Aerospace Science and Technology
Omid Habibi; Reza Ebrahimi; Hassan Karimi Mazraeh Shahi
Volume 14, Issue 2 , October 2021, , Pages 141-151
Abstract
The nozzle, an end-element of the propulsive process Cycle, represents a critical part of any aerospace vehicle. The task of accelerating and efficiently exhausting combusted and reactive gases according to the delivered thrust represents the main objective of the propulsion system design. Flow separation ...
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The nozzle, an end-element of the propulsive process Cycle, represents a critical part of any aerospace vehicle. The task of accelerating and efficiently exhausting combusted and reactive gases according to the delivered thrust represents the main objective of the propulsion system design. Flow separation in supersonic convergent–divergent nozzles has been the subject of several experimental and numerical studies in the past. Now, with the renewed interest in supersonic flights and space vehicles, the subject has become increasingly important, especially for aerospace applications (rockets, missiles, supersonic aircrafts, etc). Flow separation in supersonic nozzles is a basic fluid dynamics phenomenon that occurs at a certain pressure ratio of chamber to ambient pressure, resulting in shock formation and shock/turbulent-boundary layer interaction inside the nozzle. From purely gas-dynamics point of view, this problem involves basic structure of shock interactions with separation shock, which consists of incident shock, Mach reflections, reflected shock, triple point and slip lines. In this article A Review on Flow Separation Phenomenon for Supersonic Convergent–Divergent Nozzles has been investigated.
Aerospace Science and Technology
Mahyar Naderi; Liang Guozhu; Hassan Karimi; Sara Pourdaraei
Abstract
In order to reduce cost and time along with enhancing the safety issues, numerical computer modelling and simulations are widely used for analyzing complex systems such as launch vehicle or spacecraft propulsion system. The objective of this research is to obtain an algorithm for simulation of ...
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In order to reduce cost and time along with enhancing the safety issues, numerical computer modelling and simulations are widely used for analyzing complex systems such as launch vehicle or spacecraft propulsion system. The objective of this research is to obtain an algorithm for simulation of staged combustion cycle liquid propellant engines. For this purpose the space shuttle main engine (SSME), as one of the world’s most complicated engines, is selected as a case study. A total of 34 elements is taken into account and using more than 100 linear/non-linear equations, the engine’s steady state system model has been established in MATLAB SIMULINK software. The simulation method uses eleven nested loops for iteration. The algorithm is based on the known parameters at the inlet of engine main feed lines namely mass flow rate and pressure, similar to the known conditions during hot test of engine on test stand. The simulation is capable of predicting the engine’s operation in wide range of thrust throttling levels from 69 percent to 109 percent of the nominal thrust. In order to validate the suggested method, SSME main component parameters, operating at 109 percent of rated thrust is presented. Simulation result mean error is less than 5 percent.
Hassan Karimi; Amir Nassirharand
Volume 3, Issue 1 , March 2006, , Pages 23-30
Abstract
In this paper application of a simulation algorithm for dynamic and nonlinear analysis of a specific liquid propellant engine is presented. The mathematical model of the engine includes a set of nonlinear algebraic equations which is coupled with a set of time varying differential equations. In contrast ...
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In this paper application of a simulation algorithm for dynamic and nonlinear analysis of a specific liquid propellant engine is presented. The mathematical model of the engine includes a set of nonlinear algebraic equations which is coupled with a set of time varying differential equations. In contrast to the existing liquid propellant simulation algorithms, the presented work does not depend on the method of modeling. The simulation algorithm is composed of six primary steps. Comparison of the nominal values obtained from simulation with actual designed values is presented. Typical simulation outputs of primary engine variables are also given. The results of this study are used in the initial and conceptual design stages in order to advance to the other design stages.