Effects of Blade Outlet Width on Flow Field and Characteristic of Centrifugal Pumps

2009 ◽  
Author(s):  
Ming-gao Tan ◽  
Hou-lin Liu ◽  
Shou-qi Yuan ◽  
Yong Wang ◽  
Kai Wang
Keyword(s):  
Flow Field ◽  
Flow Curve ◽  
High Efficiency ◽  
Field Analysis ◽  
Centrifugal Pumps ◽  
Research Results ◽  
Rotor Stator Interaction ◽  
Nominal Condition ◽  
Specific Speed ◽  
Width Change

The present deficiency about numerical simulation research on blade outlet width of centrifugal pumps is pointed out. In the case of different outlet widths, the flow field in six centrifugal pumps whose specific speed vary from 45 to 260 are simulated by using commercial code FLUENT and the characteristics are predicted. The standard k-ε turbulence model and SIMPLEC algorithm are chosen in FLUENT. The simulation is steady and moving reference frame is used to consider rotor-stator interaction. The research results show that the change of impeller outlet width has obvious impacts on characteristics at design point, flow field and the shape of performance curves. At nominal condition, the change of outlet width has more important effects on moderate specific speed centrifugal pumps. The flow field analysis indicates that blade outlet width change has an important effect on the location and area of low pressure region behind the blade inlet, jet-wake structure in impellers, the secondary flow in volute cross section and the back flow in impellers. The head-flow curve becomes more flat with the increase of outlet width. For moderate and low specific speed centrifugal pumps, the high efficiency area of efficiency-flow curve get bigger with the increase of outlet width and the area will be constant within certain outlet width change scope for high specific speed centrifugal pump. The research results agree well with experiment results.

Prediction of the Effect of Impeller Trimming on the Hydraulic Performance of Low Specific-Speed Centrifugal Pumps

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
D. G. J. Detert Oude Weme ◽  
M. S. van der Schoot ◽  
N. P. Kruyt ◽  
E. J. J. van der Zijden
Keyword(s):  
Flow Field ◽  
Prediction Method ◽  
Hydraulic Performance ◽  
New Method ◽  
Prediction Methods ◽  
Centrifugal Pumps ◽  
Flow Rates ◽  
Pump Head ◽  
Low Specific Speed ◽  
Specific Speed

The effect of trimming of radial impellers on the hydraulic performance of low specific-speed centrifugal pumps is studied. Prediction methods from literature, together with a new prediction method that is based on the simplified description of the flow field in the impeller, are used to quantify the effect of trimming on the hydraulic performance. The predictions by these methods are compared to measured effects of trimming on the hydraulic performance for an extensive set of pumps for flow rates in the range of 80% to 110% of the best efficiency point. Of the considered methods, the new prediction method is more accurate (even for a large impeller trim of 12%) than the considered methods from literature. The new method generally overestimates the reduction in the pump head after trimming, and hence results less often in impeller trims that are too large when the method is used to determine the amount of trimming that is necessary in order to attain a specified head.

The effect of wear ring clearance on flow field in the impeller sidewall gap and efficiency of a low specific speed centrifugal pump

2017 ◽  
Vol 232 (17) ◽  
pp. 3062-3073 ◽  
Author(s):  
M DaqiqShirazi ◽  
R Torabi ◽  
A Riasi ◽  
SA Nourbakhsh
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Volumetric Efficiency ◽  
Centrifugal Pumps ◽  
Disk Friction ◽  
Low Specific Speed ◽  
Overall Efficiency ◽  
Specific Speed

In this paper, the flow in the impeller sidewall gap of a low specific speed centrifugal pump is analyzed to study the effect of wear ring clearance and the resultant through-flow on flow field in this cavity and investigate the overall efficiency of the pump. Centrifugal pumps are commonly subject to a reduction in the flow rate and volumetric efficiency due to abrasive liquids or working conditions, since the wear rings are progressively worn, the internal leakage flow is increased. In the new operating point, the overall efficiency of the pump cannot be predicted simply by using the pump characteristic curves. The flow field is simulated with the use of computational fluid dynamics and the three-dimensional full Navier–Stokes equations are solved using CFX software. In order to verify the numerical simulations, static pressure field in volute casing and pump performance curves are compared with the experimental measurements. The results show that, for the pump with minimum wear ring clearance, the disk friction efficiency is the strongest factor that impairs the overall efficiency. Therefore, when the ring clearance is enlarged more than three times, although volumetric efficiency decreases effectively but the reduction in overall efficiency is remarkably smaller due to improvement in the disk friction losses.

scholarly journals On optimization of flow passages of impellers of centrifugal pumps

2019 ◽  
Vol 11 (4) ◽  
pp. 311-318
Author(s):  
A. V. Volkov ◽  
A. G. Parygin ◽  
A. A. Vikhlyantsev ◽  
A. A. Druzhinin
Keyword(s):  
High Efficiency ◽  
Modular Design ◽  
Energy Performance ◽  
High Energy ◽  
Experiment Planning ◽  
Centrifugal Pumps ◽  
Hydraulic Machines ◽  
Specific Speed ◽  
Conventional Solution ◽  
Turbine Mode

The conventional solution for HAPPs is the use of reversible hydraulic machines operating both in the pump mode as well as in the turbine mode. At the same time, for example, a blade system of a hydraulic machine designed for the pumping mode has a high efficiency. However, in the turbine mode, the energy characteristics of such machine are far from optimal. Considering different patterns of micro- and mini-HAPPs (up to 100 kW) of modular design, it is most appropriate to use a pump and a turbine separately, since the efficiency of hydraulic machines is very important in the case of such low power. To date, approaches to the design of hydraulic turbines are quite developed and allow to achieve high energy performance [1, 2]. According to different data sources the level of axial turbine efficiency with power less than 100 kW is about 80÷91%. At the same time, for centrifugal pumps, especially those of low specific speed, the problem of increasing energy efficiency is very urgent. E.g., for pumps with a specific speed ns< 80 the efficiency level is usually 40 to 65%. The aim of the presented research is the development of methods of synthesis and optimization of the flow passages of centrifugal pumps using the approaches of the theory of optimal control and increasing energy performance of hydraulic machines. Various ways of local correction of geometry of flow passages are presented in the paper. As an alternative to empirical approaches, methods based on the control of the circulation distribution are considered in detail. Various mathematical dependences of the flow circulation on the coordinate of the point lying on the surface of the blade are analyzed. Possibilities of application of the theory of experiment planning in relation to the problems to be solved are considered.

The action mechanism of rotor–stator interaction on the hydraulic and hydroacoustic characteristics of the guide vane in a jet centrifugal pump

2020 ◽  
Vol 34 (34) ◽  
pp. 2050396
Author(s):  
Rong Guo ◽  
Rennian Li ◽  
Renhui Zhang ◽  
Wei Han
Keyword(s):  
Flow Field ◽  
Transient Flow ◽  
Guide Vane ◽  
Centrifugal Pumps ◽  
Action Mechanism ◽  
Exterior Field ◽  
Outlet Angle ◽  
Rotor Stator Interaction ◽  
Wrap Angle ◽  
Hydrodynamic Noise

The aim of this study was to investigate the action mechanism of the rotor–stator interaction (RSI) in the transient flow field and hydrodynamic noise field of the guide vane in jet centrifugal pumps (JCPs). The numerical method of CFD (computational fluid dynamics), coupled with CFA (computational fluid acoustics), was used to analyze the correlation between the impeller parameters and the flow/sound characteristics of the guide vane. The results show that on the inlet surface of the guide vane, an impeller with fewer blades, a smaller wrap angle, a smaller outlet angle and a smaller outlet diameter is beneficial for reducing the pressure fluctuation intensity. When the guide vane geometry is constant, the evolution processes of the transient flow field inside the static and dynamic cascades are mainly related to the blade number and speed of the impeller. An impeller with more blades, a larger wrap angle, a smaller outlet angle and a smaller outlet diameter is beneficial for improving the flow field distribution in the dynamic and static cascades. The hydrodynamic noise in the interior field is mainly related to the fluctuation characteristics of the transient flow field, but that in the exterior field is related not only to the fluctuation characteristics of the transient flow field, but also to the structural properties of the JCP pump body. The hydrodynamic noise in the exterior field presents an obvious dipole symmetrical distribution on the meridional plane, and the minimum value appears in the direction of the rotation axis because of the symmetrical structural characteristics of the pump body. The modal-shaped features of the JCP lead to a sidelobe phenomenon on the sagittal plane.

Experimental Studies on the Optimization Design of a Low Specific Speed Centrifugal Pump

2011 ◽  
Author(s):  
Jinfeng Zhang ◽  
Ye Yuan ◽  
Shouqi Yuan ◽  
Weigang Lu ◽  
Jianping Yuan
Keyword(s):  
Neural Network ◽  
Centrifugal Pump ◽  
Network Model ◽  
High Efficiency ◽  
Experimental Studies ◽  
Test Scheme ◽  
Centrifugal Pumps ◽  
Marquardt Algorithm ◽  
Low Specific Speed ◽  
Specific Speed

For a low specific speed centrifugal pump with the requirement of high efficiency of 68% and non-overload power characteristics, series experimental studies, by matching 9 volutes with 19 impellers were done. By combining the former research results about the splitters and the non-overload theory in centrifugal pump, the theoretical conditions to achieve the property of non-overload in a centrifugal pump with splitters was analyzed, and formulas to estimate the maximum shaft power and its position are derived. Based on the requirement of high efficiency and non-overload, blade outlet angle β2, blade outlet width b2, volute throat are Ft and the inlet diameter of splitters Di were chosen with three levels to design a normal L9 (34) orthogonal test scheme. After the optimized design scheme was determined, and corresponding test was done also, it demonstrates that the experiment purpose was achieved and the design method to combine the splitters and non-overload theory is reasonable, which can get the property of high efficiency and non-overload. A BP artificial neural network (BPANN) model was built to predict the efficiency and head of centrifugal pumps with splitters in MATLAB toolbox. Eighty five groups of test results were used to train and test the network model, where the Levenberg–Marquardt algorithm was adopted to train the neural network model. Five parameters Q, Z, β2, Di, b2 were chosen as the input layer parameters, η and H were the output factors. Through the analysis of prediction results, the conclusion was got that, the accuracy of the BP ANN is good enough for performance prediction. And the BP ANN can be used for assisting design of centrifugal pumps with splitters, which can shorten research time and cost.

The Influence of Supersonic Combustion when the Cavity Parameters Changed on the Chamber Wall

2012 ◽  
Vol 468-471 ◽  
pp. 2620-2623
Author(s):  
Peng Gao ◽  
Xin Long Chang ◽  
Shuang Lin Gao ◽  
Jie Tang Zhu
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
High Efficiency ◽  
Supersonic Combustion ◽  
Chamber Wall ◽  
Flame Stability ◽  
Hydrogen Fuel ◽  
Research Results ◽  
Scramjet Combustor ◽  
Air Mixing

In this paper, the detail numerical simulations were performed on the flow field of the scramjet combustor chamber with the hydrogen fuel, when the cavity parameters changed. The research results indicate that the effect of gas and air mixing and flame stability are altered when the parameter of cavity changed. From the research we will better understand the supersonic combustion. The high efficiency flame stabilities can be designed in future.

Hydrodynamic Efficiency Improvement of High-Specific-Speed Centrifugal Pump Impeller

2013 ◽  
Vol 467 ◽  
pp. 461-465 ◽  
Author(s):  
Chin Ting Yang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Efficiency ◽  
Maximum Flow ◽  
Performance Measurement System ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Frictional Loss ◽  
Specific Speed

The high-specific-speed centrifugal pumps are very common in industrial factory for transporting fluids all day long. However, oversized pumps with low performance still could meet the purpose of fluid transporting. The aim of this study was to reduce the existed commercial impeller energy consumption by optimizing the performance of impeller through CAE processes. The impeller model was first generated by BladeGen software and analyzed by CFX in Turbo-mode. The optimized model then exported to machine center to cut the precise aluminum mold. A regular sand die casting processes were used to manufacture the impeller. The original pump which only impeller was replaced with the new one was tested with performance measurement system again. The results show that when the mass flow rate between 40-90kg/s the CFD software predicted very well pump heads and efficiencies with experimental data, which was called optimized impeller. But around the minimum and maximum flow rate region, the recirculation flow between blades and frictional loss model used still need further investigation to shrink the difference. Compare to the original impeller, the optimized one had increased efficiency 6% at the mass flow rate of 80kg/s. Also the high efficiency region (nearby of BEP) of the new impeller had broadened 50%. And the maximum mass flow rate increased 13% than the original one.

scholarly journals Experimental and Numerical Investigation of Pressure Fluctuation in a Low-Specific-Speed Centrifugal Pump with a Gap Drainage Impeller

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Li Zhang ◽  
Hui Li ◽  
Hong Xu ◽  
Weidong Shi ◽  
Yang Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Pressure Pulsation ◽  
Internal Flow ◽  
Stable Operation ◽  
Simulation Methods ◽  
Centrifugal Pumps ◽  
Numerical Simulation Methods ◽  
Low Specific Speed ◽  
Specific Speed

In order to analyze the effect of impeller with different slot widths on the performance of the low-specific-speed centrifugal pumps, based on the impeller of a single-stage pump with the specific speed of 21, two gap drainage schemes with slot widths of 1.5 mm and 6.0 mm, slot diameter of 180 mm, and lap length of 5 mm were designed. Both experimental and numerical simulation methods were applied to compare the steady performance, which includes the head, efficiency, and the internal flow field distribution, and the unsteady pressure pulsation performance between new designed pumps and the original pump. The results show that gap drainage would cause a certain degree of head reduction, but a smaller slot width could achieve higher efficiency. Meanwhile, a reasonable open seam scheme can reduce the development of pressure pulsation, which provides experience and reference for the stable operation of low-specific-speed centrifugal pumps.

scholarly journals Effect of Short Blade Circumferential Position Arrangement on Gas-Liquid Two-Phase Flow Performance of Centrifugal Pump

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1317
Author(s):  
Biaobiao Wang ◽  
Haoyang Zhang ◽  
Fanjie Deng ◽  
Chenguang Wang ◽  
Qiaorui Si
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Two Phase Flow ◽  
Low Flow ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Suction Surface ◽  
Two Phase ◽  
Low Specific Speed ◽  
Specific Speed

In order to study the internal flow characteristics of centrifugal pumps with a split impeller under gas-liquid mixed transportation conditions, this paper conducted a steady calculation of the flow field in the centrifugal pump under the conditions of different inlet gas volume fractions based on the Eulerian-Eulerian heterogeneous flow model, using air and water as the working media and the Schiller Nauman model for the interphase resistance. This paper takes a low specific speed centrifugal pump as the research object, through the controlling variables, using the same pump body structure and pump body geometric parameters and setting three different arrangements of long and short blades (each plan uses the same long and short blades) to explore the influence of the short blade arrangement on the low specific speed centrifugal pump performance under a gas-liquid two-phase flow. The research results show that, under pure water conditions, the reasonable arrangement of the short blade circumferential position can eliminate the hump of the centrifugal pump under low-flow conditions, can make the flow velocity in the impeller more uniform, and can optimize the performance of the pump. Under the design conditions and the gas-liquid two-phase inflow conditions, when the circumferential position of the short blades is close to the suction surface of the long blades, some of the bubbles on the suction surface of the long blade can be broken under the work of the pressure surface of the short blade and flow out of the impeller with the liquid, which improves the flow state of the flow field in the impeller.

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