Best Engineering Practices to Establish Cooling Limit for 375W Add-in PCI-e Center Accelerator Card with Active Optical

There are many widely available heat transfer technologies that use forced air and vapor chambers to solve thermal problems up to 40 Watts/cm². The chart in Figure 1 provides an overview of today's cooling technologies, markets, and total device power in Watts while introducing heat flux limits in W/cm² for air cooling versus liquid cooling. The present study investigates the characterization of an air-cooled 375 W add-in PCI-e Card with active optical modules based on a computational fluid dynamics (CFD) model at different airflow rates. The numerical model correlates the thermal performance of a FPGA chip with test data from a Dell R740 chassis. Using Ansys IcePak V19.1 software [1], a series of CFD simulations has been performed to determine the temperature and flow fields over a range of airflow rates. In order to validate the computational model findings, experiments were conducted to obtain the airflow and pressure drop values at different flow rates using an Air Movement and Control Association (AMCA) standard wind tunnel. It was determined that the PCI-e card test data correlated with the numerical model and that the limitations of existing air-cooled heatsinks can be extended by including a textured surface as detailed in a patent by Refai-Ahmed et al. [2] on the base of the heatsink. Hence, the thermal interface material (TIM1.5) between the silicon chip and the textured surface can be represented at 70 microns thickness with an effective thermal conductivity of 20 W/m-K which has a higher overall performance.