The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Youngdo Choi - One of the best experts on this subject based on the ideXlab platform.
-
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.
-
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.
Zhenmu Chen - One of the best experts on this subject based on the ideXlab platform.
-
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.
-
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.
Y-d Choi - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Suction Pipe leaning angle and water level on the internal flow of pump sump
IOP Conference Series: Earth and Environmental Science, 2016Co-Authors: Z-m Chen, S-h Park, Y-d ChoiAbstract:The pump sump, which connects forebay and intake of pump station, supplies good flow condition for the intake of the pump. If Suction sumps are improperly shaped or sized, air entraining vortices or submerged vortices may develop. This may greatly affect pump operation if vortices grow to an appreciable extent. Moreover, the noise and vibration of the pump can be increased by the remaining of vortices in the pump flow passage. Therefore, the vortices in the pump flow passage have to be reduced for a good performance of pump sump station. In this study, the effect of Suction Pipe leaning angle on the pump sump internal flow with different water level has been investigated by CFD analysis. Moreover, an elbow type Pipe was also investigated. There are 3 leaning angles with 0°, 45° and 90° for the Suction Pipe. The Suction Pipe inlet centre is kept same for all the cases. In addition, the three different water levels of H/D=1.85, 1.54, and 1.31, is applied to different Suction Pipe types. The result shows that the amount of air sucked into the Suction Pipe increases with increasing the Suction Pipe leaning angle. Especially for the horizontal Suction Pipe, there is maximum air sucked into the Suction Pipe. However, there is certain effect of the elbow type bell mouth installation in the horizontal Suction Pipe on suppressing the amount of air sucked into the Pipe. Moreover, vertical Suction Pipe plays an effective role on reducing the free surface vortex intake area.
Abir Issa - One of the best experts on this subject based on the ideXlab platform.
-
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, Gerard Bois, Sophie Simonet, 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.
-
numerical simulation of flow field in water pump sump and inlet Suction Pipe
IOP Conference Series: Earth and Environmental Science, 2010Co-Authors: Annieclaude Bayeullaine, Gerard 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.
Shi Rui Liu - One of the best experts on this subject based on the ideXlab platform.
-
Model of the yarn twist propagation in compact spinning with a pneumatic groove
Fibres and Textiles in Eastern Europe, 2011Co-Authors: Zhuan Yong Zou, Long Di Cheng, Yu Feng Guo, Shao Ming Zheng, Shi Rui LiuAbstract:Compact spinning with a pneumatic groove utilises the transverse air\nforce and mechanical force of the pneumatic groove to condense the fibre\nbundle in order to eliminate the spinning triangle. This paper analyses\nthe twist resistance moments and torsion moment in the process of twist\npropagation. Results from this research confirm that the twist\npropagation is affected by the spinning tension, the negative pressure\nin the air Suction Pipe, the related yarn properties (the yarn diameter,\nyarn twist, and the torsion rigidity of the yarn), and the related\nstructure parameters of the pneumatic groove roller (the friction\ncoefficient between the pneumatic groove and the fibre bundle, the\nnumber of round pores, the diameter of the round pore, the distribution\nrule of round pores in the condensing zone). The twist propagation model\ndetermines the critical condition of spinning a compact yarn,\ncharacterised by the critical mean pressure (i.e. corresponding to the\ncritical negative pressure in the air Suction Pipe). The higher the yarn\ntwist, the higher the torsion rigidity of the yarn, and the lower the\nspinning tension required, the higher the critical mean pressure.
