جستجوی مقالات مرتبط با کلیدواژه "ramjet engine" در نشریات گروه "مکانیک"

In this research, the design of a can combustion chamber for a ramjet engine, the performance of this chamber and the role of flameholder have been studied. For this purpose, after talking about ramjet engine types, some general information about the combustion chamber has been explained. Then the process of chamber designing and determining its geometry has been discussed. The dimensions of the chamber were determined by using input conditions extracted from GasTurb software as well as applying a calculation code, and the geometry of the chamber have been determined by applying calculation codes. By evaluating the obtained geometry and ensuring the accuracy of the design, simulation of combustion with non-premixed liquid phase was carried out using Fluent software. While presenting the results, the effects of size, distance and number of flameholder have been investigated. It is shown that the use of flameholder in ramjet engines is essential but the use of large flameholder is not recommended.

In this research, the performance of ramjet engine combustion chamber has been evaluated by applying geometrical and physical changes such as changing the diameter of the chamber, changing the size and displacement of the secondary and dilution air holes and changing the mass flow passing through these holes. To do this, at first some typical ramjet combustion chambers were introduced and some of their features were discussed. Then using the information and guidance presented in scientific and technical references a suitable combustion chamber was designed for the defined inlet and outlet conditions. After the geometry has been determined, the simulation process has been carried out in Fluent software and while presenting the results, the performance of the chamber has been investigated. The results show that the values obtained for the geometry of the chamber and the position of the holes are reliable and changing the sizes has no global advantage and is not recommended. Furthermore, it is found that displacing air holes location could improve solution convergence.
 
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Inlet in ramjet engines are used to reduce the air flow from free stream to the required speed for flame stability in the combustion chamber. Hence the precise and correct design of inlet have rightly influence on whole system of ramjet engine performance. At the present work, an axisymmetric supersonic inlet with external compression has been designed based on requirements of the ramjet engine at Mach 2.1. Steady flow simulation was done for inlet individually by CFD software in different fuel flow and Mach numbers to investigate the inlet performance that integrated by other parts of engine. Then transient simulation performed for integrated engine by selection of a special fuel flow-time function that injected in combustor. The results of simulation exhibited the shock velocity and performance of inlet that integrated by the engine. The results show that the designed geometry can meet the desired performance requirements considering the fuel control system ability.