Closure to “Discussion of ‘Behavior of Air Bubbles in an Axial-Flow Pump Impeller’” (1983, ASME J. Fluids Eng., 105, p. 283)

1983 ◽  
Vol 105 (3) ◽  
pp. 283-283
Author(s):  
M. Murakami ◽  
K. Minemura
Keyword(s):  
Axial Flow ◽  
Air Bubbles ◽  
Pump Impeller ◽  
Axial Flow Pump ◽  
Flow Pump

Behavior of Air Bubbles in an Axial-Flow Pump Impeller

1983 ◽  
Vol 105 (3) ◽  
pp. 277-283 ◽  
Author(s):  
M. Murakami ◽  
K. Minemura
Keyword(s):  
Bubble Diameter ◽  
Three Dimensional ◽  
Axial Flow ◽  
Air Bubbles ◽  
Bubble Motion ◽  
Three Dimensional Flow ◽  
Surrounding Water ◽  
Pump Impeller ◽  
Axial Flow Pump ◽  
Flow Pump

Motion of air bubbles in a high-specific-speed axial-flow pump impeller was analyzed on the basis of measured streak lines of air bubbles in the impeller. The results were compared with those obtained by a numerical solution of the bubble motion equations for three dimensional flow. Governing factors of the bubble motion are the drag force due to the surrounding water and the force due to the pressure gradient. Trajectories of the bubbles deviate somewhat from the streamlines of water, and the amount of the deviation is dependent on the bubble diameter and also on specific-speeds of the pumps and flow rate of water.

scholarly journals Study on the Performance Improvement of Axial Flow Pump’s Saddle Zone by Using a Double Inlet Nozzle

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1493
Author(s):  
Weidong Cao ◽  
Wei Li
Keyword(s):  
Flow Rate ◽  
Three Dimensional ◽  
Axial Flow ◽  
Rotating Stall ◽  
Stable Operation ◽  
Inlet Section ◽  
Pump Impeller ◽  
Rate Condition ◽  
Axial Flow Pump ◽  
Flow Pump

The operating range of axial flow pumps is often constrained by the onset of rotating stall. An improved method using a double inlet nozzle to stabilize the performance curve is presented in the current study; a single inlet nozzle and three kinds of double inlet nozzle with different rib gap widths at the inlet of axial flow pump impeller were designed. Three dimensional (3D) incompressible flow fields were simulated, and the distributions of turbulence kinetic energy and velocity at different flow rates located at the inlet section, as well as the pressure and streamline in the impeller, were obtained at the same time. The single inlet nozzle scheme and a double inlet nozzle scheme were studied; the experimental and numerical performance results show that although the cross section is partly blocked in the double inlet nozzle, the head and efficiency do not decline at stable operation flow rate. On small flow rate condition, the double inlet nozzle scheme effectively stabilized the head-flow performance, whereby the block induced by the backflow before the impeller was markedly improved by using a double inlet nozzle. It has also been found that the rib gap width impacts the efficiency curve of the axial flow pump.

An Investigation of the Vortex in a Submersible Axial Flow Pump Impeller

2015 ◽  
Vol 741 ◽  
pp. 481-485
Author(s):  
Hong Ming Zhang ◽  
Li Xiang Zhang
Keyword(s):  
Pressure Pulsation ◽  
Axial Flow ◽  
Suction Side ◽  
Transfer Model ◽  
Mass Transfer Model ◽  
Governing Equations ◽  
Pump Impeller ◽  
Axial Flow Pump ◽  
Volume Method ◽  
Flow Pump

The paper presents numerical simulation of the vortex in a submersible axial flow pump impeller using OpenFoam code. A mixture assumption and a finite rate mass transfer model were introduced to analyze vortex. The finite volume method is used to solve the governing equations of the mixture model and the pressure-velocity coupling is handled via a Pressure Implicit with Splitting of Operators (PISO) procedure. Simulation results have shown that the cavitation may occur on the lower portion of impeller suction side. And the blade channel vortex will be formed in the impeller. It can induce the pressure pulsation in the impeller and can result in reduced efficiency of the submersible axial flow pump.

NPSHr Optimization of Axial-Flow Pumps

2008 ◽  
Vol 130 (7) ◽  
Author(s):  
Wen-Guang Li
Keyword(s):  
Axial Flow ◽  
Wind Tunnels ◽  
Step Method ◽  
Pump Impeller ◽  
Impeller Blade ◽  
Impeller Outlet ◽  
Axial Flow Pump ◽  
Velocity Moment ◽  
Two Parameters ◽  
Flow Pump

The two-step method for optimizing net positive suction head required (NPSHr) of axial-flow pumps is proposed in this paper. First, the NPSHr at the impeller tip is optimized with impeller diameter based on experimental data of 2D cascades in available wind tunnels. Then, it is optimized again with the velocity moment at the impeller outlet, which is expressed in terms of two parameters. The blade geometry is generated and flow details are clarified by using the radial equilibrium equation, actuator disk theory, and 2D vortex element method in the optimizing process. The NPSHr response surface has been established in terms of these two parameters. The results illustrate that the second optimization allows NPSHr to be reduced by 37.5% compared to the first optimization. Therefore, this two-step method is effective and expects to be applied in the axial-flow pump impeller blade design. The simulations of 3D turbulent flow with various cavitation models and related confirming experiments are going to be done in the axial-flow impellers designed with this method.

scholarly journals Analysis of Centroid Trajectory Characteristics of Axial-Flow Pump Impeller Under Hydraulic Excitation

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaohui Duan ◽  
Fangpin Tang ◽  
Hao Xu ◽  
Jian Chen ◽  
Qun Lu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Field Test ◽  
Water Pressure ◽  
Axial Flow ◽  
Pump Unit ◽  
Pump Impeller ◽  
Time Frequency ◽  
Axial Flow Pump ◽  
Flow Pump

The hydraulic excitation characteristics of axial flow pump unit are studied through theoretical analysis, numerical simulation and field test in this paper. The correlation between impeller hydraulic and radial vibration displacement of impeller centroid is obtained through theoretical analysis. Through the 1-way fluid-solid-interaction (FSI) numerical simulation, the distributions of water pressure and displacement on the impeller surface are obtained, and the time-domain and frequency-domain characteristics of transient hydraulic and radial displacement are revealed. Through the field test, the external characteristics of axial flow pump unit and the time-frequency characteristics of the pressure pulsation at the measuring points beside the inlet of the impeller are obtained. The comparisons between simulation results and experimental results show that the former is accurate and reliable.

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