To solve the problem that existing k distribution model is not suitable for high temperature flow 3-5μm wave band emission radiation transmission attenuation characteristic in atmospheric long distance calculation

multi-scale multi-group technology used in full-spectrum model before was applied in wideband model

and the grouping state points on the spectral absorption coefficient were adjusted.The calculation results of one-dimensional/quasi one-dimensional numerical example of infinite width multilayer gas radiation characteristics show that multi-scale multi-group technology can improve the calculation precision of original full spectrum and wideband model while keeping compatibility with rational of gray wall. On this basis

the coupling heat transfer characteristics and the remote infrared characteristics of V nozzle trailing edge contraction with cooling device were studied. The results show that the gas radiation effect on the solid wall temperature distribution in the nozzle can not be ignored. The prediction error of the remote infrared images for transonic exhaust system at 70km with use of the multi-scale multi-group wideband model is about 7%.