Development of a new high performance heat exchanger using a surfactant water solution

使用表面活性剂水溶液开发新型高性能热交换器

• 批准号: 12650199
• 负责人: KUMADA Masaya
• 金额: $ 2.3万
• 依托单位: Gifu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650199/
• 关键词: Tom's effect; Drag redaction; Heat transfer enhancement; Turbulence promoter; Performance evaluation based on a constant pump power; Surfactant solution; Heat exchanger; 三角リブ

An experiment was conducted to investigate the drag-reduction and the heat transfer characteristics in a surfactant water solution flow. It was confirmed that the percentage of the drag-reduction was more than 70 % and simultaneously, the heat transfer coefficient was reduced at the same rate. In order to promote the heat transfer for the surfactant water solution flow, an enhancement method using a triangular rib was proposed. Comparing with the case without rib, it was found that the dependence of the drag-reduction and the heat transfer characteristics on Re and C was similar, but the critical Reynolds number at which the drag reduction reaches a maximum was smaller. Further, by the performance evaluation based on a constant pump power, it was verified that the compound method by the surfactant and the triangular rib is effective to improve the performance of heat exchangers.To investigate the temperature dependence of the Tom's effect, measurements of velocity and temperature profi … More les in a two-dimensional channel were done as parameters of inlet velocity, temperature of the working fluid and wall surface. It was found that the velocity profiles vary clearly with temperature of the wall surface as comparing with the temperature profiles. However, the Tom's effect does not stop working, when the temperature in the thermal boundary layer is that it stops working. The Tom's effect is very sensitive for the temperature, on the other hand it is suggested that the varying process is complex.The rate of drag reduction of a single pipe with, roughness surface using the air-conditioner was measured, because the triangle rib as mentioned above is too expensive to apply to a real-product heat exchanger. It was found that the appearance of the Toms effect is observed as similar with previous results. As concerning the heat exchanger, the rate of drag reduction of the radiator on the market with using roughness pipe is measured. It is decreased by the header part of the radiator, however the roughness pipe is still useful for the drag reduction. Less

对表面活性剂水溶液流动中的减阻换热特性进行了实验研究。结果表明，减阻率在70%以上的同时，换热系数也有不同程度的降低。为了强化表面活性剂水溶液流动的换热，提出了一种三角肋强化方法。结果表明，Re和C对减阻和换热特性的影响相似，但减阻达到最大值的临界雷诺数较小。此外，通过恒定泵浦功率下的性能评价，验证了表面活性剂与三角肋片复合的方法对提高换热器性能的有效性。为了考察TOM效应的温度依赖性，测量了速度和温度分布…以进口速度、工质温度和壁面为参数，在二维流道内进行了较多的大涡模拟实验。结果表明，速度场随壁面温度变化明显，与壁面温度场相比，速度场有明显的变化。然而，当热边界层中的温度是TOM停止工作时，TOM的效应并不停止工作。TOM效应对温度非常敏感，但变化过程比较复杂。由于上述三角肋片的成本太高，无法应用于实际产品换热器，因此测量了带有粗糙表面的单根管材在空调机上的减阻率。结果发现，TOMS效应的出现与前人的结果相似。对于换热器，测量了市场上使用粗糙管的散热器的减阻率。它被散热器的集管部分减小了，但粗糙管仍然对减阻有用。较少