Design and Experimental Study of Spherical Calorimeter in Arc-Heated Wind Tunnel

In order to improve its performance and reduce the cost, hypersonic vehicle urgently needs to design the thermal structure with low redundancy. This requires the ground electric arc heating test to be more closer to the real aerodynamic thermal environment of the aircraft with better accuracy and repeatability. The surface heat flux density of the model is the important basis for determining the surface ablation state and total heat addition in the test parameters. In particular, the accuracy and repeatability of the heat flux density on the model surface directly affect the ablation and thermal insulation performance of the models. Therefore, it is necessary to accurately monitor and measure the heat flux density of model surface during long time ground assessment test in arc-heated wind tunnel. In this paper, based on the conventional water calorimeter measurement principle, combining with theoretical analysis, we design a new type spherical water calorimeter, which can measure the sum of spherical heat addition and stationary point heat flux density of the model. The internal cooling structure of spherical water calorimeter is optimized by means of three-dimensional heat transfer structure optimization, and the experimental verification is carried out. The results show that the quantity of the calorimeter with good accuracy and repeatability. This calorimeter can get the stationary point heat flux of the model during the long time test, and can diagnose the parameter fluctuation of the flow field in arc-heated wind tunnel.