Thermodynamic Principles for the Gas Filling of Chambers in Aerospace Components during Pneumatic Vacuum Tests

New thermodynamic approaches to the filling of a chamber with control gas in pneumatic vacuum tests during the development of aerospace components are outlined. Two methods are developed for calculating gas compression in a chamber of constant volume with external heat transfer. A numerical experiment shows that they are effective. Successive approximation is used in calculating the external heat transfer. That method ensures the minimum error (<1%) in determining the pressure and temperature in the chamber.