جستجوی مقالات مرتبط با کلیدواژه « سوزش فرسایشی » در نشریات گروه « مکانیک »

In this study, the simulation of internal ballistics and the exhaust flow of a solid propellant engine have been investigated. The flow field considered in this problem including the cylindrical grain and the solid wall of the engine and the flow at the nozzle outlet have been studied. The governing equations are used in an axisymmetric and compressible form to model the fuel combustion in non-erosive combustion mode. In the present study, cylindrical type of grain fuel is considered, which is one of the most useful types of fuel grains in terms of simplicity in production. In order to obtain the results from the simulation model which are close to the real data, used UDF modules in the Fluent software to describe some specific quantities and phenomena of the problem. Finally, the results obtained from the simulation in different modes of fuel burning are examined and show the accuracy of the numerical model by entering the parameters affecting the fuel burning.

In the present research, a new model is presented to predict the burning rate of a solid rocket motor (SRM) in the presence of erosive burning phenomenon. This model is based on the Wang model and the major modification is adding the pressure change in the erosive burning rate. In addition, the necessary relations needed to calculate the velocity gradient on the propellant surface in a one-dimensional internal ballistics code was presented. To assess the new model, the test results of a laboratory motor designed in this research were used. Also, to compare the performance and accuracy of this model with the other models, this motor was simulated with the presented model and the six available models. The results of the comparison indicate that the new model has better accuracy than the other models. The advantage of introducing the pressure effect in the Wang model has been shown. Another advantage of the new model is that this model doesn’t have any experimental constants dependent on the propellant composition or grain dimensions which is a common defect in popular models such as Lenoir-Robillard model.

The present survey focuses on experimental and numerical investigation of internal ballistic of Solid Fuel Rocket Engine (SFRE) for three different grains: bottom back-burning, annular side back-burning and all-side back-burning. To validate the developed numerical solution some experiments were performed and numerical results were compared to them. Accordingly the numerical results were compatible with that of experimental in an acceptable fashion which means the applied numerical method was appropriate to predict the behavior of SFRE. According to result, ignoring the transient effects, the combustion chamber pressure increased with increasing the area of burning region and vice versa. Also with increasing the combustion chamber pressure the effects of erosion burning declined. The more the combustion chamber pressure, the more the engine performance and the more the specific impulse were. Mostly the bottom back-burning grains provided constant-area burning region and consequently a constant pressure profile. Also area of burning region followed increasing and decreasing patterns for annular side back-burning and all-side back-burning respectively.

In this study, solid rocket motor internal ballistic, has been investigated. Flow field consists of internal grain space and converging-diverging nozzle. Axisymmetric, compressible and transient Euler equations have been considered as governing equations and erosive burning has been considered as an important phenomenon in solid rocket motors. Fluent software and its moving mesh capability have been used to flow field modeling. At the first time, an appropriate UDF has been utilized to achieve a good simulation of erosive burning. The results show very good agreement with other numerical results.