Method of Heat Flux Measurement in Solid Fuel Flames Using Semiconductor Sensors

The total and radiative heat fluxes from the flame to the burning surface of a solid fuel (polymethylmethacrylate) slab for horizontal flame spread over the fuel surface were first quantitatively measured using two water-cooled miniature (2.3 x 2.3 mm) sensors mounted inside the slab. The design of the water cooling of 2 x 2 x 0.5 mm sensors (greenTEG AG) allows their placement directly in the combustion zone. Radiative heat flux was measured by a sensor with a protective ZnSe window, and the total heat flux was measured by a similar sensor without a protective window. The conductive heat flux determined using sensors was compared with that calculated from the data of polymethylmethacrylate flame temperature measurements using thin thermocouples. The maximum radiative and total heat fluxes from the flame to the polymethylmethacrylate surface measured by the heat flux sensors were 30-35 and 70-75 kW/m2, respectively.