SOME THERMOGRAPHIC MEASUREMENTS IN COMPLEX FLUID FLOWS

Abstract

This paper deals with some thermographic measurements in complex fluid flow to measure wall convective heat fluxes. Convective heat fluxes measurement is performed by means of a thermal sensor described by a suitable heat transfer model, where proper temperatures must be measured. By correctly choosing the measuring sensor, infrared (IR) thermography can be exploited to resolve convective heat flux maps in both steady and transient techniques. If compared to standard transducers, IR camera appears very valuable because it: is non-intrusive, has a high sensitivity (down to 20mK), has a low response time (down to 20μs), is fully two-dimensional (from 80k up to 1M pixels, at 50Hz) and allows for better evaluation of errors due to tangential conduction within the sensor. This paper presents some convective heat transfer measurements in complex fluid flows performed with IR thermography by the author and his co-workers, ranging from natural convection to hypersonic regime.