Davood Ramesh; Sajad Khodadadiyan; Hasan Karimi
Volume 9, Issue 1 , May 2016, , Pages 1-11
Abstract
The purpose of this paper is to present a genetic algorithm (as a software) to optimize engine main parameters through the application of "genetic algorithm" and also introduced the new and modified thermodynamic cycles with analysing their performance. This software objective function is to achieve ...
Read More
The purpose of this paper is to present a genetic algorithm (as a software) to optimize engine main parameters through the application of "genetic algorithm" and also introduced the new and modified thermodynamic cycles with analysing their performance. This software objective function is to achieve the highest and optimum level of 'final velocity'. In this study, the strategy of using fuel booster turbopump and 2nd stage fuel pump is followed primarily to moderate the effect of cavitation on pumps. Although the use of boosterpumps increase the weight, arise pumps' rpm and possibility to reduce the tanks pressure came with a decrease in weight of propulsion system. The developed software is applied to Russian RD-180 engine in construction of propulsion system of first stage of ATLAS IIIB LV, and experimental results have been demonstrating the improvement of engine performance which results from a multi-variable sensitivity study on a staged-combustion engine will be highlighted. This algorithm is under the limitation of constraints to control the critical variation of combustion pressure, turbine rpm, and pumps cavitation margin and turbine temperature. Results show that, supply flow rate of gas generation from 2nd stage of fuel pump and divide flow rate of exhaust of fuel booster turbine to 2nd stage of fuel pump and combustion chamber, will increase the final velocity of launch vehicle.
A. Jafarsalehi; M. Mirshams; R. Emami
Volume 7, Issue 1 , April 2014, , Pages 1-12
Abstract
This paper focuses upon the development of an efficient method for conceptual design optimization of a satellite. There are many option for a satellite subsystems that could be choice, as acceptable solution to implement of a space system mission. Every option should be assessment based on the different ...
Read More
This paper focuses upon the development of an efficient method for conceptual design optimization of a satellite. There are many option for a satellite subsystems that could be choice, as acceptable solution to implement of a space system mission. Every option should be assessment based on the different criteria such as cost, mass, reliability and technology contraint (complexity). In this research, mass and technology constraints, which have a direct impact on the satellite life cycle cost, are considerd as system level objective function to obtain the system optimal solution during the coceptual design phase. The approach adopted in this paper is based on a distributed collaborative optimization (CO) framework. At system level, multiobjective optimization goal is to minimize the dry mass of the satellite and, simultaneously, minimize the system technology complexity which is subject to equality constraints. The use of equality constraints at the system level in CO to represent the disciplinary feasible regions, introduces numerical and computational difficulties as the discipline level optima are non-smooth and noisy functions of the system level optimization parameters.To address these difficulties robust optimization algorithms such as genetic algorithms (GA) are used at the system level. The results show that the CO framework has the same level of accuracy as the conventional All-At-Once approaches.
M. Ebrahimi; J. Jodey; J. Roshanian
Volume 1, Issue 1 , September 2008, , Pages 47-56
Abstract
Abstract-Multidisciplinary Design Optimization (MDO) approaches have significant effects on aerospace vehicle design methodology. In designing next generation space launch systems, MDO processes will face new and greater challenges. Needs to improve conceptual design capabilities have required an increase ...
Read More
Abstract-Multidisciplinary Design Optimization (MDO) approaches have significant effects on aerospace vehicle design methodology. In designing next generation space launch systems, MDO processes will face new and greater challenges. Needs to improve conceptual design capabilities have required an increase in the fidelity of empirical disciplinary models, improved design solutions and optimization methods, and reduced workload and design cycle time through advanced frameworks. Such a procedure could identify feasible designs and generate comparison and sensitivity data during optimization.This study uses a System Sensitivity Analysis method to optimize multidisciplinary design of a two-stage Small Solid Propellant Launch Vehicle (SSPLV) based on minimum launch mass. Suitable design variables and technological and functional constraints are considered, both at the system and discipline levels. Propulsion, weight, geometry and trajectory simulation disciplines are used in an appropriate combination. A Generalized Sensitivity Equation (GSE) is derived and solved, and the results of this equation are used for optimization. Comparing the results with the well known gradient based optimization methods proves the ability of the SSA method to reduce computation time.
