Uncertainty Analysis Of Infrared Radiation Characteristics Of Rocket Exhaust Plume

For the detection of aerial targets,especially engine plumes,infrared radiation detection is an effective means to track and identify high-speed targets.The world’s countries in the military field have focused on infrared radiation research.However,in the numerical calculation and modeling of infrared radiation,it is often a deterministic calculation that the high-speed target flight parameters and engine parameters are fixed at a certain height and at a specific time.However,high-speed target flight parameters are often changing all the time,such as a sudden increase in thrust and a sudden increase in engine combustion chamber temperature.In infrared radiation,small changes in parameters may cause large changes in infrared radiation.Therefore,the study of the uncertainty of infrared radiation characteristics and sensitivity analysis is very necessary,which can improve the credibility of the target infrared radiation,and provide reference for the subsequent modeling of the infrared characteristics of the target.In this paper,the engine exhaust plume of Atlas-II rocket is taken as the research object,aiming at establishing a set of uncertainty analysis tools for the infrared radiation phenomenon of the infrared radiation characteristics of the plume.Through the analysis and research on the uncertainty input parameters,the uncertainty is adopted.The analysis tool is used to obtain the influence of different parameters on the infrared radiation signal of the plume alone or in combination.The main work of this paper is as follows:In the calculation of the infrared radiation transmission of the engine exhaust plume,based on the radiation and flow field decoupling idea,the statistical-narrow-band(SNB)model is used to calculate the rocket engine gas plume property parameter database,using the single-line-group(SLG)band model and the view.The line-on-sight method(LOS)solves the plume radiation transfer equation and realizes the calculation of the infrared radiation characteristics of the rocket engine tail plume.A method based on PCE for numerical simulation uncertainty analysis is established.The sparse grid technique is used to solve the high dimensional "dimensional disaster" problem,and the calculation and analysis of numerical simulation uncertainty with fast,high precision and multi-parameter is realized.The PCE method is used to analyze the uncertainty of engine exhaust plume flow field,radiance brightness image and total spectral radiation intensity at typical heights(5km,25 km,50km),and the main bands(2.7μm,4.3μm and 3 ~5μm)radiation intensity was calculated and analyzed for uncertainty and sensitivity,and the influence of influencing factors on the infrared radiation signal of the plume was determined at different heights.The RSS method is used to calculate the uncertainty of the main radiation bands(2.7μm,4.3μm and 3~5μm)of the engine tail plume at typical heights(5km,25 km,50km).It is found that the method is consistent with the conclusion calculated by the PCE method.