Space systems design (spacecraft, satellites, space stations and their equipment)
Sajjad Gharezi; Mohammad Mehdi Doustdar
Articles in Press, Accepted Manuscript, Available Online from 17 January 2024
Abstract
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 ...
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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.
Mohammad Moumivand; hasan mohammadkhani; javad heydari; mohammad hosein vaezi
Volume 10, Issue 2 , September 2017, , Pages 65-72
Abstract
Determining aerodynamic coefficients and control and stability derivatives play animportant role in the development of flight vehicles. In this paper, roll damping coefficientof BASIC FINNER standard model is determined at different attack angles and withvarious Mach numbers using numerical Sliding Mesh ...
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Determining aerodynamic coefficients and control and stability derivatives play animportant role in the development of flight vehicles. In this paper, roll damping coefficientof BASIC FINNER standard model is determined at different attack angles and withvarious Mach numbers using numerical Sliding Mesh method. Also, the impact of theeffective parameters such as amplitude and frequency of oscillation, time step and numberof iteration in each step in numerical solution are investigated to determine the rolldamping coefficients. Geometry modeling and grid generation and the flow analysis aredone by ANSYS CFX and ANSYS FLUENT software, respectively. In this simulation,Euler’s flow equations, compressible and unsteady flow, finite volume method and densitybased solver with explicit formulation and first-order accuracy for a numerical solutionare used. To evaluate the results of a numerical study, a comparison is made between theexperimental data and MD results, indicating that the results have a good accuracy.
M.M. Gheisari; S. M. Mirsajedi
Volume 7, Issue 3 , October 2014, , Pages 23-32
Abstract
In this research, second order level set method for simulation of grain burn-back analysis is presented and compared with the first order level set according to discretisation technique, accuracy , and CPU time. In this manner and at the first step, we describe total necessities of level set method that ...
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In this research, second order level set method for simulation of grain burn-back analysis is presented and compared with the first order level set according to discretisation technique, accuracy , and CPU time. In this manner and at the first step, we describe total necessities of level set method that are grid generation, minimum distance function calculation, relative condition estimation, ballistic characteristics calculation, and obtaining results. Then, at the second step, we improve forth necessity of level set method by second order model. For validation of presented model, we consider many type of simple and complex grains and evaluate grain burn-back analysis. The obtained results indicate that second order model is more accurate than the first order model for simulation of complex grains. But, at the simple grains with more CPU time related to second order model, accuracy of two models are similar. A compromise between accuracy and CPU time suggest that one can use second order model for simulation of complex grains and first order model for simulation of simple grains.
