Study On Thermal Hydraulic And Energy Saving Performance Of Pin Fin Heat Sink

With the development of microelectronic devices,personal computer and computing ability of data center,the working power of cpu chip has a big growth in these years,which makes the issue that how to dissipate heat become a hot spot.Meanwhile,heat sink was needed to reduce their volume for meeting the requirement about miniaturization and integration of computing system.Due to air cooling technology is insufficient to fulfill heat dissipation reqirement of computing system,water cooling system has started to be widely used in thermal management of computing system.In the research of water cooling system,the structural optimization of heat sink is a important research topic.How to improve the thermal hydraulic performance,guaranting the normal working condition of cpu chip while minimizing the pump power is the core part.Compare with plate-fin heat sink,pin-fin heat sink has a larger specific surface area.Furthermore,pin-fin structure is able to enhance flow turbulance and increase heat transfer coefficient.Due to aforementioned advantages,pin fin heat sink has attached wide attention in recent years.However,there are some drawbacks in the past research of pin fin heat sink.Firstly,most of studies focus on investigating the performance of cross flow cooling method,but the research about cooling with impingment jet is relatively few.Furthermore,the effect of power fluctuation on the thermal hydraulic and energy saving performance of cpu chip wasn’t taken into account.In view of the above problems,the research contents of this paper are as follows.Three heat sinks with different pin fin structure were designed and fabricated,and the test bench was built.In different working conditions,the variation of heat resistance and cpu working temperature was tested.Nusselt number and friction factor were chosen as indicators to evaluate thermal hydraulic performance,and the correlation of these two indicators were got based on the experimental data.The pattern of utilization rate of cpu chip was monitored among more than 2800 hours,and pattern of heat generation of cpu chip was got with reasonable simplification.Finally,the dynamic energy saving performance of different heat sinks was compared based on their thermal hydraulic performance and thershold of cpu working temperature.The study on thermal performance shows that the effect of flow rate on cpu working temperature is apparent in low flow rate region.The square pin fin structure shows the best thermal performance in different working conditions,and its advantage declined with the increase of flow rate.The study on hydraulic performance shows that the hydrofoil pin fin structure has the lowest flow resistance and friction factor,because of its relative steady change on channel cross-sectional area.The analysis on dynamic energy saving performance shows that the energy saving performance reduced with the increase of cpu working power,and the square pin fin structure has the best energy saving performance among three heat sinks.