نوع مقاله : مقاله پژوهشی
1 عضو هیات علمی / دانشکده مهندسی مکانیک، دانشگاه تربیت دبیر شهید رجایی
2 دانشجوی کارشناسی ارشد / دانشکده مهندسی مکانیک، دانشگاه تربیت دبیر شهید رجایی
عنوان مقاله [English]
High pressure gas flow at the outlet of the nozzle jet and rocket engines and gas engines in the combustion chamber is one of the factors affecting driving force, fuel consumption, emissions and engine efficiency. Hence its study is very important. High pressure gas from the nozzle exit and the process of mixing with ambient air, depending on the flow properties of compressibility and density barrel shaped like waves, creating shock waves and the stopper. The purpose of this article is the numerical study of these properties. The Mach disk contours, speed and pressure profile that is the effective parameters in the gas flow exit from the nozzles are presented in this paper. Gas jet flow simulation results showed that high pressure ratio of 81.4:1, the formation of the gas jet boundary due to the high amount of kinetic energy is independent of viscosity or turbulent flow in the gas jet. Also the results showed that if the pressure ratio is higher than 18.6:1 the characteristics of the local Mach number and the dimensionless pressure P/Pn is independent of the pressure ratio between the nozzle and the environment, which it depends only on dimensionless distance x/d.