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首页> 外文会议>HTD-vol.376-2; ASME(American Society of Mechanical Engineers) International Mechanical Engineering Congress and Exposition; 20051105-11; Orlando,FL(US) >CHANNEL SIZE BASED MEASUREMENT TECHNIQUES FOR CONDENSATION HEAT TRANSFER COEFFICIENTS IN MINI-AND MICRO-CHANNELS
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CHANNEL SIZE BASED MEASUREMENT TECHNIQUES FOR CONDENSATION HEAT TRANSFER COEFFICIENTS IN MINI-AND MICRO-CHANNELS

机译：基于通道尺寸的微型和微通道冷凝水传热系数的测量技术

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摘要

A set of techniques for the measurement of condensation heat transfer coefficients for circular and noncircular channels with 5 mm > D_h > 100 μm is presented. For the larger range of D_h (5 > D_h> 0.4 mm), single tubes or multiple parallel extruded channels are used as test sections. The test section is cooled using water at a high flow rate to ensure that the condensation side presents the governing thermal resistance. Heat exchange with a secondary cooling water stream at a much lower flow rate is used to obtain a large temperature difference, which is used to measure the condensation duty. Condensation heat transfer coefficients are measured in small quality increments for 0 < x < 1 over the mass flux range 150 < G < 750 kg/m~2-s with uncertainties typically less than 20%. For 200 > D_h > 100 μm, channels are fabricated on a copper substrate by electroforming copper onto a mask patterned by X-ray lithography, and sealed by diffusion bonding. Subcooled liquid is electrically heated to the desired quality, followed by condensation in the test section. Downstream of the test section, another electric heater is used to heat the refrigerant to a superheated state. Energy balances on the pre- and post-heaters establish the refrigerant inlet and outlet states at the test section. Water at a high flow rate serves as the test section coolant to ensure that the condensation side presents the governing thermal resistance. Heat transfer coefficients are measured for 200 < G < 800 kg/m~2-s for 0 < x < 1. It is demonstrated that uncertainties as low as 6% can be achieved in the measurement of condensation heat transfer coefficients.
机译：提出了一套用于测量5 mm> D_h> 100μm的圆形和非圆形通道冷凝水传热系数的技术。对于较大的D_h范围（5> D_h> 0.4 mm），将单个管或多个平行挤压通道用作测试段。使用高流速的水对测试部分进行冷却，以确保冷凝侧具有控制热阻。与次级冷却水流以低得多的流速进行热交换，以获得较大的温差，该温差用于测量冷凝负荷。在质量通量范围150 D_h> 100μm时，通过将铜电铸到X射线光刻图案化的掩模上，在铜基板上制造通道，并通过扩散结合进行密封。将过冷的液体电加热到所需的质量，然后在测试部分中冷凝。在测试部分的下游，使用另一个电加热器将制冷剂加热到过热状态。预热器和后热器上的能量平衡确定了测试部分的制冷剂入口和出口状态。高流量的水用作测试部分的冷却剂，以确保冷凝侧具有控制热阻。当传热系数为200

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