Numerical Study on Transient Dynamics in a Centrifugal Pump Considering Clearance Flow

This paper investigates the transient flow characteristics and the forces on the impeller in a single-stage centrifugal pump considering the clearance flow. The finite volume method is employed to simulate the dynamics process. First, Numerical simulation is carried out in a commercial code CFX. The external performance characteristics, internal flow structure and pressure fluctuation in the two different models, with clearance and without clearance, are compared. It is found that the existence of the clearance flow can generate more vortex and hydraulic loss, which makes the flow state more complicated. Besides, the transient radial and axial forces on the impeller are analyzed. And an optimized model with modified chamber flow field is proposed, which can provide a theoretical foundation on the structure design of the centrifugal pump.

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Numerical Study on the Influence of Inlet Guide Vanes on the Internal Flow Characteristics of Centrifugal Pump

Processes ◽

10.3390/pr8010122 ◽

2020 ◽

Vol 8 (1) ◽

pp. 122 ◽

Cited By ~ 3

Author(s):

Peifeng Lin ◽

Yongzheng Li ◽

Wenbin Xu ◽

Hui Chen ◽

Zuchao Zhu

Keyword(s):

Centrifugal Pump ◽

Numerical Study ◽

Flow Characteristics ◽

Internal Flow ◽

Low Flow ◽

Hydraulic Loss ◽

Inlet Pipe ◽

Monitoring Point ◽

Guide Vanes ◽

Sst Turbulence Model

In order to make the centrifugal pump run efficiently and stably under various working conditions, the influences of the incoming vortex flow in the inlet pipe on the main flow in the impeller is studied numerically, based on the k − ω SST turbulence model. Some guide vanes with different offset angle were added to change the statistical characteristic of the internal flow in the inlet pipe of the centrifugal pump. Both contour distributions of internal flow and statistical results of external performance are obtained and analyzed. The results show that the existence of vanes can divide the large vortex because of the reversed flow from the rotating impeller at low flow rate conditions into small vortices, which are easier to dissipate, make the velocity and pressure distribution more uniform, improve the stability of the flow in the impeller, reduce the hydraulic loss, and improve the hydraulic performance of the pump. The pump with vanes of offset angle 25° has a small pressure pulsation amplitude at each monitoring point. Comparing with the performance of the original pump, the head increased by around 2% and efficiency increased by around 2.5% of the pump with vanes of offset angle 25°.

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Numerical Simulation of Transient Flow Inside Nozzle on Gasoline Direct Injection Engine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.466-467.1237 ◽

2012 ◽

Vol 466-467 ◽

pp. 1237-1241

Author(s):

Yan Hua Wang ◽

Shi Chun Yang ◽

Yun Qing Li

Keyword(s):

Kinetic Energy ◽

Transient Flow ◽

Direct Injection ◽

Flow Characteristics ◽

Internal Flow ◽

Turbulence Kinetic Energy ◽

Gasoline Direct Injection ◽

Injection Hole ◽

Gasoline Direct Injection Engine ◽

Nozzle Configuration

To achieve transient flow characteristics at exit of nozzle orifice on gasoline direct injection engine, two phase Euler-Euler schemes was used to simulate the internal flow of the swirl nozzle. Different flow characteristics were calculated in the simulation. Different kinds of nozzle configuration were studied. Cavitaion and swirl flow occured in the nozzles. Injection hole configuration matters more than area variation of swirl tangential slot to discharge coefficient of the studied nozzle. Discharge coefficient changes a little along the injection hole length. The area of the swirl tangrntial slot plays an important throttling action in nozzle internal flow. Smaller area of swirl tangential slot generates larger degree cavitation but smaller mean injection velocity. Turbulence kinetic energy changes with the time of cavitation and swirl field occurring and the nozzle configuration. Before the appearance of cavitation, smaller inclination angle of orifice can generate more turbulence kinetic energy. After that moment, turbulence kinetic energy varies with different configuration. Along injection hole length, turbulence kinetic energy obviously varies. These flow characteristics affect primary atomization and will be as input for next spray simulation. They are also applied to design reference for injection nozzle.

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Study on Internal Flow and External Performance of a Semi-open Impeller Centrifugal Pump with Different Tip Clearances

International Journal of Turbo and Jet Engines ◽

10.1515/tjj-2014-0010 ◽

2015 ◽

Vol 32 (1) ◽

pp. 1-12 ◽

Cited By ~ 9

Author(s):

Xiao-Qi Jia ◽

Bao-Ling Cui ◽

Yu-Liang Zhang ◽

Zu-Chao Zhu

Keyword(s):

Numerical Simulation ◽

Centrifugal Pump ◽

Flow Characteristics ◽

Internal Flow ◽

Tip Clearance ◽

Evolution Process ◽

And Performance ◽

Unsteady Numerical Simulation

AbstractTo study the influence of tip clearance on internal flow characteristics and external performance of a prototype centrifugal pump with a semi-open impeller, the unsteady numerical simulation and performance experiments are carried out in this paper. The evolution process of leakage vortex with time

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Internal Flow Characteristics of a Centrifugal Pump with Various Specific Speeds

The KSFM Journal of Fluid Machinery ◽

10.5293/kfma.2017.20.3.026 ◽

2017 ◽

Vol 20 (3) ◽

pp. 26-35

Author(s):

Hyeon-Seok Shim ◽

Kwang-Yong Kim ◽

Young-Seok Choi

Keyword(s):

Centrifugal Pump ◽

Flow Characteristics ◽

Internal Flow

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Numerical Study of Thermal and Flow Characteristics of Plate-Fin Heat Sink with Longitudinal Vortex Generator Installed on the Ground

Mathematical Problems in Engineering ◽

10.1155/2014/245759 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9

Author(s):

Yen-Tso Chang ◽

Han-Ching Lin ◽

Chi-Jui Huang ◽

Go-Long Tsai ◽

Jinn-Feng Jiang

Keyword(s):

Heat Sink ◽

Transient Flow ◽

Numerical Study ◽

Thermal Flux ◽

Flow Characteristics ◽

Vortex Generator ◽

Attack Angle ◽

Longitudinal Vortex ◽

Coolant Fluid ◽

Transverse Distance

This study applied the commercial software ANSYS CFD (FLUENT), for simulating the transient flow field and investigating the influence of each parameter of longitudinal vortex generators (LVGs) on the thermal flux of a plate-fin heat sink. Vortex generator was set in front of plate-fin heat sink and under the channel, which was in common-flow-down (CFD) and common-flow-up (CFU) conditions, which have the result of vortex generator of delta winglet pair (DWP). In this study the parameters were varied, such as the minimum transverse distance between winglet pair, the attack angle of the vortex generator, fins number, the fin height, and the distance between the vortex generator and plate-fin. The coolant fluid flew into the fin-to-fin channel and pushed the vortex from different geometry toward the bottom. This phenomenon took off the heat from the plate to enhance the heat transfer. The numerical results indicated that the LVGs located close to the plate-fin heat sink are zero with the attack angle being 30°, presenting optimal overall conditions.

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Numerical Simulation of the Transient Flow in a Centrifugal Pump during Regulating Period

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.268-270.1407 ◽

2011 ◽

Vol 268-270 ◽

pp. 1407-1410

Author(s):

Yue Tang ◽

Er Hui Liu ◽

Ling Di Tang ◽

Wang Hui

Keyword(s):

Fluid Flow ◽

Centrifugal Pump ◽

Moving Boundary ◽

Transient Flow ◽

Pressure Fluctuations ◽

Angular Acceleration ◽

Internal Flow ◽

Dynamic Mesh ◽

Hydrodynamic Performance ◽

State Process

Centrifugal pump performance has transient effect obviously during rapid changing period and the pump hydrodynamic performance of transient is different from steady-state process. In order to research the speed regulation characteristics and the inner flow mechanism of the centrifugal pump, numerical method of solving the unsteady fluid flow around the accelerating blade was established. The dynamical changes of the pressure and velocity were simulated by Fluent6.2, using standard k-epsilon turbulence model, PISO algorithm. The dynamic mesh technology and UDF were used to deal with the moving boundary caused by changing speed. Simulation results shown that faster angular acceleration made larger pressure fluctuations. Different regulated time had different influence in the system transient characteristics. And the evolution of the internal flow rate present strong transient performance in the regulating process. The study confirmed the feasibility of dynamic mesh method in solving the transient fluid flow during pump regulating period.

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Study and Investigation on the Mach of Impeller Outlet and Diffuser Inlet in Stamping and Welding Centrifugal Pump

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.229-231.2454 ◽

2012 ◽

Vol 229-231 ◽

pp. 2454-2458

Author(s):

Jian Jun Gan ◽

Jie Gang Mou ◽

Shui Hua Zheng ◽

Bo Zhu

Keyword(s):

Centrifugal Pump ◽

Experimental Research ◽

Static Pressure ◽

Flow Characteristics ◽

Internal Flow ◽

Area Ratio ◽

Cfd Simulations ◽

Impeller Outlet ◽

And Performance

Based on CFD simulations and experimental research, this paper studied the mach of impeller outlet and diffuser inlet in stamping and welding centrifugal pump. The influence of area ratio Y of impeller outlet to diffuser inlet on pump internal flow characteristics and performance was studied. Five different area ratio pump models were analyzed. The results indicate that as the area ratio Y= F3/F2 increase, the velocity of fluid in diffuser inlet decreases continuously, the average static pressure of diffuser outlet increases, and the head and efficiency of the pump are risen. When the area ratio increases from Y=1.48 to Y=3.49, the head increases about 3.0% and the efficiency about 2.0%.

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Computation of Viscous Flow Inside a Double-Channel Centrifugal Pump

The Open Mechanical Engineering Journal ◽

10.2174/1874155x01408010613 ◽

2014 ◽

Vol 8 (1) ◽

pp. 613-618

Author(s):

Su-Lu Zheng ◽

Xiang-Ping Wang ◽

Rui-Hang Zheng ◽

Ai-Ping Xia ◽

Yi-Nian Wang ◽

...

Keyword(s):

Viscous Flow ◽

Centrifugal Pump ◽

Design Method ◽

Pure Water ◽

Flow Characteristics ◽

Internal Flow ◽

Solid Particles ◽

Water Medium ◽

Centrifugal Pumps ◽

Double Channel

The double-channel centrifugal pumps are widely used to transport the two-phase flow including big solid particles in industry and agriculture. However, the related design theory and the design method are immature by far. In practice, the revised design method based on the pure water medium is still the main method for the solid-liquid twophase double-channel pump. Therefore, it is very necessary to deeply study the flow characteristics on the condition of the pure water medium. In this paper, in order to study the flow characteristics inside a prototype double-channel centrifugal pump in the case that the delivered medium is the pure water, the SIMPLE algorithm, RNG κ-ε turbulence model, and frozen rotor method are employed to calculate the incompressible, viscous, three-dimensional internal flow. The calculation results display the variation characteristics of the internal flow field and the external performance. The results show that the predicted pump head drops with the increasing flow rate, which manifest that the pump model is of good operation stability at the whole range of working. At the design point, a strong and large vortex remain appears at the middle section of the double-channel impeller. The computational fluids dynamic technology is competent to assess the internal viscous flow inside a double-channel centrifugal pump.

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Analysis of Unsteady Pressure Fluctuation in a Semi-Open Cutting Pump

Energies ◽

10.3390/en13143657 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3657

Author(s):

Weidong Cao ◽

Jiayu Mao ◽

Wei Li

Keyword(s):

Flow Rate ◽

Pressure Fluctuation ◽

Pressure Fluctuations ◽

Three Dimensional ◽

Flow Characteristics ◽

Internal Flow ◽

Lower Plate ◽

Pressure Distributions ◽

Axial Forces ◽

Blade Frequency

In order to understand the pressure fluctuation characteristics of a semi-open cutting pump, the three-dimensional unsteady flow fields were calculated. External and internal flow characteristics of four schemes with different relative angles between the rotary cutter and the impeller were studied. The pressure fluctuations in the lower plate, the upper plate, the clearance between the rotary cutter and the fixed cutter, the first section in volute and nearby parts of the tongue were all analyzed, which are all the places that pressure distributions are greatly affected by the static and dynamic interaction, and at the same time, the force on the impeller was also analyzed. The results show that the fluctuations at different positions change periodically; the main frequency is blade frequency. The amplitude of pressure fluctuation decreases from near the rotating part to far away, from near the tongue to far from the tongue. Due to the influence of both impeller and rotary cutter, the pressure fluctuation on the lower plate is the largest. The pressure fluctuation is affected by flow rate, the larger the flow rate, the greater the pressure fluctuation. The radial and axial forces of the impeller change periodically with time, and the number of wave peaks and wave valleys is the same as the number of blades.

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