Abstract

Complete pump characteristics (CPCs) are the key for establishing pump boundary conditions and simulating hydraulic transients. However, they are not normally available from manufacturers, making pump station design difficult to carry out. To solve this issue, a novel method considering the inherent operating characteristics of the centrifugal pump is therefore proposed to predict the CPCs. First, depending on the Euler equations and the velocity triangles at the pump impeller, a mathematical model describing the complete characteristics of a centrifugal pump is deduced. Then, based on multiple measured CPCs, the nonlinear functional relationship between the characteristic parameters of the characteristic operating points (COPs) and the specific speed is established. Finally, by combining the mathematical model with the nonlinear relationship, the CPCs for a given specific speed are successfully predicted. A case study shows that the predicted CPCs are basically consistent with the measured data, showing a high prediction accuracy. For a pump-failure water hammer, the simulated results using the predicted CPCs are close to that using the measured data with a small deviation. This method is easy to program and the prediction accuracy meets the requirements for hydraulic transient simulations, providing important data support for engineering design.

Highlights

  • Due to its wide range of flow and head, a centrifugal pump is commonly used in the fields of regional water diversion, agricultural irrigation, industrial cooling cycles and urban water supply and drainage [1]

  • Andmm/h h curves responding to n s are highly consistent with the measured q/ h − n/ h and m/h − n/ h curves in each quadrant, proving that the mathematical model derived in Section 2 to describe the q n m complete characteristic curves of the centrifugal

  • Considering that the traditional prediction method for the Complete pump characteristics (CPCs) is relatively low in terms of prediction accuracy and ignores the actual operation characteristics of the pump, a novel method considering the inherent operating characteristics of the centrifugal pump is proposed to predict the CPCs, which serves for the design of pump stations

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Summary

Introduction

Due to its wide range of flow and head, a centrifugal pump is commonly used in the fields of regional water diversion, agricultural irrigation, industrial cooling cycles and urban water supply and drainage [1]. Wu [22] built a prediction model of the normal performance curve of an axial flow pump based on an improved RBF neural network, and the prediction results were in good agreement with the experiments. With the rapid development of modern computer technology, CFD technology has gradually become an effective means to predict the CPCs. CFD technology is used to model the pump in three dimensions, set the operation conditions and calculate the flow field to obtain the simulation results, such as the pump inlet and outlet head, discharge, speed and torque under different operation conditions The mathematical transformation of these simulation results can realize the prediction of the CPCs. Höller [23] numerically simulated the steady-state and transient conditions of a mixed flow pump with CFD software, proposed a method to obtain the four quadrant characteristic curve of a mixed flow pump, and experimentally verified the accuracy of the method.

Materials and Methods
Suter Transformation
COPs Analysis
Characteristic Parameters of Points A and C
Characteristic Parameters of Points B and M
Characteristic Parameters of Points D and P
Model Verification
The characteristic parameters ofconstructed
Prediction Comparison
Case Study and Discussion
13. Simulation and valve two-stage closing conditions
Findings
Conclusions
Full Text
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