Numerical Calculation of Energy Performance and Transient Characteristics of Centrifugal Pump under Gas-Liquid Two-Phase Condition

Abstract

The unstable operation of a centrifugal pump under the gas-liquid two-phase condition seriously affects its performance and reliability. In order to study the gas phase distribution and the unsteady force in an impeller, based on the Euler-Euler heterogeneous flow model, the steady and unsteady numerical calculations of the gas-liquid two-phase full flow field in a centrifugal pump was carried out, and the simulation results were compared with the test data. The results show that the test results are in good agreement with the simulation data, which proves the accuracy of the numerical calculation method. The energy performance curve of the model pump decreases with the increase of the gas content, which illustrates a serious impact on the performance under the part-load operating condition. The results reveal that the high-efficiency-operating range become narrow, as the gas content increases. The gas phase is mainly distributed on the suction surface of the impeller blades. When the gas content reaches a certain value, the gas phase separation occurs. As the inlet gas content increases, the radial force on the impeller blades decreases. The pattern of the pressure pulsation is similar to that under pure water and low gas content conditions, and the number of peaks during the pulsation is equal to the number of the impeller blades. After the gas content reaches a certain value, the pressure fluctuates disorderly and the magnitude and the direction of radial force change frequently, which are detrimental to the operation stability of the pump. The intensity of the pressure pulsations in the impeller flow channel continues to increase in the direction of the flow under pure water conditions. The pressure pulsation intensities at the blade inlet and the volute tongue become more severe with the increase of the gas content.

Study on the Unsteady Characteristics and Radial Force of a Single-Channel Centrifugal Pump

“…To analyze the effect of radial force on the pump impeller, eq was employed, which was derived from Zhou et al F = F x 2 + F y 2 …”

“…To analyze the effect of radial force on the pump impeller, eq 11 was employed, which was derived from Zhou et al 25 Figure 16 presents a diagram of the frequency domain distribution of the radial force. The frequency components of the radial force on the single-channel centrifugal pump are mainly the impeller frequency and its harmonics.…”

State of the Art on Two-Phase Non-Miscible Liquid/Gas Flow Transport Analysis in Radial Centrifugal Pumps Part C: CFD Approaches with Emphasis on Improved Models

“…Si et al [40][41][42] and Wang et al [53] presented validated numerical results of a 3D-bladed centrifugal pump in two-phase air-water flow and compared different impeller designs. Zhou et al [54] investigated transient, i.e., time-resolved, characteristics of the radial pump force, and Zhong et al [55] analyzed the transient pump characteristics that start when air is injected in the suction pipe. The EE2F model was also adopted in our previous studies, comparing a closed and a semi-open impeller [56][57][58].…”

Gas–Liquid Two-Phase Flow Pattern Identification of a Centrifugal Pump Based on SMOTE and Artificial Neural Network

“…In practical engineering applications, gas-liquid two-phase flow is frequently encountered, reducing the performance of the pump [2,3]. The increase of inlet gas volume not only affects the pressure increment and efficiency of a centrifugal pump, but also produces surging and even gas locking of the pump, which will endanger the stability of flow system and reduce the service life of the pump [4,5]. Therefore, the prediction of pump performance under the gas-liquid two-phase flow condition is of great significance.…”