Investigation on Cryogenic Temperature-sensitive Paint Transition Detection Technique Based on Electric Heating Film

The development of efficient and accurate transition measurement techniques is crucial for enhancing aircraft performance. To address the issues of high experimental costs, significant measurement errors, and limited continuous measurement capabilities associated with the variable total incoming flow temperature method in current domestic cryogenic wind tunnel transition measurements using temperature-sensitive paint （TSP）, a novel cryogenic TSP transition measurement technology based on electrically heated coatings is established. By optimizing the substrate material of the electrically heated coating, designing functional layers, and controlling the coordination mode and ligand energy level distribution of the TSP coating’s fluorescent probes, the compatibility and low-temperature resistance of both the electrically heated and TSP coatings are improved. Ground performance tests and cryogenic wind tunnel validations are conducted. Ground cryogenic test results indicate that the electrically heated coating surface remains crack-free in a wide temperature range of 110 K to 323 K, with a temperature rise time of less than 3 s and good heating efficiency upon energization. Cryogenic wind tunnel validations show that the transition positions obtained by the electrically heated method align well with those obtained by the variable total incoming flow temperature method, with a difference within 0. 5%. Compared with the traditional variable total incoming flow temperature method, the electrically heated method reduces the time required to obtain clear transition images from 30 s to less than 5 s per test state, significantly shortening the experimental cycle and reducing costs.