Liquid Cooled High Power Aerospace Electronics Fluid Channel Layout Design Strategy Based on Analytical Calculation

This article is about the application of liquid cooling in high power aerospace electronics. This article discusses liquid cooled cold plate fluid channel layout design strategy based on hand or analytical calculations before the three dimensional thermal model is constructed. Everybody knows how to perform thermal analysis using CFD software; however, CFD software cannot generate three dimension models automatically. Thermal engineers still need to design preliminary models to analyze. CFD software cannot solve the problems for the designer. Computers cannot substitute the human in design. In the end, it is the thermal engineer’s education, experience, knowledge, strategic thinking, and know-how that determine the outcome of the design. To simplify the task, sections of the cooling channel are suggested to be designed individually to meet the cooling needs of each individual component that segment of the fluid channel is cooling. The sections of the fluid channel routed directly underneath the heat dissipating components can be connected in parallel or in series. This article will discuss the pros and cons of both design approaches. Pressure drops versus heat transfer are the tradeoffs of the fluid layout design. An example of the analytical pressure drop calculation is provided. This article also provides guidance on calculating the flow rate of each of the cooling sections and the strategy of determining the linear velocity of the liquid. In the discussion, a brief trade study of machined or casted cold plate versus tube-in-plate cold plate design is presented. Positioning of the cold plate to control the internal ambient temperature is also briefly discussed.