This paper deals with the evolution of infrared (IR) thermography into a powerful optical tool that can be used in complex fluid flows to either evaluate wall convective heat fluxes or investigate the surface flow field behavior. Measurement of convective heat fluxes must be performed by means of a thermal sensor, where temperatures have to be measured with proper transducers. By correctly choosing the thermal sensor, IR thermography can be successfully exploited to resolve convective heat flux distributions with both steady and transient techniques. When comparing it to standard transducers, the IR camera appears very valuable because it is non-intrusive, it has a high sensitivity (down to 20 mK), it has a low response time (down to 20 μs), it is fully two dimensional (from 80 k up to 1 M pixels, at 50 Hz) and, therefore, it allows for better evaluation of errors due to tangential conduction within the sensor. This paper analyses the capability of IR thermography to perform convective heat transfer measurements and surface visualizations in complex fluid flows. In particular, it includes the following: the necessary radiation theory background, a review of the main IR camera features, a description of the pertinent heat flux sensors, an analysis of the IR image processing methods and a report on some applications to complex fluid flows, ranging from natural convection to hypersonic regime.

/pdf/infrared-thermography-for-convective-heat-transfer-56a0bwe7om.pdf

Infrared thermography for convective heat transfer measurements

Jet impingement heat transfer on a flat plate at a constant wall temperature

Numerical analysis of turbulent convection heat transfer from an array of perforated fins

Heat transfer analysis of lateral perforated fin heat sinks

Thermal enhancement from heat sinks by using perforated fins

An experimental study on hot round jets impinging a concave surface

Local heat transfer due to several configurations of circular air jets impinging on a flat plate with and without semi-confinement

Experimental heat transfer on the windward surface of a perforated flat plate

A heat transfer measurement of jet impingement with high injection temperature

Study of the influence of the number of holes rows on the convective heat transfer in the case of full coverage film cooling

Jean-Jacques Vullierme

Papers

An experimental study on hot round jets impinging a concave surface

Local heat transfer due to several configurations of circular air jets impinging on a flat plate with and without semi-confinement

Experimental heat transfer on the windward surface of a perforated flat plate

A heat transfer measurement of jet impingement with high injection temperature

Study of the influence of the number of holes rows on the convective heat transfer in the case of full coverage film cooling