【作者】 周伟；

【导师】 李夔宁；

【作者基本信息】 重庆大学 ， 动力工程及工程热物理， 2013， 硕士

【摘要】 汽车散热器作为发动机冷却系统的重要组成部分，主要作用是通过金属扁管和翅片将冷却系统的循环介质在发动机舱吸收的热量传递给外部环境，以维持发动机冷却系统有效循环，保证发动机的正常工作。本文基于JB/T8577-2005、JIS D1614-2000等工业标准，研制了一种以测量散热量和阻力压降为目的的高精度汽车散热器性能试验台。试验台主测为空气侧，采用焓差法测定散热能力。试验台在空气侧设计增加了取样装置，以对进口空气温度进行测量；试验台风道系统采用插入式多喉颈流量计和文丘里流量计组合的方式对空气流量进行测量，不仅保证了测量精度和准确度，也提高了测量范围。试验台辅测为介质侧，采用比热容法测定散热能力。试验台在介质侧设计增加了一个有压力标准接头和铂电阻温度传感器标准接头的取样装置，以方便温度和压力测量，减小连接管路对压力测量的影响。通过与出厂试验数据的对比可知：试验数据准确有效、真实可靠，性能试验台能够应用于汽车散热器的工程实际。考虑到汽车散热器工作时冷却介质和空气流动为非接触交叉流动，即通过扁管和翅片外表面进行热交换，这样只要建立准确的数学模型，就可对不同扁管数目，不同翅片形式散热器进行方法相同的仿真计算。本文以百叶窗翅片汽车散热器为研究对象，以矩阵实验室为基础，编写根据汽车散热器计算长度确定出口状态参数为迭代算法的性能仿真程序，对仿真程序进行可视化界面设计以完成散热器传热和压降的仿真模型。通过仿真与试验结果对比可知：仿真结果与试验结果在空气侧散热量相对误差<3.5%，介质侧散热量相对误差<3.1%，空气侧压降相对误差<7.2%，介质侧压降相对误差<8.9%。随着汽车产业的发展，散热装置在节省材料方面越来越被重视，要求汽车散热器的开发设计是最优的可行方案。本文通过矩阵实验室脚本文件编写散热器优化程序，利用遗传算法以百叶窗开窗间距、百叶窗开窗角度，百叶窗翅片间距、翅片厚度、扁管厚度、扁管管壁厚度为优化变量，对汽车散热器进行优化设计。结果表明：在保证散热量和阻力压降满足设计要求情况下，相比于原散热器优化后散热器耗材面积减少了5.8％左右；在耗材面积一定和阻力压降满足设计要求情况下，相比于原散热器优化后散热器的散热量提高了4.2%左右。更多还原

【Abstract】 As an important part of engine cooling system, the main function of automobileradiator is to release heat that absorbed from the engine nacelle by flat pipe and fin. Itcan not only make the cooling system maintain effective cycle but also ensure thenormal work of the automobile engine.A high precision property test bed which was used to measure thermal dissipationand pressure drop of automobile radiator was designed on the basis of JB/T8577-2005and JISD1614-2000. As main measurement test, the air side is to use enthalpydifference method to calculate the thermal dissipation capacity. A sampling device wasdesigned to measure the inlet air temperature; for the duct system, the measurementaccuracy and measuring range are improved by using the venturi meter and multiplethroat diameter flow meter. As auxiliary measure test, the medium side is to adoptspecific heat method to measure the thermal dissipation capacity. A sampling devicewas designed with pressure standard connector and platinum resistance temperaturestandard connector to minish the effect of connecting line on the pressure drop, it is alsoconvenient to measure temperature and pressure. It was proved that the experimentaldata was in good agreement with the normal data, the property test bed can be used inpractical projects about automobile radiator.Considering the cooling medium and air are noncontact, the heat exchangehappened only on the surface of the flat tubes and fins when automobile radiator isworking, as long as an accurate mathematical model was established, the simulation canbe carried out in the same way about radiators with different type of fins and flat tubes.In this article, a complete mathematical model about automotive radiator with louveredfin has been established on the basis of theoretical analysis and experimental data, thesimulation program and simulation model have been compiled with matrix laboratoryby an iterative algorithm that according to the gauge length to determine the dischargestate of automotive radiator. It was proved that the simulation results were in goodagreement with the test results, the heat exchange relative error of air side was lessthan3.5%, the heat exchange relative error of medium side was less than3.1%, thepressure drop relative error of air side was less than7.2%, the pressure drop relativeerror of medium side was less than8.9%. With the development of automobile industry, the consume materials have to meetmore strict demands, and an optimal feasible programme is required for automobileradiator. This article choose script file of matrix laboratory to knit optimization programand then the genetic algorithm is applied to optimize the louver pitch, shutter angle, finpitch, fin thickness, flat tube thickness and flat tube wall thickness. It is proved that theoptimized area is about less5.8%than original area on the premise that thermaldissipation capacity and pressure drop meet the standard; the thermal dissipationcapacity is about more4.2%than original thermal dissipation on the premise thatpressure drop meet the standard and certain radiate area.更多还原