交变磁场下磁纳米流冷却液强化柴油机缸盖微区域冷却  

Magnetic nanofluid cooling liquid strengthens local cooling of diesel engine cylinder head under alternative magnetic field

作　　者：郑伟[1] 林育兹[2] 苏忠根[3] 

机构地区：[1]厦门大学嘉庚学院,漳州363105 [2]厦门大学,厦门361005 [3]温州大学瓯江学院,温州325035

出　　处：《农业工程学报》2015年第4期69-75,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助(51105184);浙江省自然科学基金资助(LY13E06009)

摘　　要：为能实现柴油机缸盖鼻梁微区域高效冷却兼顾节能化的要求,该文提出了一种通过外部施加交变磁场的方式促进磁纳米流内粒子的微运动达到强化传热的方法,并与传统乙二醇冷却液、Cu-乙二醇纳米流冷却液进行了柴油机缸盖鼻梁微区域传热效果的对比研究。结果表明:在0.17 Hz的磁场交变频率影响下,磁纳米流中加热棒温度值最大下降幅度提升了29.3%,内部粒子运动涡数增加。缸盖鼻梁微区域试验表明:相比传统乙二醇冷却液,稳态工况下,最大扭矩工况点和标定工况点处测点温度值最大下降幅度分别约为12%、14.4%,外特性工况下测点平均温度值降幅为23.7℃,约为9.4%。瞬态工况测试结果表明,采用交变磁场影响下的磁纳米流冷却液,柴油机预热时间较采用传统乙二醇冷却液和Cu-乙二醇纳米流冷却液分别缩短了9.8%和8.2%,柴油机急加速工况下能保持冷却液温度波动性小。能耗率计算结果表明,采用外部施加交变磁场加强磁纳米流冷却液高效传热的方式在达到相同冷却液温度时,可实现节能幅度为7.2%。该研究为柴油机乃至其他高温部件的节能化高效冷却提供科学参考。Using some different ways to strength the local heat transfer ability of diesel cylinder head has some research productions, such as optimization of cooling fluid flow path, using more efficient cooling liquid, and using split cooling systems to meet demands of different positions of diesel engine. However, the effect of the first method seems limited, the results of the second method have been notoriously divergent, and the original intention of the third method is to increase intake flow. Some researchers put forward an idea that uses the nanofluids with jet impingement technology to improve the performance of heat transfer of diesel engine cylinder head, but this method has high energy consumption and cylinder head has been changed big too much. This paper attempts to use magnetic nanofluids with external alternation magnetic field to improve the heat transfer performance of diesel cylinder head at nose bridge area, based on two main reasons, one is nanofluid coolant has good heat transfer characteristics and the other is magnetic field changing enhances the nanometer particle moving trend. Based above reasons, this paper made some basic researches aiming to find out whether external alternative magnetic field can better improve moving trend of magnetic nanometer particles or not, furthermore, applying the above basic research results to a diesel with split-type cooling system to explore whether external alternative magnetic field can improve the heat transfer performance of diesel engine cylinder head or not, using traditional glycol, Cu-glycol nanofluid coolant and magnetic Fe3O4 nanofluid coolant, respectively. The results of this study showed, with the effect of external alternation at 0.17 Hz frequency, the eddy number of magnetic nanofluid coolant was increasing obviously and the heat transfer performance of nanofluid coolant was improved, and the biggest incline range of temperature value of heating rod was caused, which was 17.2%. The temperature test of cylinder head bottom showed that, compared with

关 键 词：柴油机 冷却 传热 缸盖 局部冷却 磁性纳米流 试验 节能 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]