TO DETERMINATION THE FLOW PARAMETERS AT THE OUTLET OF THE COOLING CURTAIN OF THE LIQUID-PROPELLANT ROCKET ENGINE COMBUSTION CHAMBER

The design of liquid propellant rocket engines (LPREs) necessitates the efficient cooling of the combustion chamber walls. Despite the prevalence of regenerative cooling, it frequently proves inadequate, necessitating supplementary techniques such as the injection of coolant into the combustion chamber to establish a thermal barrier. A critical deficiency in the prevailing methodologies pertains to the absence of dependable methodologies for the calculation of the parameters governing coolant flow as it transitions from the cooling path to the curtain belt. The objective of this study is to derive analytical formulas for determining the parameters of the coolant flow at the exit from the curtain belt of the cooling belt of an LPR combustion chamber. The coolant passes through tangential cylindrical channels into the annular slot, thereby forming a continuous swirling flow prior to entering the chamber. The analysis is conducted in two stages. First, a one-dimensional approximation is used to determine the temperature change in the cylindrical inlet channel. Then, the flow in the annular slot is considered using the laws of conservation of mass, momentum and energy. An analytical solution for the temperature distribution is obtained by means of simplification of the dependence for the Nusselt number. The model has been verified on the data of the RD-108 engine curtain belt with kerosene as a coolant. The results indicate that the coolant temperature at the outlet is nearly equal to the temperature of the chamber wall, thereby substantiating the practical applicability of the model. In this paper, analytical expressions for the coolant flow parameters at the outlet of the curtain belt are obtained for the first time, and an approximate method for evaluating the heat transfer in the annular slot is proposed. Despite its inability to account for alterations in fluid properties and variable wall temperature, the model functions as a framework for subsequent refinements.