Abstract
Heat transfer fluctuation between fluid and solid has a possibility to cause problems related to wall temperature fluctuation, such as high cycle thermal fatigue of materials. Also, the heat transfer enhancement due to flow turbulence has a similarity to the mass transfer enhancement, which leads to "flow accelerated corrosion (FAC)" at downstream of an orifice in pipe flows. In order to avoid and/or predict these phenomena, the quantitative information is necessary on the spatio-temporal fluctuation of the heat transfer. In this work, a technique using high-speed infrared thermography was applied to measure the spatio-temporal heat transfer to a turbulent water pipe flow having an orifice plate (bore ratio d/D=0.49). The spatio-temporal distribution of the heat transfer coefficient was evaluated from the temperature fluctuation on the heated thin-foil measured using high-speed infrared thermograph (〜800 Hz). As a result, it was demonstrated that the quantitative measurement was possible using this technique, not only for the time-averaged heat transfer, but also for the spatio-temporal fluctuation.
