汽车空调暖风机热交换器的优化设计

Optimization design of heat exchangers in automobile air-condition

提高汽车空调性能的主要方式是提高热交换器的换热效率.由于汽车内部空间的限制,不能单纯依靠增加热交换器体积的方法来提高热效率,因此对热交换器结构优化设计将具有现实意义.利用Flnent求解和正交设计的方法对汽车暖风机热交换器进行优化设计.Fluent软件可以模拟热交换器的流动和传热过程,正交设计的方法可以建立回归方程,因此可以得到出口温度的数学模型,该模型定量地描述了翅片间距、翅片高度及水管间距对换热效率的影响,优化汽车暖风热交换器的结构,最后通过试验证明了优化设计结果的准确性.优化热交换器的结构参数:翅片间距为1.1mm,翅片高度为6.9mm,管距为5.2mm.根据Fluent模拟仿真得到出口温度的回归方程:Y=307.308+2.333X1+0.667X2+0.561X3-2.501X12,影响出口温度的因素依次为翅片间距、翅片高度和水管间距.Fluent模拟仿真和正交试验设计相结合的方法有助于产品结构分析和优化设计.

In order to improve the performance of automotive air conditioners,the best method is to escalate the heat efficiency of heat exchangers. Due to the constraints of automotive interior space,it is impossible to merely rely on increasing the volume of heat exchanger to advance the thermal efficiency,and so it is of practical significance in structural optimization and design of heat exchangers. The structure optimization design of heat exchangers can be completed by Fluent simulation and orthogonal experiment. Fluent software can simulate the heat flowing and exchanging process,and the orthogonal experiment can build regression equation. So a mathematic model can be built which can quantitatively describe the outlet temperature and exchange heating efficiency with fin pitch,fin height,tube space. In the end,experiment is done to validate the optimization design. The result shows that the optimal structure parameters of heat exchanger is 1.1 mm fit pitch,6.9 mm fin height,and 5.2 mm tube space,and the regression equation of outlet temperature is Y=307.308＋2.333X1＋0.667X2＋0.561X3-2.501X21 according to Fluent simulation,and the influence factors of outlet temperature is fin spacing,fin height and pitch pipes in turn. Combining the Fluent simulation with orthogonal experimental design is an optimal method in product structure analysis and optimization.