A New Calibration Technique for Thin-Film Gauges and Coaxial Thermocouples Used to Measure the Transient Heat Flux

Research on a dedicated thin-film thermocouple testing system for transient temperature measurement

“…The adaptive filter proposed in this study flexibly switches between data-smoothing and fast-tracking states by changing the variance R value of the measurement noise in a timely manner through a real-time computation method, which in turn provides a timely correction of the Kalman gain K t . As shown in (10), summarize the error squares between the measured and estimated values during the kth filtering iteration as well as its previous m time consecutive filtering iterations, then divide by m + 1, yields J(k). This expression is taken as a switching criterion for the parameter R of the Kalman filter, where i takes the range of [k−m,k], and the measured and estimated values at the ith iteration is denoted as z (i ) and x (i )…”

“…Thin-film thermocouple (TFTC) utilizes the Seebeck effect for temperature measuring, with the thickness of thermal junction on the order of microns [7]. TFTC are characterized by small size, small heat capacity, short thermal response time, high accuracy, high sensitivity, low interference and damage to the measured target and test environment, and are suitable for occasions with narrow space and difficult installation [8][9][10].…”

“…Since the film thickness and sputtering process of TFTC could affect the sensitivity coefficient of the finished product [17], the Seebeck coefficients of TFTC are different and somewhat nonlinear from those of filament thermocouples of the same material, and need to be re-calibrated after preparation in order to obtain an indexing table [10]. Therefore, the drawback of these devices is that the utilization of the average Seebeck coefficient of a standard thermocouple instead of the nonlinear Seebeck coefficient of a TFTC for amplification and coldjunction compensation could reduce the measuring accuracy.…”

High Temperature Heat Flux Sensor With ITO/In2O3 Thermopile for Extreme Environment Sensing

“…There are many types of conventional HFSs, such as Gardontype sensors [5][6][7] , Schmidt Boelter sensors 8 , and gradient-type heat flow sensors [9][10][11] ; However, the presence of traditional HFSs can bring large errors to the measurement environment due to their large size and complex installation, such as the introduction of flow field disturbance; in addition, they generally can only work at limited temperatures or heat flux densities and have a long response time 12 . Compared to the above types of heat flux sensors, thin-film heat flux sensors have attracted more research interests due to their small size, thin thickness and fast response [13][14][15] , especially the thermopiletype thin film heat flux sensors, which have a great advantage in high-temperature harsh environments.…”