纳米流冷却液射流方式强化缸盖局部冷却的试验分析  

Analysis of strengthening local cooling on diesel cylinder head using nano-fluids with jet impingement technology

作　　者：郑伟[1,2] 苏忠根[1] 张振东[2] 程强[2] 

机构地区：[1]温州大学机电工程学院,温州325035 [2]上海理工大学机械学院,上海200093

出　　处：《农业工程学报》2013年第8期69-77,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助(51105184)

摘　　要：为解决柴油机缸盖高热密度区域的冷却问题,本文采用射流方式的纳米流对其进行强化冷却。通过配置不同体积比的Cu、MgO、Al2O3纳米流,对自制的带有射流装置的柴油机缸盖进行传热性能对比研究。结果表明,与传统冷却液水相比,射流方式下3种纳米流冷却液均能不同程度地提升缸盖高热密度区域的传热性能,局部最大增加比率超过110%;在体积比≤2%时,3种纳米流冷却液射流传热系数都呈现出随粒子浓度的增加而增加的趋势,但随浓度的进一步增加反而降低;3种纳米流冷却液的射流传热系数随射流速度的增加而增加,但MgO纳米流在低射流速度下的射流传热系数最小,甚至比传统冷却液低2%～4%;3种纳米流冷却液的射流传热系数随射流高度的增加而增加,但射流高度过高会减小射流传热系数;随射流角度的增加射流传热系数也增加,射流角度的降低不仅降低射流传热系数还会加重测试点温度不一致的现象,过低射流角度时测试点温度值最大差距近30℃;射流传热系数随射流初始温度的增加而增加,但65℃之后,传热系数则随着射流初始温度的升高而下降;随着粒子浓度增高,电动泵消耗功率随之增加,本试验最大功率损耗为115W。本文的研究成果是一种柴油机冷却技术的应用基础研究,可为实现缸盖局部高热密度区域的良好散热提供一种新的科研思路。Diesel engines, as an important power source for machinery, are increasingly subject to people’s attention. Only with better cooling systems can they put up better work performance. Because coolant flow in the cylinder heads is difficult, how to better cool this part is becoming a hot point in the researching world. To solve the problem of cooling the high heat density areas in diesel cylinder heads, our study used nanofluids with jet impingement technology, due to better capacity of heat transmission of nanofluids and better capacity of local cooling of jet impingement technology. Thoroughly configuring different volume ratios of nanofluids, using the nanoparticles Cu, MgO, and Al 2 O 3 , we researched the change regulation of the heat transfer ability of diesel cylinder heads with self-made jet impingement equipment. The results showed that, compared with traditional coolant, using three kinds of nanofluids with jet impingement can enhance the heat transfer performance several degrees at high heat density areas in the cylinder heads. With proper setting of the jet impingement parameters, the largest local ratio increase was 110%. Different volume ratios of nanofluids took different variation trends of the heat transfer coefficient. In the volume ratio of less than 2%, the jet heat transfer coefficient of nanofluids decreased with particle concentration, and with the further increase of particle concentration the heat coefficient continued to decrease. This increase in nanoparticles increased the viscosity level of the nanofluids, resulting in decreased fluid flow. With the increase of jet velocity, the heat transfer coefficient of the nanofluids increased, but the heat transfer coefficient of MgO was the lowest at low-speed, even lower than traditional coolant at 2% ~ 4%; the viscosity number of MgO nanofluids was the largest, so too low of a jet speed can make fluid flow difficult. With the increasing jet height, the heat transfer coefficient of nanofluids also increased, but the exorbitant jet height was co

关 键 词：柴油机 冷却 传热 纳米流 试验 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]