Study on Conjugate Heat Transfer in Electronic Equipment of Next Generation

(1)开发了三维流体流动和传热的CFD程序。利用该CFD程序，模拟了安装在封闭腔底壁上的小热源的传导和自然对流的共轭传热。在此基础上，提出了适用于共轭传热问题的有效传热面积的新概念。该计算流体动力学程序也适用于传导和强制对流的共轭传热。(2)对安装在印刷电路板上的单个热源的耦合传热进行了研究。基于有效换热面积的概念，得到了努塞尔数与雷诺数之间唯一的关联式。该关联式可以预测散热器表面的最高温度，并估算有效传热表面积，为电子设备的热设计提供依据。(3)影响传热系数的因素 关于我们 对两种情况下的流量、热源尺寸和PCB的导热系数进行了精确测量，一种是将表面积为几平方厘米的热源安装在PCB的一侧，另一种是将热源突出安装在PCB上。作为基准实验数据，这些结果可以帮助CFD设计人员开发和评估新的电子设备热设计的CFD代码。(4)测量了安装在PCB上的电子芯片模块的传热特性。一个模块封装的传热特性进行了比较，一个简单的热源安装在PCB上。明确了主要的传热路径和各路径的热阻。已被调查的建模传热路径的验证。对传热路径模型进行了修正和改进。与'CFdesign'代码得到的模拟结果进行了比较，目前的实验数据。阐明了CFdesign程序的局限性和准确性。(5)对多模块封装在PCB上的耦合传热特性进行了详细的数值研究。在此基础上，研究了模块封装间距、PCB导热系数、通道内流速等因素对有效换热面积的影响以及Nusselt数与雷诺数的关系。在此基础上，对多模块组合的优化配置进行了探讨。少

(1) 3-D CFD code for the simulation of fluid flow and heat transfer has been developed. Using this CFD code, conjugate heat transfer of conduction and natural convection from a small heat source mounted on the bottom wall of an enclosure has been simulated. Based on the numerical results, a new concept of the effective heat transfer area that is applicable to conjugate heat transfer problems has been proposed. This CFD code is also applicable to the conjugate heat transfer of conduction and forced convection.(2) Study on conjugate heat transfer of a single heat source mounted on a printed circuit board (PCB) has been carried out. Based on the concept of the effective heat transfer area, a unique correlation between Nusselt number and Reynolds number has been obtained. This correlation can predict the maximum temperature on the heat spreader surface and estimate the effective heat transfer surface area for thermal design of electronic equipment.(3) Heat transfer coefficients affected by … More the flow rate, dimensions of the heat source and thermal conductivity of PCB have been measured accurately for two cases; one for a heat source with a surface area of several square centimeters mounted on the one side of PCB, the other for a protruded heat source mounted on the PCB. As the benchmark experimental data, these results can assist CFD designer to develop and evaluate new CFD code for thermal design of electronic equipment.(4) Measurements of heat transfer characteristics of an electronic chip module mounted on the PCB have been performed. The heat transfer characteristics of a module package have been compared with a simple heat source mounted on the PCB. The main heat transfer paths and the thermal resistance of each path have been clarified. The validation of modeled heat transfer paths has been investigated. The models for heat transfer paths have been amended and improved. Simulation results obtained with the 'CFdesign' code have been compared with the present experimental data. The limitations and accuracy of 'CFdesign' code have been clarified.(5) Conjugate heat transfer characteristics for the multiple module packages mounted on a PCB have been numerically studied in details. Based on these numerical results, the effects of the interval between the module packages, thermal conductivity of PCB, and flow rate inside the duct on the effective heat transfer area and the relation between the Nusselt number and Reynolds number have been studied. Based on the above studies, the optimal arrangements of multiple module packages have been discussed. Less