Experimental Study on Influence of Axial Conductive Heat on Convective Heat Transfer in Micro Steel Tube
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摘要: 以氮气为工质,流过内径为168μm、外径406μm微钢管,采用直接通电法进行加热,并使用红外成像仪加红外专用放大镜头测量了在恒定的流量下、不同加热功率以及相同加热功率、不同流量下的微钢管壁面的温度场,获得精确的微管外壁温度分布,同时测量了氮气的进出口温度和流量.根据实验结果分析了微管轴向导热对管内部对流换热的影响.研究表明,在氮气为工质下,微钢管轴向导热导致内部换热的减弱,减少量超过总对流换热量的2%.Abstract: Nitrogen gas,used as a working fluid,flows through a micro steel tube with inner diameter 168 μm and outer diameter 406 μm.Using directly electrical heating method,the outer wall temperature fields of the micro steel tube are acquired by employing an IR Camera and specially magnifying lens for constant flow rate, different heating power and constant heating power,different flow rate,respectively.The flux and the temperature of the inlet and the outlet of the micro steel tube are measured synchronously.A correlation between the axial conductive heat and the convective heat transfer is obtained by a theoretical analysis based on the experimental results.Investigations clearly show that the axial conductive heat weakens the convective heat transfer in micro steel tube and the decrement may be more than 2% compared to the quantity of whole convective heat transfer when the working fluid is nitrogen gas.
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Keywords:
- micro tube /
- axial conductive heat /
- convective heat transfer /
- IR Camera /
- temperature field
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