Numerical Simulation Of Scramjet Flowfield And Thermal Radiation

Owing to small size, high speed and wide work space, the Ramjet is viewed as the preferred power plant for near space hypersonic flight and has widely application in military field and aerospace industry.At present, the literature involving the research of radiation heat transfer combustion chamber and infrared radiation characteristics of ramjet exhaust plume is rare. However, it is reasonable to carry out such study for the thermal protection, in future the infrared detection and stealth design research.In this thesis, taking into account of multi-step chemical reaction mechanism of combustion and the influences of turbulence and particle phase, scramjet combuster, nozzle and trail flame flow field are numerically simulated using Fluent CFD software, and flow field data under various fuels and flight conditions are obtain. Based on the above work, the numerical model of infrared radiation characteristics of ramjet exhaust plume is developed and computational studied. The distributions of radiant heat flux of combustion chamber wall surface, infrared radiation characteristics and spectral distribution property under various conditions are obtained for Billing type scramjet. The main content of the paper is as following.(1) Simulation of flow field and radiative heat transfer of Billing type scramjet.Based on multi-step chemical reaction mechanism of combustion, numerical results of the flow field of combustion chamber are obtained and the calculated results are in accord with experimental data This thesis also analyzes the flow field of combustion chamber of Billing type ramjet under different Mach number, both the fuel of Hydrogen and kerosene. Combined the discrete ordinate method(DOM) with combined wide and narrow band correlated k-distribution model(CWNBCK), the radiative heat transfer in chamber is calculated to obtain the raditive heat flux on the chamber wall. (2)Simulation of Billing type scramjet nozzle and exhaust plume flow field and infrared signatureTaking into account of the recrudescence process, this paper numerically analyzes the tail flame flow field parameters under different March number both the fuel of Hydrogen and kerosene. Based on the above research, the radiation characteristics parameters of flow field are calculated by narrow band model, the SIRRM model are employed to calculate the infrared characteristics of exhaust plume, and infrared intensity and radiation brightness is achieved under various conditions.