Optical flow diagnostics

Temperature sensitive paint

We have developed a new class of Temperature Sensitive Paint (TSP) in collaboration with colleagues at IIT Kanpur. TSP contains an active luminophore molecule. The molecule reaches a higher electronic level by absorbing a particular wavelength of light. It emits light back at a longer wavelength, whose intensity depends on the surface temperature. A priori calibration allows the temperature to be retrieved from the intensity captured by a charge-coupled device (CCD) camera. The most crucial variable in the Indian context is that all known TSPs were developed abroad, and their composition, coating, and data acquisition/analysis methods remain confidential. 

All the processes, from TSP preparation to data analysis, are developed in-house. Indian raw materials are only used in every process to ensure self-reliance. Multiple Indian patents and peer-reviewed journal/conference publications acknowledge the usage of the paint. In the current form, it can 1) detect laminar to turbulent flow transition and 2) quantitatively measure spatial heat flux. We believe that our diagnostic tool helps in the design of future low-drag airplanes, interplanetary, and atmospheric re-entry missions. Scientists from VSSC, ISRO, and NAL received hands-on training on our paint usage.