Influence of the Tip Clearance on the Energy Loss of the Multiphase Pump Based on the Entropy Generation Theory

The existence of tip clearance makes the energy loss of the multiphase pump large. Therefore, in order to study the influence of tip clearance on the energy loss, the method based on entropy generation theory is used to analyze the energy loss in the multiphase pump under the different tip clearances. It is found that the turbulent dissipation rate in the impeller is greater than that in the guide vane, and the maximum value of the turbulent dissipation rate occurs in the middle of the impeller. The increase of tip clearance has a significant effect on the control of turbulent dissipation at the outlet of guide vane. The increase of tip clearance will lead to the increase of entropy generation and energy loss in the middle region of the impeller, and the maximum value of entropy generation will gradually move backward. The distribution of the high entropy generation on the impeller wall is mainly located near the pressure surface of the blade, the tip clearance, the leading edge of the blade inlet and the inlet hub. The size of the tip clearance is not the only index to measure the clearance loss of the blade tip, and the loss is not linearly related to the size, but is jointly determined by other operating conditions.