience reductions in capacity and efficiency, as well as an increase of vibration and additional noise. Therefore, Sump model testing is necessary in order to examine the flow structure around intake. In this study, flow uniformity according to the flow distribution in the pump intake channel is examined to find out the cause of vortex occurrence in detail by experiment and CFD. Furthermore, the effectiveness of an anti vortex device for the suppression of the vortex occurrence in a single intake pump Sump model has been examined by AVD type. The AVDs used for experimental testing, one of which has the shape of a rectangular bar and the other was a trident shape, are attached at the bottom of pump intake channel just below the bell-mouth. The AVD type for CFD test is in the shape of a trident. The experimental Sump model was scaled down by a ratio of 1:8 whereas the CFD Sump model was scaled to the actual size.
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flow uniformity in a multi intake pump Sump model
Journal of Mechanical Science and Technology, 2010Co-Authors: Jongwoong Choi, Youngdo Choi, Changgoo Kim, Youngho LeeAbstract:The head-capacity curves for pumps developed by the pump manufacturer are based on tests of a single pump operation in a semi-infinite basin with no close walls or floors and with no stray currents. Therefore, flow into the pump intake is with no vortices or swirling. However, pump station designers relying on these curves to define the operating conditions for the pump selected sometimes experience reductions of capacity and efficiency, as well as the increase of vibration and additional noise, which are caused by free air mixed with the pump inlet flow. Therefore, Sump model test is necessary in order to examine the flow structure around pump intake. In this study, flow uniformity according to the flow distribution in the pump intake channel is examined to find out the cause of vortex occurrence in detail. A multi-intake pump Sump model with 7 pump intakes and a single-intake pump Sump model are adopted for the investigation. Furthermore, effectiveness of anti-submerged vortex device (AVD) for the suppression of the vortex occurrence in a single pump intake, as well as in a multi-intake pump Sump model has been examined by the methods of experiment and numerical analysis. The results show that most high value of flow uniformity is found at the inlet of pump intakes #3 and 5 in the multi-intake pump Sump with 7 pump intakes. Therefore, when the pump station is designed, the flow patterns at the upstream region of pump intake inlet in the forebay diffusing area should be to consider in detail because the unbalanced flow at the channel inlet region gives considerable influence on the vortex occurrence around bell-mouth. Strong submerged vortex can be successfully suppressed by AVD installation on the bottom of pump intake channel just below the bell mouth.
Deyou Li - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of hysteresis characteristic in the hump region of a pump turbine model
Renewable Energy, 2018Co-Authors: Deyou Li, Hongjie WangAbstract:Abstract Pumped-storage technology is one of the cleanest methods of energy conversion. The stable and safe operation of pump-turbines as key parts of pumped-storage power plants are becoming more and more important with the rapid increase in the capacities, specific speeds and heads of pump-turbines. The hump characteristic is one of the unique unstable features that significantly influences the stability of pump-turbines. Recently, an interesting phenomenon hysteresis characteristic was found in the hump region, which enlarges the unstable region and results in a more unstable characteristic of the pump-turbine. In the present study, based on experimental validation, steady simulations were performed to predict the hump characteristic as well as the hysteresis phenomenon. An analysis of the hydraulic loss and flow field shows that the hump characteristic and the hysteresis phenomenon are caused by the decrease in the work of the runner and the increase in hydraulic loss, which are induced from vortices in the guide/stay vanes and backflow near the shroud at the runner inlet. For the same operating condition, owing to the difference in the input direction, the states of vortices and backflow are different, resulting in the hysteresis characteristic.
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hysteresis characteristic in the hump region of a pump turbine model
Energies, 2016Co-Authors: Deyou Li, Hongjie Wang, Jinxia Chen, Torbjorn K NielsenAbstract:The hump feature is one of the major instabilities in pump-turbines. When pump-turbines operate in the hump region, strong noise and serious fluctuations can be observed, which are harmful to their safe and stable operation and can even destroy the whole unit as well as water conveyance system. In this paper, a low specific speed ( n q = 36.1 min −1 ) pump-turbine model was experimentally investigated. Firstly, the hump characteristic was obtained under 19 mm guide vane opening conditions. More interestingly, when the hump characteristic was measured in two directions (increasing and decreasing the discharge), characteristic hysteresis was found in the hump region. The analysis of performance characteristics reveals that the hump instability is the result of Euler momentum and hydraulic losses, and different Euler momentum and hydraulic losses in the two development processes lead to the hysteresis phenomenon. Then, 12 pressure sensors were mounted in the different parts of the pump-turbine model to obtain the time and frequency characteristics. The analysis of the corresponding fast Fourier transform confirms that the hump characteristic is related to low-frequency (0.04–0.15 times rotational frequency) vortices. The occurrence and cessation of vortices depend on the operating condition and measurement direction, which contribute to the hysteresis feature. Finally, the type of the low-frequency vortices was analyzed through the cross power spectrum.
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entropy production analysis for hump characteristics of a pump turbine model
Chinese Journal of Mechanical Engineering, 2016Co-Authors: Deyou Li, Hongjie Wang, Ruzhi Gong, Gaoming XiangAbstract:The hump characteristic is one of the main problems for the stable operation of pump turbines in pump mode. However, traditional methods cannot reflect directly the energy dissipation in the hump region. In this paper, 3D simulations are carried out using the SST k-ω turbulence model in pump mode under different guide vane openings. The numerical results agree with the experimental data. The entropy production theory is introduced to determine the flow losses in the whole passage, based on the numerical simulation. The variation of entropy production under different guide vane openings is presented. The results show that entropy production appears to be a wave, with peaks under different guide vane openings, which correspond to wave troughs in the external characteristic curves. Entropy production mainly happens in the runner, guide vanes and stay vanes for a pump turbine in pump mode. Finally, entropy production rate distribution in the runner, guide vanes and stay vanes is analyzed for four points under the 18 mm guide vane opening in the hump region. The analysis indicates that the losses of the runner and guide vanes lead to hump characteristics. In addition, the losses mainly occur in the runner inlet near the band and on the suction surface of the blades. In the guide vanes and stay vanes, the losses come from pressure surface of the guide vanes and the wake effects of the vanes. A new insight-entropy production analysis is carried out in this paper in order to find the causes of hump characteristics in a pump turbine, and it could provide some basic theoretical guidance for the loss analysis of hydraulic machinery.
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Frequency spectrum analysis for hump characteristic in a pump turbine
2014 ISFMFE - 6th International Symposium on Fluid Machinery and Fluid Engineering, 2014Co-Authors: Deyou Li, Hongjie Wang, Gaoming Xiang, Ruzhi GongAbstract:In order to analyze the instabilities during the hump region, three dimensional unsteady incompressible simulations are carried out using SST k-ω turbulence model for a scaled model pump turbine at the 18 mm guide vanes opening in pump mode. And 12 monitoring points are set on the whole pump turbine model passage. Then, pressure fluctuation for different operation conditions is analyzed compared with the best efficiency point. Finally this research states the cause of dominant frequency and the principle of spectrum varying with discharge. The results show that blade passing frequency occurs mainly at the best efficiency point, and for all the monitoring points excluding guide vane inlet point, the value of 0.25-1 time rotation frequency feathers obviously higher than the blade passing frequency one with discharge declining, especially in the hump region.
Hongjie Wang - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of hysteresis characteristic in the hump region of a pump turbine model
Renewable Energy, 2018Co-Authors: Deyou Li, Hongjie WangAbstract:Abstract Pumped-storage technology is one of the cleanest methods of energy conversion. The stable and safe operation of pump-turbines as key parts of pumped-storage power plants are becoming more and more important with the rapid increase in the capacities, specific speeds and heads of pump-turbines. The hump characteristic is one of the unique unstable features that significantly influences the stability of pump-turbines. Recently, an interesting phenomenon hysteresis characteristic was found in the hump region, which enlarges the unstable region and results in a more unstable characteristic of the pump-turbine. In the present study, based on experimental validation, steady simulations were performed to predict the hump characteristic as well as the hysteresis phenomenon. An analysis of the hydraulic loss and flow field shows that the hump characteristic and the hysteresis phenomenon are caused by the decrease in the work of the runner and the increase in hydraulic loss, which are induced from vortices in the guide/stay vanes and backflow near the shroud at the runner inlet. For the same operating condition, owing to the difference in the input direction, the states of vortices and backflow are different, resulting in the hysteresis characteristic.
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hysteresis characteristic in the hump region of a pump turbine model
Energies, 2016Co-Authors: Deyou Li, Hongjie Wang, Jinxia Chen, Torbjorn K NielsenAbstract:The hump feature is one of the major instabilities in pump-turbines. When pump-turbines operate in the hump region, strong noise and serious fluctuations can be observed, which are harmful to their safe and stable operation and can even destroy the whole unit as well as water conveyance system. In this paper, a low specific speed ( n q = 36.1 min −1 ) pump-turbine model was experimentally investigated. Firstly, the hump characteristic was obtained under 19 mm guide vane opening conditions. More interestingly, when the hump characteristic was measured in two directions (increasing and decreasing the discharge), characteristic hysteresis was found in the hump region. The analysis of performance characteristics reveals that the hump instability is the result of Euler momentum and hydraulic losses, and different Euler momentum and hydraulic losses in the two development processes lead to the hysteresis phenomenon. Then, 12 pressure sensors were mounted in the different parts of the pump-turbine model to obtain the time and frequency characteristics. The analysis of the corresponding fast Fourier transform confirms that the hump characteristic is related to low-frequency (0.04–0.15 times rotational frequency) vortices. The occurrence and cessation of vortices depend on the operating condition and measurement direction, which contribute to the hysteresis feature. Finally, the type of the low-frequency vortices was analyzed through the cross power spectrum.
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entropy production analysis for hump characteristics of a pump turbine model
Chinese Journal of Mechanical Engineering, 2016Co-Authors: Deyou Li, Hongjie Wang, Ruzhi Gong, Gaoming XiangAbstract:The hump characteristic is one of the main problems for the stable operation of pump turbines in pump mode. However, traditional methods cannot reflect directly the energy dissipation in the hump region. In this paper, 3D simulations are carried out using the SST k-ω turbulence model in pump mode under different guide vane openings. The numerical results agree with the experimental data. The entropy production theory is introduced to determine the flow losses in the whole passage, based on the numerical simulation. The variation of entropy production under different guide vane openings is presented. The results show that entropy production appears to be a wave, with peaks under different guide vane openings, which correspond to wave troughs in the external characteristic curves. Entropy production mainly happens in the runner, guide vanes and stay vanes for a pump turbine in pump mode. Finally, entropy production rate distribution in the runner, guide vanes and stay vanes is analyzed for four points under the 18 mm guide vane opening in the hump region. The analysis indicates that the losses of the runner and guide vanes lead to hump characteristics. In addition, the losses mainly occur in the runner inlet near the band and on the suction surface of the blades. In the guide vanes and stay vanes, the losses come from pressure surface of the guide vanes and the wake effects of the vanes. A new insight-entropy production analysis is carried out in this paper in order to find the causes of hump characteristics in a pump turbine, and it could provide some basic theoretical guidance for the loss analysis of hydraulic machinery.
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Frequency spectrum analysis for hump characteristic in a pump turbine
2014 ISFMFE - 6th International Symposium on Fluid Machinery and Fluid Engineering, 2014Co-Authors: Deyou Li, Hongjie Wang, Gaoming Xiang, Ruzhi GongAbstract:In order to analyze the instabilities during the hump region, three dimensional unsteady incompressible simulations are carried out using SST k-ω turbulence model for a scaled model pump turbine at the 18 mm guide vanes opening in pump mode. And 12 monitoring points are set on the whole pump turbine model passage. Then, pressure fluctuation for different operation conditions is analyzed compared with the best efficiency point. Finally this research states the cause of dominant frequency and the principle of spectrum varying with discharge. The results show that blade passing frequency occurs mainly at the best efficiency point, and for all the monitoring points excluding guide vane inlet point, the value of 0.25-1 time rotation frequency feathers obviously higher than the blade passing frequency one with discharge declining, especially in the hump region.
Abir Issa - One of the best experts on this subject based on the ideXlab platform.
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The importance of the knowledge of flow stream in water Sump pump
2013Co-Authors: Annie-claude Bayeul-laine, Abir Issa, Sophie Simonet, Gérard BoisAbstract:Numerous different experimental and numerical methods have been developed and are already improved in order to get rather good flow descriptions inside pump components. These calculations are generally realized assuming uniform and steady flow conditions, in particular for the inlet conditions. However, few studies are devoted to non-uniform upstream conditions, especially in case of water pump Sump before entering the pump inlet tube. Free air-core vortex occurring at the water-intake pipe is an important problem encountered in hydraulic engineering because they reduce pump performances and may have large effects on the operating conditions. The paper deals with flow pattern inside Sump pump. Experiments were conducted in order to select best positions of the suction pipe of water-intake specific configurations. The numerical studies try to reproduce the flow pattern of these experiments and confirm the influence of geometrical parameters on the flow structure in such a Sump. These numerical studies points out the need of unsteady calculation in order to get a better understanding of flow behaviour including two-phases flow models.
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Two-phase numerical study of the flow field formed in water pump Sump: influence of air entrainment
IOP Conference Series: Earth and Environmental Science, 2012Co-Authors: Annie-claude Bayeul-laine, Sophie Simonet, Gérard Bois, Abir IssaAbstract:In a pump Sump it is imperative that the amount of non-homogenous flow and entrained air be kept to a minimum. Free air-core vortex occurring at a water-intake pipe is an important problem encountered in hydraulic engineering. These vortices reduce pump performances, may have large effects on the operating conditions and lead to increase plant operating costs.This work is an extended study starting from 2006 in LML and published by ISSA and al. in 2008, 2009 and 2010. Several cases of Sump configuration have been numerically investigated using two specific commercial codes and based on the initial geometry proposed by Constantinescu and Patel. Fluent and Star CCM+ codes are used in the previous studies. The results, obtained with a structured mesh, were strongly dependant on main geometrical Sump configuration such as the suction pipe position, the submergence of the suction pipe on one hand and the turbulence model on the other hand. Part of the results showed a good agreement with experimental investigations already published. Experiments, conducted in order to select best positions of the suction pipe of a water-intake Sump, gave qualitative results concerning flow disturbances in the pump-intake related to Sump geometries and position of the pump intake. The purpose of this paper is to reproduce the flow pattern of experiments and to confirm the geometrical parameter that influences the flow structure in such a pump. The numerical model solves the Reynolds averaged Navier-Stokes (RANS) equations and VOF multiphase model. STAR CCM+ with an adapted mesh configuration using hexahedral mesh with prism layer near walls was used. Attempts have been made to calculate two phase unsteady flow for stronger mass flow rates and stronger submergence with low water level in order to be able to capture air entrainment. The results allow the knowledge of some limits of numerical models, of mass flow rates and of submergences for air entrainment. In the validation of this numerical model, emphasis was placed on the prediction of the number, location, size and strength of the various types of vortices coming from the free surface. Contours of vorticity at free surface, air cores, isoline of pressure surface were particularly examined for some cases. Streamlines issued from the free surface and the volume of fraction of air allows visualizing the air entrainment.
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numerical simulation of flow field in water pump Sump and inlet suction pipe
IOP Conference Series: Earth and Environmental Science, 2010Co-Authors: Annieclaude Bayeullaine, Gérard Bois, Abir IssaAbstract:There are several important considerations in the design of a suction supply Sump. It is imperative that the amount of turbulence and entrained air be kept to a minimum. Free air-core vortex occurring at a water-intake pipe is an important problem encountered in hydraulic engineering. These vortices may reduce pump performances, have large effects on the operating conditions and lead to increase plant operating costs. Experiments, conducted in order to select best positions of the suction pipe of a water-intake Sump, show qualitative results concerning flow disturbances in the pump-intake related to Sump geometries and position of the pump intake. The purpose of the paper is to reproduce the flow pattern and confirm the geometrical parameter influences of the flow behavior in such a pump. The numerical model used solves the Reynolds averaged Navier-Stokes (RANS) equations and VOF multiphase model for two cases. In the validation of this numerical model, emphasis was placed on the prediction of the number, location, size and strength of the various types of vortices. Previous studies, without simulation of air entrainment, have shown the influence on a single type of mesh with different cell numbers, different intake pipe depths and different water levels, for two turbulence models closure.
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numerical simulation of flow field in water pump Sump and inlet suction pipe
IOP Conference Series: Earth and Environmental Science, 2010Co-Authors: Annieclaude Bayeullaine, Gérard Bois, Abir IssaAbstract:There are several important considerations in the design of a suction supply Sump. It is imperative that the amount of turbulence and entrained air be kept to a minimum. Free air-core vortex occurring at a water-intake pipe is an important problem encountered in hydraulic engineering. These vortices may reduce pump performances, have large effects on the operating conditions and lead to increase plant operating costs. Experiments, conducted in order to select best positions of the suction pipe of a water-intake Sump, show qualitative results concerning flow disturbances in the pump-intake related to Sump geometries and position of the pump intake. The purpose of the paper is to reproduce the flow pattern and confirm the geometrical parameter influences of the flow behavior in such a pump. The numerical model used solves the Reynolds averaged Navier-Stokes (RANS) equations and VOF multiphase model for two cases. In the validation of this numerical model, emphasis was placed on the prediction of the number, location, size and strength of the various types of vortices. Previous studies, without simulation of air entrainment, have shown the influence on a single type of mesh with different cell numbers, different intake pipe depths and different water levels, for two turbulence models closure.
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Numerical study of the influence of Geometrical Parameters on flow in water Pump-Sump
2009Co-Authors: Abir Issa, Annie-claude Bayeul-laine, Gérard BoisAbstract:Water for irrigation, domestic and industrial supply as well for some power generation is normally drawn directly from rivers or from reservoir through Sumps. The flow at the pump section Sump may have large effects on the pump performances and the operating conditions. The flow patterns in the Sump are mainly determined by the shape and scale of the Sump. However, it's not always possible to design a Sump pump to provide uniform and stable flow to pumps, due to site constraints. For example in some cases air entraining (surface and subsurface vortex) occurs. These vortices may reduce pump performances and lead to increase plant operating costs. It becomes essential to investigate the pump Sump to avoid these non uniformities inlet flow problems. Two approaches (experimental and numerical) are generally followed for such investigation. The numerical approach usually used solves the Reynolds averaged Navier-Stokes (RANS) equations with a near-wall turbulence model. In the validation of this numerical model, emphasis was placed on the prediction of the number, the location, the size and the strength of the various types of vortices. A previous study done by the same hauteur of this one [1], has shown the influence on a single type of mesh with different cell numbers, different intake pipe depths and different water levels, for two turbulence models closure. The present paper mainly focuses, first, on the effect of pump intake location in the Sump and secondly on the effect of several inlet velocity gradients at inlet Sump section.
Gérard Bois - One of the best experts on this subject based on the ideXlab platform.
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The importance of the knowledge of flow stream in water Sump pump
2013Co-Authors: Annie-claude Bayeul-laine, Abir Issa, Sophie Simonet, Gérard BoisAbstract:Numerous different experimental and numerical methods have been developed and are already improved in order to get rather good flow descriptions inside pump components. These calculations are generally realized assuming uniform and steady flow conditions, in particular for the inlet conditions. However, few studies are devoted to non-uniform upstream conditions, especially in case of water pump Sump before entering the pump inlet tube. Free air-core vortex occurring at the water-intake pipe is an important problem encountered in hydraulic engineering because they reduce pump performances and may have large effects on the operating conditions. The paper deals with flow pattern inside Sump pump. Experiments were conducted in order to select best positions of the suction pipe of water-intake specific configurations. The numerical studies try to reproduce the flow pattern of these experiments and confirm the influence of geometrical parameters on the flow structure in such a Sump. These numerical studies points out the need of unsteady calculation in order to get a better understanding of flow behaviour including two-phases flow models.
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Two-phase numerical study of the flow field formed in water pump Sump: influence of air entrainment
IOP Conference Series: Earth and Environmental Science, 2012Co-Authors: Annie-claude Bayeul-laine, Sophie Simonet, Gérard Bois, Abir IssaAbstract:In a pump Sump it is imperative that the amount of non-homogenous flow and entrained air be kept to a minimum. Free air-core vortex occurring at a water-intake pipe is an important problem encountered in hydraulic engineering. These vortices reduce pump performances, may have large effects on the operating conditions and lead to increase plant operating costs.This work is an extended study starting from 2006 in LML and published by ISSA and al. in 2008, 2009 and 2010. Several cases of Sump configuration have been numerically investigated using two specific commercial codes and based on the initial geometry proposed by Constantinescu and Patel. Fluent and Star CCM+ codes are used in the previous studies. The results, obtained with a structured mesh, were strongly dependant on main geometrical Sump configuration such as the suction pipe position, the submergence of the suction pipe on one hand and the turbulence model on the other hand. Part of the results showed a good agreement with experimental investigations already published. Experiments, conducted in order to select best positions of the suction pipe of a water-intake Sump, gave qualitative results concerning flow disturbances in the pump-intake related to Sump geometries and position of the pump intake. The purpose of this paper is to reproduce the flow pattern of experiments and to confirm the geometrical parameter that influences the flow structure in such a pump. The numerical model solves the Reynolds averaged Navier-Stokes (RANS) equations and VOF multiphase model. STAR CCM+ with an adapted mesh configuration using hexahedral mesh with prism layer near walls was used. Attempts have been made to calculate two phase unsteady flow for stronger mass flow rates and stronger submergence with low water level in order to be able to capture air entrainment. The results allow the knowledge of some limits of numerical models, of mass flow rates and of submergences for air entrainment. In the validation of this numerical model, emphasis was placed on the prediction of the number, location, size and strength of the various types of vortices coming from the free surface. Contours of vorticity at free surface, air cores, isoline of pressure surface were particularly examined for some cases. Streamlines issued from the free surface and the volume of fraction of air allows visualizing the air entrainment.
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numerical simulation of flow field in water pump Sump and inlet suction pipe
IOP Conference Series: Earth and Environmental Science, 2010Co-Authors: Annieclaude Bayeullaine, Gérard Bois, Abir IssaAbstract:There are several important considerations in the design of a suction supply Sump. It is imperative that the amount of turbulence and entrained air be kept to a minimum. Free air-core vortex occurring at a water-intake pipe is an important problem encountered in hydraulic engineering. These vortices may reduce pump performances, have large effects on the operating conditions and lead to increase plant operating costs. Experiments, conducted in order to select best positions of the suction pipe of a water-intake Sump, show qualitative results concerning flow disturbances in the pump-intake related to Sump geometries and position of the pump intake. The purpose of the paper is to reproduce the flow pattern and confirm the geometrical parameter influences of the flow behavior in such a pump. The numerical model used solves the Reynolds averaged Navier-Stokes (RANS) equations and VOF multiphase model for two cases. In the validation of this numerical model, emphasis was placed on the prediction of the number, location, size and strength of the various types of vortices. Previous studies, without simulation of air entrainment, have shown the influence on a single type of mesh with different cell numbers, different intake pipe depths and different water levels, for two turbulence models closure.
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numerical simulation of flow field in water pump Sump and inlet suction pipe
IOP Conference Series: Earth and Environmental Science, 2010Co-Authors: Annieclaude Bayeullaine, Gérard Bois, Abir IssaAbstract:There are several important considerations in the design of a suction supply Sump. It is imperative that the amount of turbulence and entrained air be kept to a minimum. Free air-core vortex occurring at a water-intake pipe is an important problem encountered in hydraulic engineering. These vortices may reduce pump performances, have large effects on the operating conditions and lead to increase plant operating costs. Experiments, conducted in order to select best positions of the suction pipe of a water-intake Sump, show qualitative results concerning flow disturbances in the pump-intake related to Sump geometries and position of the pump intake. The purpose of the paper is to reproduce the flow pattern and confirm the geometrical parameter influences of the flow behavior in such a pump. The numerical model used solves the Reynolds averaged Navier-Stokes (RANS) equations and VOF multiphase model for two cases. In the validation of this numerical model, emphasis was placed on the prediction of the number, location, size and strength of the various types of vortices. Previous studies, without simulation of air entrainment, have shown the influence on a single type of mesh with different cell numbers, different intake pipe depths and different water levels, for two turbulence models closure.
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Numerical study of the influence of Geometrical Parameters on flow in water Pump-Sump
2009Co-Authors: Abir Issa, Annie-claude Bayeul-laine, Gérard BoisAbstract:Water for irrigation, domestic and industrial supply as well for some power generation is normally drawn directly from rivers or from reservoir through Sumps. The flow at the pump section Sump may have large effects on the pump performances and the operating conditions. The flow patterns in the Sump are mainly determined by the shape and scale of the Sump. However, it's not always possible to design a Sump pump to provide uniform and stable flow to pumps, due to site constraints. For example in some cases air entraining (surface and subsurface vortex) occurs. These vortices may reduce pump performances and lead to increase plant operating costs. It becomes essential to investigate the pump Sump to avoid these non uniformities inlet flow problems. Two approaches (experimental and numerical) are generally followed for such investigation. The numerical approach usually used solves the Reynolds averaged Navier-Stokes (RANS) equations with a near-wall turbulence model. In the validation of this numerical model, emphasis was placed on the prediction of the number, the location, the size and the strength of the various types of vortices. A previous study done by the same hauteur of this one [1], has shown the influence on a single type of mesh with different cell numbers, different intake pipe depths and different water levels, for two turbulence models closure. The present paper mainly focuses, first, on the effect of pump intake location in the Sump and secondly on the effect of several inlet velocity gradients at inlet Sump section.
