Heat flux measurements are often needed in thermal studies and
have been widely used for engineering and research applications
[1–8], for example, building and environmental studies, fire safety,
electronic systems, material structures, combustion chambers and
engines, and aerospace applications. Heat flux measurements are
important for controlling heating processes, to assess device performance at high temperatures, to optimize systems for energy
production and for designing the thermal protection systems for
combustors in industrial and power engineering projects. The
interests in the measurements of unsteady heat transfer phenomena was increasing due to the need to understand the heat transfer
process occurring in inherently unsteady environments. Transient
heat flux measurements were widely needed in applications including high enthalpy plasmas, high power pulsed lasers, structural
thermal tests and other fields. The well-established single-point heat
flux gauges are widely available for various applications in thermodynamics and fluid. Measurement techniques of single-point heat
flux, for example, null-point calorimeters, thin-film gauges, coaxial
thermocouples, Schmidt–Boelter gauges, and Gardon gauges, have
been developed to measure heat fluxes in various types of thermal
environments