American Scientific Journal № (32) / 2019 13 ТЕХНИЧЕСКИЕ НАУКИ THE THERMO-GAS-DYNAMIC DESIGN METHOD FOR THE LIQUID ROCKET ENGINE CHAMBER Pashayev Arif Mir Jalal, Doctor of Physical and Mathematical Sciences, Academician of ANAS, National Aviation Academy Samadov Adalat Soltan, Prof., Flight Vehicles and Engines Department Abdullayev Parviz Shahmurad, Prof., Head of Flight Vehicles and Engines Department Abdulla Nijat Parviz, MSc student, Department of Design Rocket-Space Apparatuses, NAU “KhAI” Abstract. Analysis of the thermodynamic and thermophysical properties of combustion products in the liquid rocket engine (LRE) chamber shows that their dissociation degree depends on temperature T, gas expansion degree ε, etc. Practically, combustion products are always chemically active working fluid, therefore the number of moles N of the products varies along the length of the LRE chamber in the entire reaction mixture. The local values of the parameters T and N depend on the specific physical conditions. Therefore, the distribution of local numbers of moles of the components of the gas mixture and its heat capacities can be represented as dependencies N~f(T) and c~g(T). For this purpose on the basis of the numerical values of the moles and the heat capacities of the gas mixture components in the main sections of the LRE chamber are formed as corresponding empirical functions through interpolation. The system of equations for the thermodynamic calculation of LRE chamber is solved by taking into account new functions. Such approach allows forming the optimal contour of the LRE chamber at the preliminary stage of engine design and improving results of the gas-dynamic calculation and nozzle profiling by modified method of characteristics. INTRODUCTION As known, one of the main directions in rocket and space technologies development is design of highly efficient propulsion systems, which include liquid rocket engines (LRE). Design of LRE and its optimization scheme consists of choosing a combination of parameters of the workflow, which achieves the most advantageous combination of traction characteristics and weight of the structure. There accumulated a large scientific and practical experience in the development of various LRE. However, determining the design parameters of a new designed LRE camera is still a difficult process. In LRE development their initial geometry, pneumatic-hydraulic scheme (PHS) of the engine and parameters of these energy relations are determined. Next, on the basis of this PHS is selected, at all characteristic point of PHS pressures, consumption of fuel components, required pump features and power consumed by them and components temperatures of working gases are determined. These engine parameters obtained are the initial data for the design of the LRE combustion chamber (CC), gas generator, pumps, turbines, regulators, etc. The pressure and the ratio of fuel components in the CC is selected taking into account obtaining a maximum specific impulse of the engine, its dimensions and reliable cooling of the chamber. At this design stage many parameters of LRE and its aggregates are taken approximately based on the experience of previous developments. Therefore, great accuracy in determining of certain engine parameters at characteristic points of PHS and LRE chamber should not be expected. For determination of the thermodynamic characteristics of combustion products (CP) have been done many researches and developed a number of different software (for example, CEA (NASA, USA), Astra.4/pc (MSTU named after N.E.Bauman, Russia), RPA (Alexander Ponomarenko, Germany), etc. In these applications is assumed that (for CC exit, the nozzle inlet): • fuel mixing is complete, • physical incomplete combustion missing, • the combustion process takes place at a constant pressure in the CC ( const p c = ), • combustion products systems at the CC exit are in a thermodynamic equilibrium state, • there is no heat exchange with CC walls, • gas phase is described by the ideal gas state equation, • solubility of gases in the liquid and solid phases is missing, • condensed substances form one-component immiscible phases, etc. For the expansion process calculating in the nozzle, the following assumptions are made: • the expansion process is chemically and energetically extremely balanced, • no fuel burnout in the nozzle, • no heat transfer to the nozzle walls, • there is no friction and gas-dynamic losses in the nozzle [Alemasov,1989; Babkin, 1990;