Research And Analysis Of Uncertainty Quantification Methods For Aircraft Propulsion Systems

The special design structure of the hypersonic vehicle with integrated flight/propulsion makes the subsystems of the vehicle highly coupled with each other.The large airspace,high hypervelocity,and long-range flight environments result in a large amount of time-variability and uncertainty in the overall performance of the vehicle.It is mainly reflected in the time-varying nature caused by large airspace flight,hypersonic airflow,fuel consumption leading to changes in vehicle mass,etc.Uncertainties such as scarcity of test data,elastic-plastic changes in materials,and interference by random factors.This paper takes an aspirated hypersonic vehicle as the research object,combines uncertainty quantification theory,studies and analyzes the influence of uncertainty factors in the vehicle propulsion system on the propulsion performance,and uses sensitivity analysis to analyze the uncertainty factors affecting the vehicle propulsion performance,providing theoretical support for the design and optimization of complex systems considering uncertainty.The main points include the following.(1)The uncertainties in the analysis of practical engineering problems and the uncertainties in hypersonic vehicle propulsion systems are studied,and the uncertainties are classified and summarized from multiple perspectives and quantitative analysis methods based on stochastic uncertainties and cognitive uncertainties are briefly described.(2)Stochastic uncertainty quantification methods,including Monte Carlo method,higher-order statistical moment method and generalized polynomial chaos method,are analyzed,and the computational efficiency,experimental accuracy,experimental samples and engineering applicability between the three are compared by arithmetic examples.(3)In studying the influence of input parameters on system performance,a semi-global sensitivity analysis method based on variance is investigated and compared with the traditional sobol’ sensitivity analysis method.The experimental results demonstrate that the computational accuracy of the two methods is comparable,but the former method outperforms the latter in terms of computational efficiency and information representation.(4)The uncertainty quantification method and sensitivity analysis method have been applied to establish a set of theories to quantify uncertainty in complex systems,and the uncertainty quantification of hypersonic vehicle propulsion system has been completed.It is proved that the proposed theoretical method has good applicability in the practical problems of aircraft,and provides a theoretical basis for the study of uncertainty quantification of complex systems.