Design, Fabrication and Calibration of Heat Transfer Gauges for Transient Measurement

Transient measurements of surface heating rates are very important in many applications in the field of internal combustion engines, gas turbine engines, fluidized beds and high-speed flow environments. In most surface heat transfer mapping, very fast response sensors are used for dynamic temperature measurements in the flow. The surface heat fluxes are then estimated from the temperature history, analytically/numerically by various heat transfers modeling. Thin film gauges and thermocouples are most cost effective temperature sensors for dynamic measurements because the response time of these sensors are in the range of microseconds. The production of heat transfer gauges in the laboratory has always been an art rather than a method of manufacture. The present work is aimed at design and fabrication of fast response thermocouples and thin film gauges (TFG) in the laboratory. Three types of thermocouples have been fabricated (E-type, T-type and K-type) whereas platinum film is deposited on the insulating substrate (Pyrex and Macor) for thin film heat transfer gauge. Both thermocouples and thin film gauges are calibrated under same experimental conditions.