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| Influence of medium viscosity on pressure pulsation characteristics of pump as hydraulic turbine with guide vane |
| BI Zhigao1,2*, CAO Baowei1,2, WANG Jinxi1,2, WANG Zhanhui1,2, GAO Yong1,2, MA Yajun2 |
| 1. School of Chemistry and Chemical Engineering, Yulin University, Yulin, Shaanxi 719000, China; 2. Key Laboratory of Low Metamorphic Coal Clean Utilization, Shaanxi Province, Yulin, Shaanxi 719000, China |
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Abstract In order to explore the influence of medium viscosity on the pressure pulsation characteri-stics of hydraulic turbine, based on the Reynolds time averaged N-S equation and standard k-ε turbulence model, some centrifugal pump with guide vane reversed as turbine(PAT)was chosen as the research object, water and two kinds of viscous oil were taken as the contrast medium, three-dimensional transient numerical simulation was carried out, and then the simulation results were analyzed in the time domain and frequency domain. The results show that there are unsteady vortexes with the same direction of rotation as the blade in partial impeller passages under clean water, while the flow field structure of the impeller and draft pipe under viscous oil is significantly improved. Under viscous action, coherent interaction of dynamic and static cascades is still the main inducement for pressure pulsation in the PAT. The mean pressure pulsation in the guide vane is the most intense, followed by the impeller, and the draft pipe is the least, and this law is not affected by the viscosity. With the me-dium viscosity increasing, the peak-peak value and the dimensionless maximum pressure pulsation amplitude at each monitoring point decrease, which synchronize with the basic frequency amplitude and the secondary basic frequency amplitude at monitoring points in the guide vane and the draft pipe, however, which are quite different from those at monitoring points in the volute and impeller, while they synchronize with the sum amplitude of them. At the same time, the greater the viscosity, the lower the mean static pressure of each measuring point in the volute, guide vane and impeller.
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Received: 05 July 2021
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