Study On High Temperature Thin Film Heat Flux Sensor With New Lead Method And Its Performance

Shuttle re-entry into the earth’s atmosphere at the outer surface will produce megawatt heat flux,the instantaneous temperature rise of up to 1800℃,the serious influence of aerospace aircraft flight safety,in order to guarantee the stability of the vehicle safe operation,accurate real-time measuring aircraft surface heat flow thermal protection system for quantitative assessment of the performance and life is very urgent and important significance.,however,the traditional heat flux sensor under the condition of high temperature and strong erosion cannot work normally,this leads to the current for high temperature hot end components of surface heat flow density still is given priority to with numerical simulation and the heat conduction inverse calculation,therefore,developed a real-time,stable and accurate measurement of spacecraft components of hot end surface heat flux sensor is imminent.Aiming at the technical problem of high temperature heat flux detection,a new heat flux sensor structure which integrates lead and substrate is proposed in this paper.Specific research contents are as follows:Based on the working environment and measuring principle of the thin film heat flow sensor,a new type of high temperature thin film thermopile heat flow sensor with the integration of substrate and lead is designed,and the materials used in each structure of the thin film heat flow sensor are selected.Through ANSYS simulation software,the designed heat flow sensor is analyzed and the design parameters of the sensor are optimized.Based on ceramic powder sintering,static pressure molding and mechanical grinding,polishing and ultrasonic cleaning technology,proposed the Al₂O₃ ceramic substrate with PtRh6 lead the integration of new high temperature film heat flux sensor structure design and processing methods,break through the high temperature between inlets thin-film heat flux sensor and the signal can only rely on conductive silver glue to connect the technical bottleneck.Based on the magnetron sputtering technology,PtRh30-PtRh6 thermopile film,Al₂O₃ film and ZrO₂ film were deposited on the measurement end face of the ceramic substrate in turn.The properties of the films were characterized by SEM and EDS.The results showed that the film surface was compact and uniform,and the film composition was close to that of the target material,which met the expected experimental requirements of the high temperature film heat flow sensor.The static and dynamic characteristics of the thin film heat flux sensor are studied.The results show that the sensitivity of the thin film heat flux sensor is above 0.01μV/（W/m²）,and the dynamic response time of the sensor is 3.97s.The results show that with the increase of the thickness of the thermal resistance layer and the number of thermopiles,the output signal of the sensor increases in a certain proportion.In order to study whether the high temperature environment will affect the service performance and sensitivity of the developed sensor,a high temperature test was carried out on the sensor at 1200℃.The results show that the developed heat flow sensor has good high temperature stability and can still work normally and stably after the high temperature test.The repeatability experiment of the sensor was carried out.Through the repeatability error analysis of the experimental data,the maximum repeatability error of the sensor under the same heat flux condition was 2.38%.Through the experiment,it was concluded that the developed high temperature thin film heat flux sensor has excellent stability and repeatability.