针对燃气透平带肋U型通道中纳米气溶胶的对流换热特性问题开展了数值研究,分析了加入纳米颗粒前后以及纳米颗粒浓度变化时气溶胶换热特性的差异,并从流场结构、气溶胶热物性、壁面边界层以及热边界层的角度探索了纳米颗粒影响对流换热的机理。结果表明:相比于空气,纳米气溶胶具有更强的换热强化性能,且加入纳米颗粒并不改变工质的基本流动规律。从气溶胶热物性来看,其换热强化能力主要源于纳米颗粒对气溶胶导热系数和热容的提升；从边界层来看,纳米颗粒通过影响湍流边界层与热边界层发展规律也对换热有所强化。虽然加入纳米颗粒引入了额外的总压损失,但其换热强化的收益要高于其引起的阻力损失。

A numerical study about the convective heat transfer characteristics of nano-aerosols in ribbed U-channels of gas turbines was carried out to analyse the differences in the heat transfer characteristics of the aerosols before and after the addition of nano-particles and when the concentration of nano-particles varies. This study explored the mechanism of nano-particles affecting convective heat transfer from the viewpoints of the flow field structure, the thermal properties of the aerosols, the boundary layer and thermal boundary layer above the wall. The results show that the nano-aerosols have stronger heat transfer enhancement performance compared with air, and the addition of nano-particles does not change the basic pattern of the air flow. From the perspective of the aerosols’ thermophysical properties, the heat transfer enhancement is mainly due to the enhancement of thermal conductivity and heat capacity of the aerosols by nano-particles; from the perspective of the boundary layer, nano-particles also enhance the heat transfer by influencing the development of the turbulent boundary layer and the thermal boundary layer. Although the addition of nano-particles introduces additional total pressure loss, the gain of heat transfer enhancement is higher than the drag loss caused by them.

国家自然科学基金(52276035)