活塞环-气缸套纳米润滑油强化传热的机理研究

Research on the mechanisms of heat transfer improvement of nano-lubricants for piston ring-cylinder liner

中文关键词: 活塞环-气缸套  纳米润滑油  多相流  计算流体力学

英文关键词: piston set-cylinder liner  nano-lubricants  multiphase flow  computational fluid mechanics

中文摘要:

      内燃机活塞环-气缸套之间润滑油膜存在流体润滑、薄膜润滑以及干摩擦状态共存的现象。针对其中的流体润滑状态,采用Euler-Lagrange算法考察了加入纳米颗粒后对基础润滑油传热性能的影响。结果表明由于纳米颗粒的加入对流场产生扰动,表现为速度边界层减薄,加速了润滑油与壁面热量传递过程,显著提高了润滑油的换热能力。以体积分数为0.5%、1%和1.5%、粒径为50纳米的金刚石纳米润滑油为例,相对于基础润滑油,平均对流传热系数分别提高了2.5%、5.4%和7.3%。

英文摘要:

      The lubricants for piston ring-cylinder liner have several states, such as hydrodynamic lubrication, thin-film lubrication and dry friction. Under the condition of hydrodynamic lubrication, the influence of nanoparticles on the heat transfer property was studied by Euler-Lagrange method. The results showed that the addition of nanoparticles apparently increased the lubricant heat transfer capacity by thinning the velocity boundary layer and speeding up the heat exchange process between lubricants and walls. For nanofluids containing 0.5%, 1.0% and 1.5% diamond nanoparticles by volume, the average heat transfer coefficient is respectively 2.5%, 5.4% and 7.3% higher in comparison with the case of lubricants only.