Mathematical Models of Low-Temperature Gas Generator

The low-temperature gas generator (LTGG) is designed to produce gas with a temperature of 350–450 K. The LTTG consists of the combustion chamber with solid propellent and a cooling chamber with granules of a solid refrigerant. Combustion products have a high temperature, which does not make it possible to use them in a whole number of technical devices. Gas cools down while interacting with solid refrigerant granules, which takes part of the gas internal energy to decompose. In order to describe heat and mass transfer processes in an LTGG, we developed a mathematical thermodynamic and one-dimensional models based on one-dimensional equations of continuity, momentum, energy, and the integrity of gas-mixture components. The gas mixture consists of combustion products, refrigerant decomposition products, and air. The mathematical model takes into account the gas-mixture flow in an LTGG, heat exchange with the structural elements of an LTGG, and kinetics of the refrigerant granule decomposition. To activate the mathematical model, a numerical method has been developed for solving boundary-level problems based on the method of finite differences. The system of equations is approximated by means of implicit differences schemes. Solving nonlinear differential equations involves the Newton’s method. The boundary-value problem was solved through an orthogonal factorization.