Energy Characteristics of Full Tubular Pump Device with Different Backflow Clearances Based on Entropy Production

Meng, Fan; Li, Yanjun; Pei, Ji

doi:10.3390/app11083376

Cited by 13 publications

(7 citation statements)

References 29 publications

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“…The effect of tip clearance on tip leakage flow was also studied. In addition, the increase in the clearance radius led to a disorderly flow in the impeller [15]. The total dissipation rate on the impeller suction side and near the impeller inlet increased with the backflow clearance radius, but that on the impeller [16] suction side decreased with the increase of the backflow clearance radius.…”

Section: Computational Modelmentioning

confidence: 98%

Angle-Regulating Rule of Guide Vanes of Variable Geometry Turbine Adjusting Mechanism

et al. 2023

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In recent years, more and more attention has been paid to research on variable geometry turbine engines with the increasing requirement of engine performance. Variable geometry turbine technology can significantly improve the operating performance of aero engines. Adjusting the working angle of the turbine guide vane can change the thermodynamic cycle of the engine operation, so that the turbine can respond to different engine operating conditions. Variable geometry turbines work in harsh environments. Therefore, the design of the variable geometry turbine needs to consider the effect of thermal deformations of the mechanism on operational stability. There are few research studies on variable geometry turbine adjusting mechanisms. This paper established the numerical calculation models of two adjusting mechanisms by integrating fluid mechanics, heat transfer, and dynamic theories, which are paddle and push–pull rod mechanisms. The models were applied to study the effects of components’ thermal deformations and flexible bodies on the motion characteristics of the adjusting mechanism. Furthermore, the performance of the two adjusting mechanisms was compared. The calculation results show that the paddle rod adjusting mechanism can accurately adjust the angles of guide vanes. The paddle rod adjusting mechanism has a larger driving stroke and smaller driving force than the push–pull rod adjusting mechanism. The paddle adjustment mechanism was better suited to the operational requirements of the variable geometry turbine. The research results of this paper are relevant to the design of variable geometry turbine regulation structures.

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Section: Computational Modelmentioning

confidence: 98%

Angle-Regulating Rule of Guide Vanes of Variable Geometry Turbine Adjusting Mechanism

et al. 2023

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“…In this paper, the Tabakoff and Grant erosion model is adopted to predict the internal wear of water turbine, which is widely used in the simulation of the erosion in the Francis Turbine [21][22][23]. The model is calculated based on the angle and velocity at which particles collide with the impeller (that is particle trajectories) [24,25].…”

Section: Erosion Modelmentioning

confidence: 99%

Study on the Effect of the Guide Vane Opening on the Band Clearance Sediment Erosion in a Francis Turbine

Song

Zhou²,

Song³

et al. 2022

JMSE

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Sediment erosion is a negative phenomenon for the water turbine. The purpose of this paper is to study the effect of the guide vane opening on the particle motion and sediment erosion in the band chamber using the Euler–Lagrangian approach. The software Ansys CFX and Tabakoff erosion model are used to simulate the sediment laden flow in the full flow passage of the hydraulic turbine. The results are in good agreement with the actual erosion character on site. Results show that the guide vane opening has a positive correlation with the flow in the non-clearance channel. The increase of the guide vane opening will increase the erosion of the runner blade head, but the friction wear on the outlet side of the blade surface will decrease. The rotating action of the runner makes the sediment particles in the band chamber rotate rapidly around the center of the runner and constantly collide with the band chamber wall. Under the small opening, the smaller the opening, the easier the leakage of the band clearance occurs. The unsteady flow in the band chamber will disturb the motion trajectory of particles, change the impact angle of particles, and affect the wear in the band chamber. Under different openings, the change law of the erosion in the band clearance is closely related to the change law of clearance leakage.

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“…Domestic and foreign scholars conducted detailed studies on the energy dissipation of internal flow of fluid machinery such as centrifugal pumps [ 21 , 22 ], turbines [ 23 , 24 ] and axial flow pumps [ 25 , 26 ], but there are few studies on the energy loss characteristics of the total flow pipeline of the vertical axial flow pump device using the entropy production method. In this paper, the commercial software ANSYS CFX was used to conduct a three-dimensional (3D) numerical simulation of the pump device.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Energy Loss Characteristics of Vertical Axial Flow Pump Based on Entropy Production Method under Partial Conditions

Yang

Chang

Cai³

et al. 2022

Entropy

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The energy loss of the vertical axial flow pump device increases due to the unstable internal flow, which reduces the efficiency of the pump device and increases its energy consumption of the pump device. The research results of the flow loss characteristics of the total internal conduit are still unclear. Therefore, to show the internal energy loss mechanism of the axial flow pump, this paper used the entropy production method to calculate the energy loss of the total conduit of the pump device to clarify the internal energy loss mechanism of the pump device. The results show that the energy loss of the impeller is the largest under various flow conditions, accounting for more than 40% of the total energy loss of the pump device. The variation trend of the volume average entropy production and the energy loss is similar under various flow coefficients (KQ). The volume average entropy production rate (EPR) and the energy loss decrease first and then increase with the increase of flow, the minimum volume average entropy production is 378,000 W/m3 at KQ = 0.52, and the area average EPR of the impeller increases gradually with the increase of flow. Under various flow coefficient KQ, the energy loss of campaniform inlet conduit is the smallest, accounting for less than 1% of the total energy loss. Its maximum value is 63.58 W. The energy loss of the guide vane and elbow increases with the increase of flow coefficient KQ, and the maximum ratio of energy loss to the total energy loss of the pump device is 29% and 21%, respectively, at small flow condition KQ = 0.38. The energy loss of straight outlet conduit reduces first and then increases with the increase of flow coefficient KQ. When flow coefficient KQ = 0.62, it accounts for 27% of the total energy loss of the pump device, but its area average entropy production rate (EPR) and volume average entropy production rate (EPR) are small. The main entropy production loss in the pump device is dominated by entropy production by turbulent dissipation (EPTD), and the proportion of entropy production by direct dissipation (EPDD) is the smallest.

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Energy Characteristics of Full Tubular Pump Device with Different Backflow Clearances Based on Entropy Production

Cited by 13 publications

References 29 publications

Angle-Regulating Rule of Guide Vanes of Variable Geometry Turbine Adjusting Mechanism

Angle-Regulating Rule of Guide Vanes of Variable Geometry Turbine Adjusting Mechanism

Study on the Effect of the Guide Vane Opening on the Band Clearance Sediment Erosion in a Francis Turbine

Analysis of Energy Loss Characteristics of Vertical Axial Flow Pump Based on Entropy Production Method under Partial Conditions

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