%0 Journal Article %T NEW QUASI-STATIONARY THERMODYNAMIC APPROACH IN THE INTERNAL BALLISTICS AND THE INTERNAL COMBUSTION ENGINES %A Marian Nikolov Mutafchiev %J MEST Journal %P 90-98 %@ 2334-7058 %D 2015 %R 10.12709/mest.03.03.02.10 %X A new principal equation of the internal ballistics is presented herein, which is determining the temperature in the barreled firing weapons and the rocket engines with solid fuel during combustion of the charge. By this new equation it is demonstrated, that during ˇ°internal combustionˇ± in the thermodynamic system is not enthalpy imported, but internal energy. On that basis equations, determining the temperature and pressure in the cylindrical space of a piston-type internal combustion engines during the working process, are developed. Equations, determining the average temperature in the chambers of the vane gas turbine engines are also developed. Equation, determining the temperature in the combustion chambers of rocket engines with liquid fuel is also developed. Equations for determining the pressure and temperature in the gas engine of automatic firing weapons as well as collectors of piston engines are also presented. %K Internal ballistics %K internal combustion engines %K rocket engines with liquid fuel %U http://mest.meste.org/MEST_2_2015/6_10.pdf