Annotation: In the present-day rocket engineering, the liquid rocket engines with pump feed system have gained wide acceptance. As a rule, the pumps used in liquid rocket engines are screw-axifugal. The screw serves to increase pressure upstream of the axifugal wheel, thus ensuring its cavitation-free operation. The screws used in the screw-axifugal pumps of liquid rocket engines may be of two types: with constant and variable step. The screws with constant step are easier to calculate, profile and manufacture as compared to the screws with variable step. As known from the literature, the use of the screw with variable step increases power characteristics of the screw-axifugal pump. The purpose of investigation is comparative analysis of cavitation and power characteristics of the following high-speed low-consumption screw-axifugal pumps of liquid rocket engines with jointed screws, screws of constant and variable step:  RD868 engine oxidizer and fuel pumps;  RD859 engine fuel pumps;  RD861K engine fuel pumps. Besides, the analysis has been made of the impact of design features and geometrical dimensions of the screws with variable and constant step on power characteristics of the screw-axifugal high-speed lowconsumption pumps of liquid rocket engines. Special attention has been given to the analysis of anticavitation properties of the pumps with screws of variable step and pumps with jointed screws. Based on the results of investigation, it has been ascertained that when using the joint screws and screws with variable step instead of the screws with constant step in the high-speed low-consumption screw-axifugal pumps of liquid rocket engines, the pump delivery head increases from 0.65 to 3.83%, the efficiency increases up to 1.7%. The use of jointed screw and screw of variable step as compared with the screw of constant step does not have any impact on cavitation properties of low-consumption crew-axifugal pumps of liquid rocket engines.

Annotation: Two design options of manifold and dividing valve are considered, the loss calculation by analytical and numerical methods has been made. Based on the calculation results, the optimal design option has been selected. The calculation correctness is confirmed as a result of development tests of the design.

Annotation: To support ignition of Taurus LV first stage core structure engine, an oxidizer dividing valve has been developed that ensures minimal hydraulic resistance, opening time and hydraulic impact. The paper considers the valve design, main phases of its ground development testing and basic critical comments on the design made in the process of manufacturing and testing.

Annotation: The calculation procedure is proposed, the analysis is made and the ranges of optimal probability values of no-failure operation of pneumohydraulic propellant supply system and its elements are determined based on general requirements to integrated launch vehicle.

Annotation: One of the main design parameters of the automatic equipment in the launch vehicle’s pneumohydraulic systems is the flow friction characteristic, which represents the proportionality factor between the automatic equipment pressure differential and velocity head. The flow friction characteristic of the completely open automatic device should have very small value with required dimensions and mass. With decrease of the pressure losses, the required upstream pressure of the propulsion system is ensured with smaller pressurization of the tanks. It results in the decrease of the required pressurization gas volume, which boosts reduction of the performance of the launch vehicle as a whole. This paper describes the method of reduction of the flow friction characteristic of the dividing valve, optimizing the geometric shape of the flow passage. The problem of minimization of the valve’s flow friction characteristic is considered with the specified mass and design dimensions restrictions. The initial design of the valve was developed, taking into account the specified requirements, literature references and parameters of the analogue units. With the goal of optimization various options of valve design were considered, different from the initial design in configuration of the inlet and discharge nozzles, notably various angle sizes, forming the stream profile, and lengths of the direct-flow sections. Four options of the valve design were calculated using numerical methods of ANSYS CFX software. Navier – Stokes equations and k-ω SST turbulence model were used. Based on the calculations results the optimal design was selected. Initial design of the valve was compared with the optimal one. The flow friction characteristic of the optimal valve design decreased by 26 % in comparison with initial design with insignificant change of mass and dimensions. The design of the developed dividing valve can be involved in the design of the new launch vehicles.

Annotation: The general information on gas pressure reducers, on their purpose in launch vehicles and spacecraft pneumohydraulic systems is set forth. The impact of different operating conditions on physical characteristics of these devices is considered. The main and auxiliary parametric characteristics of the reducer are presented and the physical process of gas pressure reduction in it is explained. The error of output pressure regulation is evaluated using full differential of function, whose arguments (input pressure, flow rate, temperature) have scatter. The reducer temperature curve is shown and the impact of structural temperature on the value of dynamic (with flow rate) and static (without flow rate) pressure in reducer output cavity is explained. The difference between the excess pressure reducer and absolute pressure reducer is shown. The brief review of the designs of liquid and bimetal thermal compensators is presented, their advantages and disadvantages are described and the experience of reducers testing with regulating springs made of elinvar is analyzed. Attention is focused on operating temperature and its impact on stability of reducer adjustment. The formulas that describe thermodynamic processes occurring in the reducer are presented. Special attention is given to the properties of regulating spring of the reducer because of change of elasticity modulus coefficient at different temperatures, the expected pressure scatter at reducer output is evaluated and the necessity of measures to reduce this error is explained. To compensate for temperature disturbance, the formula of gas pressure in closed volume of sensitive element is derived. The essence of original technique of pneumocorrection of initial pressure in sensitive element cavity that was proposed and introduced on Yuzhnoye SDO-developed reducers is set forth.