Space systems design (spacecraft, satellites, space stations and their equipment)
Mohammad Reza Salimi
Volume 15, Issue 1 , March 2022, , Pages 89-105
Abstract
In present study, a hydrazine based monopropellant thruster decomposition chamber is simulated numerically. The catalyst bed separated in two sides, the particles size in upstream side is larger than those in downstream side. Effects of upstream side length and its particles diameter on catalyst bed ...
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In present study, a hydrazine based monopropellant thruster decomposition chamber is simulated numerically. The catalyst bed separated in two sides, the particles size in upstream side is larger than those in downstream side. Effects of upstream side length and its particles diameter on catalyst bed characteristics were investigated. To this end, three standard particles sizes of mesh: 16.5, 25 and 30 for the upstream side and two standard particles diameter of 1/8 and 1/16 (in) for downstream side were analyzed. Additionally, three upstream side lengths of 2.5, 5 and 7.5 (mm) were used while the length of bed is 6.5 (cm). Simulations were performed in three bed loading coefficients of 16.5, 25 and 35 (kg/m2s). The related results showed the effectiveness of upstream side on flow and thermal fields are strongly depends on the ration of particles sizes in upstream and downstream sides. Moreover, the upstream side length and bed loading are two important factors affecting the upstream side effectiveness.
Space Engineering
Mohammad N. Meibody; Hassan Naseh; Fathollah Ommi
Volume 12, Issue 4 , December 2019, , Pages 35-46
Abstract
Now, the required samples to achieve the specific precision of sensitivity analysis in design are performed based on trial and error methods. The purpose of this paper is to develop an approach for determining the number of the required sample to achieve the specific precision of sensitivity analysis. ...
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Now, the required samples to achieve the specific precision of sensitivity analysis in design are performed based on trial and error methods. The purpose of this paper is to develop an approach for determining the number of the required sample to achieve the specific precision of sensitivity analysis. Thus, in this paper, a new sensitivity analysis method is proposed based on the Progressive Latin hypercube Sampling (PLHS) and the convergence of the analysis results. For this purpose, a PLHS method has been developed. This cystic approach has led to a sensitivity analysis of accuracy, efficiency, and speed in a variety of models with a large number of large parameters and large changes. Sensitivity analysis has been performed on the design of a hydrazine monopropellant thruster catalyst bed model as a case study. The results of this study indicate that in the sensitivity analysis based on the PLHS, the minimum population required for sensitivity analysis with specified accuracy can be determined. This leads to lower processing costs in the sensitivity analysis process, especially in complex models.
