Evaluation of Prediction Accuracy of Thermal Response of Ablator Under Arcjet Flow Condisions

Abstract

Using a cloth-layered carbon fiber reinforced plastic ablator with a specific gravity of about 1.5, the thermal response model of ablator is studied experimentally and numerically. Heating tests are carried out in the arcjet wind tunnel to quantify the thermal performance of ablator. In the tests, the surface temperatures and in-depth temperatures of ablative test pieces are measured during the testing. The experimental results obtained in the heating tests are analyzed by using a two-dimensional analysis method developed earlier. In the method, the thermal response of ablator is calculated by loosely coupling the shock layer computational fluid dynamics code and the 2-D version of ablation code using an arcjet freestream condition. The arcjet freestream condition in the test section is evaluated by calculating the flows in the arcjet wind tunnel. The present analyses are made especially focusing on an anisotropic nature of thermal conduction of ablator. Thermal conduction inside the ablator is modeled in the present analysis method based on thermal conductivity values measured for different ply angles of carbon cloths of ablator. By comparing the calculated results with the arcjet data, the prediction accuracy of thermal response models of ablator is discussed.