Luminescent thermometry for aerodynamic measurements

Abstract

A luminescent temperature sensitive paint containing the molecule rhodamine B base in a silicone polymer paint has been developed that utilizes video imaging detection to produce temperature maps of an entire surface from luminescence intensity measurements. The luminescent thermometry system has been calibrated in the laboratory to have an intensity loss of 2.30% per °C, in the range of 10 to 46 °C, with a root mean square prediction error (RMSPE) of 0.26 °C. To evaluate the technique, transient temperature field measurements have been made on a copper plate with a heater at one end. In spite of a loss in sensitivity of the paint due to aging effects that reduced sensitivity to 1.39% intensity loss per °C, the calculated RMSPE was 0.25 °C and the time series of temperature profiles predicted from luminescence agree with those predicted by a numerical solution to the heat flow equation. Data was also collected from the surface of an airfoil in a wind tunnel experiment. In spite of systematic temperature differences between the thermocouples used for calibration and the paint, RMSPE’s of less than 1 °C were obtained.