جستجوی مقالات مرتبط با کلیدواژه « رم جت » در نشریات گروه « مکانیک »

In present research the combustion process of solid fuel ramjet(SFRJ) was modeled in numerical state. Different five geometrical cases were employed for parametric study of back step height and aft-combustor length effects on propulsion properties in this numerical model. Results showed less than 10 percentage error in compare with reference data. Extracted numerical data from this research show decreasing burning rate, increasing combustion efficiency and thrust force due to increasing the step height also decreasing combustion efficiency and thrust force as results of decreasing the aft-combustor length. The results demonstrate that variation of the aft-combustor length hasn’t sensible effect on burning rate also optimum value for specific impulse occur when dimensionless aft-combustor length is equal to 0.95.

The second law of thermodynamics and exergy is an important issue in the analysis of propulsion systems that have been highly regarded by researchers in recent years. Studies show that the analysis of the first law in air propulsion systems alone has low scientific value, and for a complete study of a system, the second law and exergy should also be considered. Thermodynamic analysis of supersonic air engines, especially Ramjet and Scramjet engines, with the aim of studying their performance, has attracted the attention of many researchers in the last decade. In this method, using thermodynamic laws and exergy analyzes, Ramjet and Scramjet motors are systematically analyzed, and their optimal state is extracted. The main purpose of this study is to review and present the latest research findings in this field, focusing on Ramjet and Scramjet engines.

Ultra sonic Ram-Jet and Scram-Jet are high technology engines in aerospace industries. Scram-Jet engine can achieve higher velocity than common Ram-Jet, because its combustion is done in ultrasonic velocity. Combustion in ultrasonic velocity needs stability. Since cavities are very important in combustion stability of ultrasonic reaction flows, in this paper different parameters effects of ultrasonic cavity flow wall shear layer was solved using different turbulence modeling and studied with numerical simulation. Firstly, the best turbulence model in solution precision and speed introduced for wall shear layer solution in ultrasonic cavity flow. Then after model selection, solution continued for different cavity wall angle and its results compared. The results shown that SST-k-ω turbulence model is the best model in precision and speed for ultrasonic cavity flow wall shear layer solution, also the results of different angles for back normal wall in this research shown that in cavity with steep angle temperature increase sharply, thus the temperature is very important parameter in indicating angle value and the limitation of the melting point used may affect the angle selection.