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| Influence of blade shape of liquid-ring pump on inlet reverse flow and its hydraulic characteristics |
| ZHANG Renhui1, 2*, ZHANG Jingxian1, GUO Guangqiang1 |
| 1. College of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 2. Key Laboratory of Fluid Machinery and Systems, Lanzhou University of Technology, Lanzhou, Gansu 730050, China |
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Abstract To reduce the flow impact and suppress the reverse flow at the blade inlet of the liquid-ring pump, the transient gas-liquid two-phase flow was simulated using numerical methods. The effects of blade shape on the inlet reverse flow and its hydraulic performance of the liquid-ring pump were analyzed in terms of the blade profile and the distortion of the blade inlet. The research results indicate that the inlet twisted blade of a liquid-ring pump can effectively suppress the flow separation caused by inlet flow impact. However, the inlet twisted blade causes the backward movement of the vane channel, which results in the decrease of the first channel volume expansion for the movement of the gas-liquid interface, and the reverse flow of the blade inlet aggravates. Due to the circumferential asymmetry of the flow channel, the vacuum generated at the inlet of each channel in the suction area is different. By introducing the relative volume expansion rate caused by the movement of the gas-liquid interface, the pressure distribution of the impeller inlet and reverse flow structure can be properly explained. Based on the inlet distorted blade design, the non-suction side forward bending can effectively improve the relative volume expansion rate of the flow channel at the beginning of the suction port. For the non-suction side forward bending design of the 6° inlet distorted blade liquid-ring pump, the reverse flow near the inlet is further suppressed, and the pump efficiency is increased from 15.46% to 16.20%. The influence of the blade wrap angle on the inlet vacuum and inlet reverse flow strength is significantly greater than that of the blade outlet angle. With the increase of the blade wrap angle, the vane channel at the beginning of the suction port move forward along the rotation direction of the impeller, which causes the increase of the volume expansion rate in this channel. Then, the reverse flow near the impeller inlet is suppressed, as a result, the vacuum and efficiency of the liquid-ring pump are improved.
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Received: 11 March 2022
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