年間 4 号発行
ISSN 印刷: 1065-3090
ISSN オンライン: 1940-4336
Indexed in
VISUALIZATION OF TURBULENT HEAT TRANSFER TO A WATER FLOW IN A CIRCULAR PIPE USING HIGH-SPEED INFRARED THERMOGRAPHY
要約
Visualization and measurement of the spatial-temporal heat transfer characteristics of a turbulent water flow were conducted in a horizontal acrylic circular pipe, using a high-speed infrared thermograph (frame rate of up to 800 Hz). The inner diameter of the pipe was D = 20.4 mm and the Reynolds number varied from 1000 to 38,700. The test surface for the heat transfer measurement was fabricated from 22-µm-thick titanium foil coated with black paint, which was heated electrically with a constant heat flux. The heat transfer coefficient was evaluated quantitatively through heat conduction calculations for the heated surface considering the thermal inertia and diffusion. From the results of the present measurements, the convection pattern of high heat transfer spots was elucidated through frame-by-frame imaging of the instantaneous distribution. Also, the convection velocity was estimated from a 2D autocorrelation of the streamwise-temporal distribution. The convection velocity normalized by the mean velocity in the pipe was uc/um = 0.5−0.8 and that normalized by the friction velocity was uc+ = 10−14.
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SHIIBARA Naoki, NAKAMURA Hajime, YAMADA Shunsuke, Quantitative measurement of heat transfer fluctuation in a pipe flow around an orifice plate using high-speed infrared thermography, Mechanical Engineering Journal, 2, 6, 2015. Crossref
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SHIIBARA Naoki, NAKAMURA Hajime, YAMADA Shunsuke, Relation between the positions of flow reattachment and maximum heat transfer at downstream of an orifice in a pipe, Transactions of the JSME (in Japanese), 82, 840, 2016. Crossref
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Nakamura Hajime, Shiibara Naoki, Yamada Shunsuke, Quantitative measurement of spatio-temporal heat transfer to a turbulent water pipe flow, International Journal of Heat and Fluid Flow, 63, 2017. Crossref
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Shiibara Naoki, Nakamura Hajime, Yamada Shunsuke, Unsteady characteristics of turbulent heat transfer in a circular pipe upon sudden acceleration and deceleration of flow, International Journal of Heat and Mass Transfer, 113, 2017. Crossref