Application of Curve Fitting Extrapolation in Measuring Transient Surface Temperature

The engine inner wall surface temperature was measured by the plug blind-hole extrapolation, and multiple thermocouples were installed at different depths in the substrate. The engine wall extrapolation model of transient high temperature was established according to the basic principles of heat transfer. The transient temperatures were measured by thermocouples buried at different depths of the engine wall and fitting curve was got. The transient temperature field which was generated by the three oxy-hydrogen flame guns was used to simulate the transient high temperature field inside the engine wall. The simulated inner wall surface temperature curves of the engine could be got by the curve fitting extrapolation of temperature sensor and the infrared thermometer respectively, which show good agreement in the overall trend and at the peak point, and verify the correctness of the extrapolation model and method.