Расчётные исследования теплового состояния камеры сгорания двухкомпонентных жидкостных ракетных двигателей малой тяги, работающих при повышенных давлениях

Abstract

One of the main challenges facing the spacecraft designer is creating a propulsion system to control its movement with highly economical and reliable liquid rocket engine of small thrust (thrusters). The feed system for thrusters is predominantly pressurized gas-feed system (PGFS). However, the using of PGFS restricted area of low pressure feeding and low mass of propellants because the increasing the feed pressure or volume of propellants means increasing of dry weight of the tank. One of the possible ways to improve the mass-energy characteristics of thrusters and the orientation control system is to increase the pressure by using special composite tanks or using pneumatic-piston pump system. There are three thrusters for analysis: DMT-MAI-МАИ-200 (NTO-UDNH), С5-146.00-0 KB ChimMash (NTOUDNH), AMBR (NTO-Hydrazine). The calculation shows the advantage of using high pressure for small thrust rocket engine until 2MPa. The increase in the specific impulse is due to several factors: - increase in the theoretical thermodynamic specific impulse;- increase the reaction rate of recombination reduces losses during expansion; - reduction in friction losses in the boundary layer due to the decrease in the surface area of the combustion chamber; - improving the quality of atomization and increase the rate of evaporation due to increased exposure to heat; - decreasing of film cooling mass flow cause less length and surface area of the combustion chamber. The analysis show the changes the thermal state of combustion chambers wall, depending on the operating pressure, mixing parameters and film cooling mass flow. The advantage in weight characteristics of thrusters and orientation control system when using pressure up to 2 MPa.