Thermodynamic principles of calculation of the process of filling of cavities of rocket and space technology products with gas during pneumatic vacuum tests

New thermodynamic approaches to solution of the problem of filling of the test volume with a control gas during pneumatic vacuum tests in the process of development of rocket and space equipment are presented. Two methods for calculation of the process of gas compression in a constant volume cavity with external heat exchange are developed. Their effectiveness is shown by a numerical experiment. Successive approximation is used in calculation of external heat exchange. The method based on successive approximation in calculation of external heat exchange ensures minimal (less than 1 %) error in determination of pressure and temperature in the test cavity. Keywords pneumatic vacuum tests, constant volume cavity, compression, calculation, polytropic index, pressure, temperature, mass [email protected]