Heat Flux Measurement

Abstract

This chapter reviews the most useful current heat flux instrumentation, particularly heat flux gauges. It also briefly discusses the optical methods, but these are generally research methods that require sophisticated equipment and data processing techniques. General principles for the proper use of heat flux gauges are discussed first, followed by the details of specific gauges along with some of their typical applications. Three classifications of gauges are considered based on measured temperature difference over space, the temperature change with time, and the power dissipated at a maintained temperature. The measurement methods are also categorized according to the type of temperature measurement. The three common techniques are thermocouples, resistance temperature devices (RTDs), and optical. Finally, the chapter discusses the calibration of heat flux gauges along with error analysis. There are a number of problems and complications that should be taken into account while planning for any heat flux measurements.