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: 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.