金刚石纳米流体强化活塞冷却油腔传热的数值模拟

Numerical on Heat Transfer Enhancement of Nanofluids for Cooling Gallery of Piston

在传统机油中添加金刚石纳米颗粒,并将其用于活塞冷却油腔散热.在传统VOF方法的基础上,引入了Level Set模型.采用两者耦合的算法考察了不同体积分数的金刚石-机油纳米流体在活塞内部冷却油腔的瞬态传热问题.结果表明,纳米颗粒的加入并没有明显改变流体机油填充率的分布.但是由于物性参数的改变,纳米机油的换热能力得到了大幅度提高.体积分数为1%、2%和3%的金刚石纳米机油与传统机油相比,整体平均对流换热系数分别提高了12.01%、29.14%和44.33%.整体计算结果与经验公式符合良好,最大误差为16.68%.

Diamond nanoparticles are added into the conventional engine oil to form a new type of nan- ofluids, which is further used as the cooling medium for piston gallery. Level Set method is introduced based on the traditional VOF method to achieve a new model. Transient heat transfer processes of diamond nanofluids with varied concentrations inside the piston gallery are discussed with a coupled arithmetic. Results show that addition of nanoparticles does not change the oil distribution obviously. However, due to the changes in the physical properties of the nano-oil, the overall heat transfer capacity is greatly im- proved. Heat transfer coefficients of diamond nano-oil with the volume fractions of l%, 2% and 3% in- crease by 12.01%, 29.14% and 44.33%, respectively. Numerical simulation agrees well with the empirical formula with maximum error of 16.68%.