Heataerodynamic Efficiency Of Small Size Heat Transfer Surfaces For Cooling Thermally Loaded Electronic Components

Heat transfer surfaces are widely used to ensure normal thermal conditions of heat-generating elements in radar transmit/receive modules, computing systems, power electronics, etc. The authors offer the first ever generalization of a large experimental data set on the thermal and aerodynamic efficiency of small size flat-based heat transfer surfaces (heat sinks) of various types. The paper presents a comparative analysis on the efficiency of surfaces with different types of finning (plate-fin, cross-cut, needle-pin and mesh-wire surfaces) under forced air convection. The following efficiency criteria were chosen: the surface base superheat above the ambient temperature and the complex parameter, which takes into account geometric and heat transfer characteristics of the surfaces. This complex parameter is the product of the reduced heat transfer coefficient and the finning ratio. The results on comparing the heat transfer efficiency of the surfaces according to these two criteria are presented as graphs and histograms. It is shown that the aerothermodynamic efficiency of the surface with cross-cut finning is higher than that of the standard plate and needle-pin surfaces by 1.15-1.65 and 1.8-2.0 times, respectively, and by 3.0-3.2 times compared to the mesh-wire surface. The aerothermodynamic efficiency increases due to the appearance of separated flows on the cut fin segments, a decrease in the thickness of the boundary layer on these segments, and an increase in the air flow turbulence. The developed heat transfer surfaces can be widely used in combined air cooling systems for the modern element base with an increased heat generation.