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| Numerical simulation of stress and mode of rotor system of high-temperature molten-salt pump |
| WANG Zichao,ZHANG Desheng*,JIN Yongxin,GAO Xiongfa,DONG Yaguang |
| National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China |
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Abstract In order to improve the operational reliability of high-temperature multi-stage molten salt pumpof the solar thermal power system, the structural stress of molten salt pump at extreme high temperature condition is analyzed systematically based on the fluid-solid-thermal multi-field coupling theory. The model characteristics of high-temperature rotor system under the action of without and with prestressed, which contains fluid pressure, inertial force and temperature load, are compared and analyzed respectively. The results show that the density and viscosity of molten salt medium have little effect on the external characteristics, and the water test results can be used as a reference for the ope-ration performance of high temperature molten salt. The temperature of the impellers rises with the increase of the impeller stages. The temperature change of the impeller is distributed symmetrically in the center. The maximum temperature of the impeller increases as the flow rate decreases. The main stress on the impeller comes from the fluid pressure and inertial force load, as well as the distribution is symmetrical. There is stress concentration at the intersection area of front and rear cover plate and blade. The stress at the trailing edge of the blade rises significantly to over 60.000 MPa. Temperature is the main factor of impeller deformation. Impeller deformation increases with temperature rise. The natural frequency of the rotor structure with prestressing is higher than that without prestressing, whose magnitude of the rise is 109%-498%, and the amplitude change of each step is not obvious. The critical speed of the molten salt pump deviates from the rated speed of the pump, which avoids the resonance of the rotor system during operation. The research results can provide a theoretical basis for the design and development of high temperature molten salt pump.
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Received: 03 March 2021
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