Uncertainty analysis of infrared thermography in convective heat transfer

Infrared thermography is the preferred choice in many industrial processes for thermal diagnostics, condition monitoring, and non-destructive testing. However, the inherent uncertainty of surface emissivity affects the accuracy of temperature measurement by infrared thermography. In this paper a comprehensive experimental investigation was conducted to assess the uncertainty of infrared thermography in convective heat transfer. Four convective heat transfer conditions, including natural and forced convection on a flat plate, were studied. A composite test plate was constructed with an embedded heater and thermocouples. The thermocouples were used as references to compare with measurements by the infrared camera. The results indicate that the uncertainty of temperature measurement is about 4°F (2.7 % of the wall-to-ambient temperature difference) with the largest uncertainty being contributed by calibration of the infrared camera. The uncertainty of the heat transfer coefficient is 4.2% which is largely contributed by wall temperature measurement. Copyright