多尺度多线组宽带 k 分布模型参数优化方法

Considering the numerical calculation of remote infrared signal emitted by solid wall and hot combustion gas of jet aircraft’s transonic exhaust system， the existing multi-scale multi-group wide-band k-distribution model (MSMGWB) was expanded from 3− 5 µm wave band to 2− 2.5， 3.7− 4.8，7.7− 9.7 µm and 8− 14 µm wave bands. Moreover， the method of finding best combination of wavenumber subinterval grouping results and Gauss integral schemes was improved. The calculation results of 56 1D cases and a 3D real-structure transonic exhaust system remote infrared imaging case indicated that the optimized MSMGWB model significantly improved computation accuracy and efficiency compared with fictitious gas-based statistical narrow-band model，especially under 3− 5 µm and 3.7− 4.8 µm wave bands，the comprehensive calculation accuracy was nearly doubled，and the calculation efficiency was increased by 4 times and 1.5 times， respectively. At the same time， the optimized MSMGWB model’s comprehensive calculation accuracy was improved more significantly，and calculation efficiency was improved by about an order of magnitude compared with the domestic mainstream calculation method of target remote infrared signals.