In order to explore the influence of rotating speed on the internal flow and sealing characteristics of the liquid-sealing impeller for a liquid oxygen turbopump of a rocket engine, unsteady numerical simulations of the flow characteristics and sealing performance of the first-stage liquid-sealing impeller for a liquid oxygen turbopump under liquid phase conditions were performed. The results show that the pressurization value increases with the increase in the rotating speed. The first-stage liquid-sealing impeller, whose structure is symmetrically distributed along the center of the rotation axis, tends to be an isobaric seal at a rotating speed of 12,000 rpm, and when the rotating speed is decreased or increased, it enters the leakage state or negative pressure sealing state, respectively. The matching relationship between the rotating speed and inlet pressure has a significant effect on the pressurization value, pressurization coefficient and leakage flow rate. Under the working condition with a good match between the rotating speed and inlet pressure, the pressurization value increases significantly and the leakage flow rate decreases significantly, and the pressurization coefficient is stable between 0.88 and 0.89. The empirical formulas proposed by Wood and the Shanghai Research Institute of Chemical Industry (1979) have high reference values for the design of the liquid-sealing impeller with a flow channel (groove) and retainer.

Based on the discrete phase model (DPM), solid–liquid two-phase flow calculation, particle settling theory and MATLAB image processing technology, the influence of the installation position of submersible pumps on the deposition characteristics in a cylinder-type prefabricated pumping station was studied, and two performance indices, the deposition rate and area ratio of the easy deposition region were proposed. The results show that the area ratio and deposition rate of the easy deposition region increase as the suspension height increases. The discharge effect is best when the suspension height is 0.1H0, however, at this time the inlet bias of the pump is larger, which is not conducive to the smooth operation of submersible pumps. The area ratio and deposition rate of the easy deposition region gradually increase with the increase in the interval of the pumps. As the center distance increases, the area ratio and deposition rate of the easy deposition region basically decreases first and then increases, and reach the minimum at 0.1R and 0R, respectively.

This study investigated the sealing performance of the multistage liquid-sealing impellers of a turbopump. To achieve this purpose, the influence of each structural parameter in the impeller on the pressurization coefficient φ2 and the leakage flow rate Q was analyzed based on response surface methodology, taking the maximum pressurization coefficient φ2 and the minimum leakage flow rate Q as the optimization objectives. We obtained satisfactory ranges for parameters φ2 and Q. A set of parameter combinations was selected as the optimization scheme using the Box–Behnken method for the optimal solution design. The numerical simulation results show that to keep φ2 and Q in the better range, the value ranges of groove width b, groove depth h and groove number z should be (12.8–14 mm), (4.5–5.6 mm) and (23.5–28), respectively. Compared with the original model, the optimized version has an average increase of about 2.5% in pressurization coefficient φ2 at each rotation speed, an average of about 8.2% reduction in the leakage flow rate Q in the leakage state and an average increase in the reverse flow rate Q by about 6.7% in the negative pressure sealing state, indicating better sealing. By comparing pressure data at the experimental monitoring points, the proposed method was verified to have a high degree of confidence.