管内疏水壁面纳米流体的传热与减阻特性研究

Studies on heat transfer and fluid dynamic characteristics of internal nanofluids flow with hydrophobic channel wall

中文关键词: 纳米流体，微纳结构，疏水壁面，强化传热，流动减阻

英文关键词: nanofluid  micro-nano structure  hydrophobic tube  convection  heat transfer enhancement

中文摘要:

      纳米流体强化对流传热的同时，往往不可避免地增加流动阻力，这将增大泵功，造成能量的浪费。疏水壁面具有减阻的特性，将纳米流体与疏水壁面相结合，试图达到既强化传热，又减小流动阻力的目的。多数的疏水壁面制备工艺，仅可处理小尺寸的平直壁面，，而无法在面积和曲率较大如管路内壁面做疏水处理。利用简单的置换反应方法，辅以低表面能苯甲酸修饰剂，制备得到了疏水的铜管内壁面。纳米流体在疏水壁面的对流传热和流动阻力实验结果表明，体积浓度2.000%的SiO2/DI-water纳米流体，可将对流传热系数提高18.10%，同时使达西摩擦系数降低4.9%。纳米流体和疏水壁面的搭配组合，是推动纳米流体在传热领域中广泛应用的有效方案。

英文摘要:

      Nanofluids for heat transfer application suffer from inevitable pump power consumption. The hydrophobic treatment for heat transfer surface may be a prospective strategy to achieve heat transfer enhancement and flow resistance reduction. However, the limitations of hydrophobic treatment technique and process make it difficult to fabricate desirable large size hydrophobic surface. A facile displacement reaction method is applied to prepare the lath-like silver crystals and micro-nano gaps in the inner surface of copper tube with assistance of benzoic acid dispersant. The result shows that the convective heat transfer coefficient increases to 18.10% and the Darcy friction factor decreases to 4.9% at the volume concentration of 2.000% when SiO2/DI-water (Deionized water) nanofluids flow through the hydrophobic surface. The hydrophobic surface-assisted strategy provides an effective scheme for wide applications of nanofluids in heat exchange equipment.