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| Effect of inducer inlet hub ratio on suction performance of a centrifugal pump |
| CHENG Xiaorui1,2*, TU Yixuan1, TENG Fei1, LIU He1 |
| 1. College of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 2. Key Laboratory of Fluid Machinery and System, Gansu Province, Lanzhou, Gansu 730050, China |
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Abstract Based on numerical simulation and experiment, the influence of inducer inlet hub ratio on suction performance was investigated in terms of a type of submersible electric cryogenic LNG pump. Three-dimensional, steady, turbulent, cavitating flows in the pump were simulated by using the RNG k-ε turbulence model along with the full cavitation model, and the accuracy of simulations was validated with experiment on a model pump. Five pumps were designed with five inlet hub ratios such as 0.260, 0.274, 0.289, 0.303 and 0.318, respectively. The cavitation developing process, static pressure distribution in the inducer and impeller and suction performances curve of these pumps were analyzed and compared. The results showed that the cavitation developing processes in the inducer and impeller are basically identical, i.e. a cavity always occurs firstly in the low-pressure zone at the inducer inlet tip regardless of inlet hub ratio. An increasing inducer inlet hub ratio can result in an increased meridian velocity at the inlet, and reduce the angle of attack. As a result, flow separation occurs on the blade suction side, and the low-pressure zone expands gradually; eventually the pump suction perfor-mance is impaired. Therefore, in order to obtain a better suction performance, the inducer inlet hub ratio can be reduced in a proper range.
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Received: 13 April 2019
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