STUDY ON REMOTE MEASUREMENT OF LOCAL HEAT FLUX

Research Project

Project/Area Number	61460108
Research Category	Grant-in-Aid for General Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	Thermal engineering
Research Institution	KYUSHU UNIVERSITY
Principal Investigator	FUJII TETSU INSTITUTE OF ADVANCED MATERIAL STUDY, 機能物質科学研究所, 教授 (20038574)
Co-Investigator(Kenkyū-buntansha)	SHINZATO KAN-EI INSTITUTE OF ADVANCED MATERIAL STUDY, 機能物質科学研究所, 助手 (30101463) TAKAMATSU HIROSHI INSTITUTE OF ADVANCED MATERIAL STUDY, 機能物質科学研究所, 助手 (20179550) KOYAMA SHIGERU INSTITUTE OF ADVANCED MATERIAL STUDY, 機能物質科学研究所, 助教授 (00153693) FUJII MOTOO INSTITUTE OF ADVANCED MATERIAL STUDY, 機能物質科学研究所, 助教授 (90038589)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥5,600,000 (Direct Cost: ¥5,600,000) Fiscal Year 1987: ¥1,800,000 (Direct Cost: ¥1,800,000) Fiscal Year 1986: ¥3,800,000 (Direct Cost: ¥3,800,000)
Keywords	REMOTE MEASURING METHOD / CONVECTION HEAT TRANSFER / LOCAL HEAT TRANSFER COEFFICIENT / LOCAL HEAT FLUX / 局所熱流束 / 光ファイバー / 遠隔測定法 / 対流熱伝達係数 / レーザ加熱 / 赤外線温度計
Research Abstract	The present investigation concerns with a remote method of measuring local heat flux of a heat transfer wall. The method is based on the fact that when the wall is heated locally, the temperature increment at that point depends on the local heat transfer coefficient. The degree of the dependency is, therefore, regarded as the sensitivity of the method. When a power laser and an infrared spot thermometer are used to provide local heat and measure the temperature increment, respectively, the sensitivity and accuracy of the method are investigated both theoretically and experimentally for a simple convection heat transfer system. Further is discussed its applicability to more practical and complicated systems. The main results of the present study are as follows: 1) The sensitivity varies with thermophysical properties of the heat transfer wall. It is relatively high for plastics which have low thermal diffusivity but is very low for metals. 2) The integral of the temperature increment curve is the quantity most sensitive to variation in heat transfer coefficient. If the accuracy of the integrated value is within 2 %, the heat transfer coefficient could be evaluated within 10% for acryl. For metals, however, the error is above 80 %. 3) Automatical measurement of laser heat and temperature increment with the aid of a personal computer made it possible to evaluate forced convection heat transfer coefficient of a flat plaster plate within 20 % error margin. 4) The present method differs from the conventional methods in such a way that it needs no sensor attachment to the heat transfer wall. This method would become simple and practical in roughly evaluating the local heat transfer coefficient and/or heat flux of heat transfer walls, if the accuracy of the infrared spot thermometer is improved and use of a coaxial optical fiber to power laser and infrared thermometer becomes possible.