Phase Change Technology Research And Application Of Heat Map Test

The phase change thermography technique is a wind tunnel test technique to spray some phase change paint on the aircraft surface for measuring heat distribution in a large area. Using the color changing information of phase change paint, this technique mainly applies an image capturing and processing system which consists of a CCD video camera and a computer to measure the characteristic parameter and the heat transfer rate of model surface in hypersonic flow. It is a kind of non-contact and whole-field measurement technique, which has many advantages such as fast response, high experimental efficiency, convenient operation and low cost etc. It is able to provide a great deal of information of field distribution and solve some heat transfer problems in aerodynamics or heat transfer study.This paper briefly introduces a new advance and application of phase change thermography technique in hypersonic wind tunnel of CARDC in the recent years. Many aspects, including preparing and spraying the phase change paint, improving the measurement system, developing the software of phase change digital image processing etc., are illustrated and discussed. During the test of heat distribution on a hemisphere-cylinder calibration model, the aerodynamic heat transfer measurement along model surface is obtained. We find that the result of phase change thermography was consistent with that of thermocouple technique, which shows the reliability of measurement system. Then a conclusion of heat measurement precision is calculated. Finally we can have a prospect of this research direction.