纳米流体绕包裹泡沫金属圆管外流动换热的数值模拟

Numerical Simulation of Nanofluid Flow and Heat Transfer Around Solid Cylinder Wrapped with Metal Foam

对纳米流体横掠包裹泡沫金属的圆管进行了二维数值模拟,研究了纳米流体与泡沫金属的双重强化换热作用。通过模拟出的流场及温度场分析泡沫金属包裹厚度、雷诺数Re和纳米流体浓度对换热和阻力系数的影响,对比纳米流体与水、泡沫金属管与光管换热的效果。模拟结果表明:包裹泡沫金属的单管换热效果比普通光管好,纳米流体使换热得到有效强化,随纳米流体体积分数增大,其换热系数比水的换热系数高出2%-15%。在研究范围内,Nu数随包裹泡沫金属厚度增加而增大1.4倍-2.2倍,由纳米流体所引起的压降变化不大,而包裹厚度的增加导致压降增幅较大。

In this paper,nanofluid flow and heat transfer around solid cylinder wrapped with metal foam has been simulated.The influence of Reynolds number and volume fraction of nanofluid as well as the thickness of metal foam wrapped from is examined through the analysis of flow field and temperature field. Effects of different fluids and cylinders on flow and heat transfer are also analyzed.The numberical results show that： the presense of solid clinder wrapped with metal foam has better effect on heat transfer than ordinary cylinder.Nanofluid enable enhance heat transfer and the heat transfer is 2%-15%times than water with the volume fraction increases.Within the scope of the study,Nusellt number increases when thickness of metal foam wrapped increases,it is about 1. 4times- 2. 2times than cylinder without metal foam. The pressure drop caused by the nanofluids changes slightly,but increases a lot when the thickness increases.