Development Of Film Radiation Heat Flow Meter

During the process of science and technology, industrial production and engineering construction, heat flux is transmitted in varied modes, and three commonest transmission modes are thermal conductivity, convection and radiation. As the development of the modern science and technology, the heat flux density measuring technology has earned more and more attention. In the field of thermal analysis and monitoring, the necessity of heat flux density measuring has earned high emphasis and confirmation, and the corresponding heat flux measuring methods have been greatly developed and widely applied. In the aspect of radiation heat flux density measurement, a lot of new type sensors have been developed at abroad, and the research and manufacturing of new materials have provided technical support for it, however, it still keeps relatively laggard. This thesis focuses on the analysis and research of the development of film radiation heat flux sensor with the polyimide as substrate by adopting the magnetron sputtering film coating process and photoetching technology, and the main contents include:Compare the measuring methods of radiation heat flux density, make the measuring head with the thermoelectric pile type temperature different measuring plan to meet the requirements of small and simple structure, analyzes the influences to measuring result with physical parameters and geometric dimension. After analyzing, this thesis produced the result when the thermal conductivity coefficient ? and the thermoelectric coefficient e0 of the material are fixed, the lower the thickness of thermal resistant layer ?x, the less the response time ?, however, it may also increase the measuring head coefficient C, the low output potential E under same heat flux density makes against the measurement. In order to solve this problem, this thesis amplies the output signal through increasing the series-connected thermocouples without increasing the complication of the device.Take polyimide as the substrate, this thesis has developed three models of film radiation heat flux sensors with the magnetron sputtering film coating and photoetching technology. The size of the measuring head is 2×2cm, and the thermocouple quantity for the thermoelectric pile are 20 pairs,10 pairs and 5 pairs respectively. One set of test bench which is used for calibration is constructed, and the calibration and response test are performed for the measuring head of three models of sensors. The calibration result shows that the linear extraction of three samples are excellent, when the quantity of thermocouples is in multiple, the output voltage is also amplified in multiple, the measuring head coefficient is 91.188W/(m2·?V),182.366W/(m2·?V) and 350.699W/(m2·?V) respectively, the error with the theoretic value is:7.75%,6.94%, 2.82%, respectively. It is shown in the response test result that the response time ? of three samples is 67ms,78ms,90ms respectively. Finally, this thesis has analyzed the error during calibration and response test, and concluded that the output voltage fluctuation of the sensor measuring head is mainly caused by air turbulence, the error during response test is mainly caused by interference of the arm movement of the operator. The sensor conformity test result shows that the measuring head conformity is excellent with the process described in this thesis.