Effect of rotational speed of spiral shell on liquid flow characteristics in cavity
LIU Zailun1,2, GU Shengfu1*, ZHAO Weiguo1,2, LYU Peitao1, ZENG Jilai1
1. College of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 2. Key Laboratory of Fluid Machinery and Systems, Gansu Province, Lanzhou, Gansu 730050, China
Abstract:In order to study the influence of the rotational, speed of the spiral shell on the liquid flow characteristics in the cavity, the experimental roto-jet pump was used as the research object. On the basis of verifying the accuracy of the synchronous rotation experiment and simulation results of the impeller and the spiral shell, the RNG k-ε turbulence model was used for numerical calculation for five models with the same impeller speed and different spiral shell speeds to analyze the change of the fluid flow characteristics in the cavity and study the performance of the pump. The results show that as the rotational speed of the spiral shell increases, both the peripheral velocity and the rotation coefficient of the liquid increase, the peripheral velocity curve gradually forms concentric circles along the radial direction, and the liquid in the cavity rotates non-rigidly. The radial pressure gradient of the fluid in the cavity increases when the pressure is lower than 624 kPa, whereby a higher rotational, speed results in a lower pressure. When the pressure is higher than 624 kPa, a higher rotational speed results in a higher pressure. The vortices in the upstream region of the collector are distributed near the inlet, and the vortices in the wake region are concentrated at the end of the diffuser section, resulting in an overall increasing trend. As the speed of the spiral shell increases, the head of the pump increases, but the efficiency decreases. By changing the diameter of the inlet of the collecting pipe, it is found that the collecting pipe is not the main reason for the decrease in efficiency, but the increase of the friction loss of the disc causes the decrease. The loss increases with the increase of the rotational speed of the spiral shell in a 3rd power function, and the optimal inlet diameter that is used in this paper is 13 mm.
刘在伦,顾生富*,赵伟国,吕佩涛,曾继来. 旋壳转速对腔内液体流动特性的效应[J]. 排灌机械工程学报, 2023, 41(2): 124-132.
LIU Zailun,GU Shengfu*,ZHAO Weiguo,LYU Peitao,ZENG Jilai. Effect of rotational speed of spiral shell on liquid flow characteristics in cavity. Journal of Drainage and Irrigation Machinery Engin, 2023, 41(2): 124-132.