Multi-objective trade-off analysis of an integrated cold gas propulsion system

Abstract

The overall design of cold gas propulsion systems is pretty complicated when considering the mission requirements, operating constraints and functional limitations imposed by the mechanical components. To address this complication, a precise design process is proposed, which attempts to optimize the cost of operation as well as to minimize the waste volume and weight by using multi-objective trade-off analysis. This analysis is based on a set of ordinary differential equations that are solved iteratively to describe the optimal behavior of the system. Therefore, a numerical code is being developed to give insight on the design sensitivity with respect to uncertainties on the design variables. Consequently, the most favorite operating media, nozzle inlet pressure and tank charging pressure are determined. Moreover, the advantages of electric heater for the storage tank are studied for a specified mission. A three-dimensional computational fluid dynamics analysis is employed to accurately simulate the flow conditions inside the nozzle. The accuracy of the simulation is verified by correlation with experimental results obtained from a non-vacuum test set-up. The experimental results have revealed acceptable performance and agreement with the simulation, within 7% in error.