Abstract: Based on the conjugate gradient method (CGM), a heat flux identification method for reentry vehicle structures is proposed. A one dimensional structure is firstly adopted as the research object to verify the effectiveness of the proposed heat flux identification method. The influences of both the temperature dependent thermal properties of the material and the measurement error of the sensors on the identification accuracy are analyzed. Then, the heat flux identification analysis for the thermal protection structure and complex reentry capsule is presented. Research results indicate that the proposed method could effectively identify the heat flux of thermal protection structure and reentry capsule structure. When the nonlinearity caused by the thermophysical parameters of the material is considered in the identification process, the accuracy of the identified results could be improved by updating the sensitivity during the calculation. When the sensor has a large measurement error, by using the noise reduction method and the convergence criteria, the over fitting phenomenon can be solved, and the identification accuracy can be improved.

Key words: Reentry vehicle, Thermal protection structure, Heat flux identification, Conjugate gradient method