Transient Characteristics of a Centrifugal Pump at Rapid Startup

2019 ◽  
Author(s):  
Teiichi Tanaka ◽  
Michiya Tabaru
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Thrust Force ◽  
Experimental Results ◽  
Operating Point ◽  
Axial Thrust ◽  
Transient Characteristics ◽  
Transient Period ◽  
Large Flow

Abstract Experimental and CFD studies were carried out on transient behavior of a centrifugal pump at rapid startup. Relationship between the transient characteristics and a flow field in the centrifugal pump was investigated during transient period of the centrifugal pump from experimental results. A single-stage, volute type centrifugal pump is used for the experiments. The pump is equipped with transparent impeller, casing, suction pipe and discharge pipe for PIV in the future. The test setup is a closed-loop and consists of a suction tank, a test pump, an ultrasonic flow meter and a flow control valve. Instantaneous pressure and flow rate were measured at suction and discharge ports with rotational speed during the transient period. The pump suction and delivery pressures were measured using strain gauge type pressure transducers. Unsteady flow rate was calculated from pressure difference between two pressure measurement points in straight pipe of the pump suction lines using the difference of inertia force. The three-dimensional incompressible flow calculation of the test pump is performed using ANSYS® CFX 17.1. The CFD domain is consisted of a pump suction pipe, a pump casing, an impeller and a pump delivery pipe. For all computations, a block structure mesh of around 1,550,000 elements has been used. The mesh is created with the mesh generator ANSYS® ICEM CFD Ver.17.1. Frozen Rotor Method is used for the steady state calculation, and Transient Rotor Method is used for the unsteady calculation. The standard SST model is used for turbulence modelling. Boundary conditions of the pump inlet and outlet are used the time history of total head and mass flow rate obtained from experiment result, respectively. The variation of pump operating point, torque and axial thrust force during transient period were related to the time-dependent flow field, which was investigated using CFD, in the pump. As results of the present study, it was shown that the pump operating point in experiment were larger than quasi-steady one at early transient stage, and then the pump operating point reaches to quasi-steady one. CFD results indicated similar tendency to experimental results on the variation of the pump operating point. Moreover, variation of the torque and axial thrust force during transient period also indicated deviation from each quasi-steady change. From the experimental and CFD results, the deviation of pump operating point, torque and axial thrust force from the quasi-steady change during pump startup period occurs at a large flow rate acceleration. The reason is thought to be due to that the flow field at large flow rate change cannot develop compared with that at the quasi-steady change.

Principle and structure of a multi-chamber piezoelectric pump with large flow rate integrated into printed circuit board

2022 ◽  
pp. 1045389X2110721
Author(s):  
Yun-Hao Peng ◽  
Dai-Hua Wang ◽  
Lian-Kai Tang
Keyword(s):  
Flow Rate ◽  
Compression Ratio ◽  
Layer Structure ◽  
Experimental Results ◽  
Processing Technology ◽  
Rate Model ◽  
Piezoelectric Pump ◽  
Central Deflection ◽  
Maximum Value ◽  
Large Flow

Parametric simulation of multi-chamber piezoelectric pump proposed by authors shows that its flow rate is positively correlated with chamber compression ratio when height of chamber wall is not less than central deflection of circular piezoelectric unimorph actuator (CPUA). Therefore, in this paper, principle and structure of multi-chamber piezoelectric pump with novel CPUAs with three-layer structure are proposed and realized, so as to improve its chamber compression ratio, and then improve its flow rate. Its processing technology compatible with PCB processing technology is studied and its flow rate model is established. Central deflection of CPUA with three-layer structure and the flow rate characteristics are tested. Experimental results show that when the central deflection of CPUA with three-layer structure reaches the maximum value of 106.8 μm, the chamber compression ratio and flow rate of multi-chamber piezoelectric pump reach the maximum value of 50% and 3.11 mL/min, respectively. The maximum flow rate is increased by 622% compared to unimproved pump. By comparing experimental results with numerical and finite element simulation results, the realized multi-chamber piezoelectric pump has large flow rate and the established flow rate model can predict its flow rate.

scholarly journals Two Dimensional Flow Analysis of a Laboratory Centrifugal Pump

1990 ◽  
Author(s):  
S. M. Miner ◽  
R. D. Flack ◽  
P. E. Allaire
Keyword(s):  
Velocity Field ◽  
Stagnation Point ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Flow Analysis ◽  
Tangential Component ◽  
Design Flow ◽  
Experimental Results ◽  
Two Dimensional ◽  
Flow Angle

Two dimensional potential flow was used to determine the velocity field within a laboratory centrifugal pump. In particular, the finite element technique was used to model the impeller and volute simultaneously. The rotation of the impeller within the volute was simulated by using steady state solutions with the impeller in 10 different angular orientations. This allowed the interaction between the impeller and the volute to develop naturally as a result of the solution. The results for the complete pump model showed that there are circumferential asymmetries in the velocity field, even at the design flow rate. Differences in the relative velocity components were as large as 0.12 m/sec for the radial component and 0.38 m/sec for the tangential component, at the impeller exit. The magnitude of these variations was roughly 25% of the magnitude of the average radial and tangential velocities at the impeller exit. These asymmetries were even more pronounced at off design flow rates. The velocity field was also used to determine the location of the tongue stagnation point and to calculate the slip within the impeller. The stagnation point moved from the discharge side of the tongue to the impeller side of the tongue, as the flow rate increased from below design flow to above design flow. At design flow, values of slip ranged from 0.96 to 0.71, from impeller inlet to impeller exit. For all three types of data (velocity profiles, stagnation point location, and slip factor) comparison was made to laser velocimeter data, taken for the same pump. At the design flow, the computational and experimental results agreed to within 17% for the velocity magnitude, and 2° for the flow angle. The stagnation point locations coincided for the computational and experimental results, and the values for slip agreed to within 10%.

Periodically Unsteady Flow in a Single-Blade Centrifugal Pump: Numerical and Experimental Results

2005 ◽  
Author(s):  
F.-K. Benra ◽  
H. J. Dohmen ◽  
M. Sommer
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Sewage Water ◽  
Numerical Results ◽  
Experimental Results ◽  
Time Dependent ◽  
Pump Operation ◽  
Wide Range ◽  
Operating Points

The composition of sewage water with partially large portions of fibers and solids requires a special pump design, in order to avoid operational disturbances by clogging. In most applications for sewage water transport, single-stage pumps with single-blade impellers are used. With this special impeller geometry largest flow channels can be realized. So fibers and solids up to an appropriate size can be transported by the pump. This minimum impeller blade number however brings disadvantages for pump operation. The development of a pressure and a suction surface of the blade gives an asymmetric pressure distribution at the perimeter of the rotor outlet and a periodically unsteady flow field arises. In a numerical approach the time accurate flow in a single-blade centrifugal pump has been calculated by solving the 3-dimensional time dependent Reynolds averaged Navier-Stokes equations (URANS) in a wide range of pump operation. The investigation of the flow included all details between suction flange and pressure flange of the pump. The numerical results show a strong dependence from impeller position for all flow parameters. For the investigated operating points strong vortices have been obtained at particular impeller positions. Experimental results have been used to verify the numerical results of time dependent flow in the single-blade pump. The computed flow field has been compared to results which were obtained from optical measurements of flow velocities by Particle Image Velocimetry at different impeller positions. A very good qualitative agreement between measurements and calculations has been obtained for all investigated operating points.

Numerical Study of a Fuel Centrifugal Pump with Variable Impeller Width for Aero-engines

2015 ◽  
Vol 32 (4) ◽  
Author(s):  
Bin Wang ◽  
Huasheng Guan ◽  
Zhifeng Ye
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Numerical Study ◽  
High Reliability ◽  
Low Flow ◽  
Centrifugal Pumps ◽  
Fuel Temperature ◽  
Low Efficiency ◽  
Aero Engines ◽  
Large Flow

AbstractAs typical pump with large flow rate and high reliability, centrifugal pumps in fuel system of aero-engines mostly regulate flow rate by flow bypass, which leads to low efficiency and large fuel temperature rise especially at low flow rate. An innovative fuel centrifugal pump with variable impeller width is a more effective way to regulate flow rate than flow bypass. To find external characteristics of the centrifugal pump with variable impeller width proposed in this paper, flow domain within the pump is simulated numerically and some primary performance parameters and their correlation are analyzed. Results show that flow rate of the pump can be regulated by variable impeller width and that efficiency for this scheme is higher than that for flow bypass. The higher outlet static pressure the pump runs at, the wider range of flow rates can be obtained with stronger nonlinear relationship between flow rate and impeller width.

Measurements of Axial and Radial Thrust Forces Working on a Three-Stages Centrifugal Pump Rotor

2015 ◽  
Author(s):  
Tetsuya Yamashita ◽  
Satoshi Watanabe ◽  
Yoshinori Hara ◽  
Hiroyoshi Watanabe ◽  
Kazuyoshi Miyagawa
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Axial Direction ◽  
Low Flow ◽  
Axial Thrust ◽  
Rate Range ◽  
Wide Range ◽  
Flow Rate Range ◽  
Three Stages ◽  
Thrust Forces

In this study, radial and axial thrust forces working on the whole rotor in a three-stages centrifugal pump are measured in a wide range of flow rate. The forces are measured at two floating journal bearings and one floating ball bearing, which are supported by the individual load cells. The effects of the offset of rotor position in the axial direction on the thrust forces are investigated. It is found that the effect of the axial offset is significant for the axial thrust force in the low flow rate range, whereas it has little influence on the head and efficiency performances in the whole flow rate range.

scholarly journals Influence of Balance Hole Diameter on Leakage Flow of the Balance Chamber in a Centrifugal Pump

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wei Dong ◽  
Diyi Chen ◽  
Jian Sun ◽  
Yan Dong ◽  
Zhenbiao Yang ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Axial Force ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Vortex Motion ◽  
Internal Flow ◽  
Hole Diameter ◽  
Leakage Flow ◽  
Centrifugal Pumps ◽  
Axial Thrust

The balancing holes in centrifugal pumps with seals mounted in both suction and discharge sides are one of the approaches used by pump manufacturers to reduce the axial thrust. The balance hole diameter directly affects the axial force of the centrifugal pump. The flow characteristics in the balance chamber are closely related to the balance hole diameter. However, research is not very clear on the internal flow of the balanced chamber, due to the small axial and radial sizes and the complicated flow conditions in the chamber. In this paper, we analyzed the influence of the balance hole diameter on the liquid leakage rate, flow velocity, and vortex motion in the balance chamber. The results indicated that when the balance hole diameter was lower than the design value, the volume flow rate of leakage flow was proportional to the diameter. The liquid flow rate and vortex distribution rules in the balance chamber were mainly associated with the coeffect of radial leakage flow in the rear sealing ring interval and the axial balance hole leakage flow. The research has revealed the mechanisms of leakage flow of the balance chamber in the centrifugal pump and that this is of great significance for accurate calculation and balancing of the axial force.

scholarly journals Design and Manufacture of a Water Pump to Study the Effect of Impeller Blades Number on the Pump Performance

2021 ◽  
Vol 2 (2) ◽  
pp. 1-9
Author(s):  
Abdlmanam Elmaryami ◽  
Abdulla Sousi ◽  
Magdi E. M. El-Garoshi ◽  
Abdelkareem Aljair ◽  
Ahmed Almasry ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Experimental Results ◽  
Water Pump ◽  
Velocity Head ◽  
Pump Performance ◽  
Design And Manufacture

In this study, the flow rate, velocity, head, and power in a designed and manufactured centrifugal water pump were studied and determined experimentally. The effect of the impeller with different blades on the centrifugal pump performance has been investigated. Three different impellers with 4, 5, and 6 blades are tested to determine the number of the optimum blades. The experimental results showed that the flow rate, velocity, heat, and power are higher for the case of the impeller with 6 blades than that for the two cases of 4 and 5 blades. The losses decrease by increasing the number of the blades due to the reduction of the secondary flow for a certain limit. The experimental results showed better centrifugal water pump performance when an impeller with 6 blades is used.

scholarly journals Effect of Blade Outlet Angle on Unsteady Hydrodynamic Force of Closed-Type Centrifugal Pump with Single Blade

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Yasuyuki Nishi ◽  
Junichiro Fukutomi
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Static Pressure ◽  
Hydrodynamic Forces ◽  
Centrifugal Impeller ◽  
Leakage Flow ◽  
Axial Thrust ◽  
Outlet Angle ◽  
Closed Type ◽  
Radial Thrust

Geometrically, the single-blade centrifugal impeller, commonly used today as a sewage pump, is not axially symmetric. For this reason, the static pressure around the impeller fluctuates greatly when the impeller is rotating, and not only the radial thrust but also the axial thrust shows large fluctuations. Therefore, it is extremely important for the improvement of pump reliability to quantitatively grasp these fluctuating hydrodynamic forces. In this study, we investigated the unsteady hydrodynamic forces in a closed-type centrifugal pump with a single blade for different blade outlet angles using a numerical analysis that takes into account both experiment and the leakage flow. The results clearly showed the effect of the blade outlet angle on that act on the impeller. The root-mean-square value of the fluctuating component of the total radial thrust was roughly the same for whichever impeller at low flow rate, but at high flow rates, the value increased for impellers with larger blade outlet angles. Moreover, when the leakage flow rate increased with increasing static pressure around the impeller, such that the rear and front shroud parts were subject to high pressure, the absolute value of the axial thrust on both these parts increased.

Numerical Investigation on the Stage Matching in a Multi-Stage Centrifugal Compressor

2014 ◽  
Author(s):  
Pengfei Zhang ◽  
Zhiheng Wang ◽  
Wenlong Duan ◽  
Guang Xi
Keyword(s):  
Flow Rate ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Axial Thrust ◽  
Large Flow Rate ◽  
Multi Stage ◽  
Overall Performance ◽  
Stage Matching ◽  
The Individual ◽  
Large Flow

The performance of a multi-stage centrifugal compressor is commonly generated by stacking the individual stage’s performance in the industry applications, which makes the proper stage matching vital in getting favorable performance of the whole machine. Taking a two-stage centrifugal refrigeration compressor as the research object, this paper numerically investigates the two key problems in the stage matching, i.e. 1) The accuracy of overall performance generated by stacking the individual stages’ performance; 2) Effects of the inlet and outlet flow distortions on the individual stage performance and the axial thrust. It is found that the overall performance of the multi-stage centrifugal compressor predicted by the stage-stacking method generally agrees well with that predicted by the CFD analysis at the small and moderate flow rates, and the difference is getting bigger at the large flow rate. The numerical investigations also show that the effect of inlet distortion on the isentropic efficiency and the total pressure ratio exist mainly at the large flow rate. The radial distortion of the inflow has little influence on the performance, while the circumferential distortion of the inflow affects remarkably. The outlet distortion also has an important influence on the performance of upstream stage. The effect of flow distortions at the inlet and outlet on the impeller thrust is presented as well.

Numerical and Experimental Investigation of Performance and Reliability in New Reverse Osmosis Seawater Desalination High Pressure Pump

2013 ◽  
Author(s):  
Xiao-yan Ye ◽  
Jing-ning Hu ◽  
Jing Wang ◽  
Yao-ning Feng ◽  
Wei Jiang
Keyword(s):  
High Pressure ◽  
Centrifugal Pump ◽  
Reverse Osmosis ◽  
Experimental Results ◽  
Seawater Desalination ◽  
Axial Thrust ◽  
High Pressure Pump ◽  
Pressure Pump ◽  
Multistage Pump ◽  
The Relationship

In order to reduce the investment cost and energy consumption of high pressure pump in Seawater Reverse Osmosis desalination project, a new type of multistage high pressure centrifugal pump with two ends of water-lubricated bearings supporting and axial suction was proposed after analyzing the structural feature of the high pressure pump. The numerical simulation method and mesh quality was improved, the pump performance was predicted and optimized. The relationship of the critical speed and logarithmic decay rate with stage was analyzed, and the relationship between the stage and efficiency of multistage pump was combined to analyze the optimal selection for the impeller stages of multistage pump. The experimental results of axial thrust were used to modify theoretical formula of axial thrust and accurately predicated the axial thrust at different operating conditions. A new balancing device with less leakage fluid, high balancing sensitivity and proper restoring force was designed to improve the reliability of axial thrust balancing device. The experimental results show that the efficiency of the new multistage high pressure centrifugal pump is 83.07% which is increased by 3.07 percents when the design flow rate is 220m3/h, and total Head is 620m. The new multistage high pressure centrifugal pump has been applied in the Chinese Zhoushan seawater desalination project, which runs with high efficiency and stability.

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