Heat Dissipation Analysis And Optimization Of Lotus Leaf-like Runner CPU Heat Sink

With the continuous increase in the demand for the computing power and computing speed of the central processing unit(CPU),the integrated density and scale of electronic devices are getting larger and larger,and the heat generation density brought by them to the chip operation increases dramatically.The high temperature caused by heat accumulation can shorten the life of electronic components and even directly destroy the electronic devices,which brings challenges to the normal operation of the CPU and its working performance.To this end,based on a review of the current state of research at home and abroad,the liquid-cooled heat sink runner is redesigned based on the vein structure of the lotus leaf,and the effect of different nanofluid and runner parameters on the performance of the CPU cooled by the imitation lotus leaf vein runner heat sink is investigated using numerical simulation analysis with nanofluid as the cooling workpiece.First,based on the rectangular heat transfer channel heat sink,the heat dissipation effect and inlet and outlet pressure loss of different particle types,base fluid types and volume fraction nanofluids were analyzed,and the results showed that the heat dissipation effect of Ag-H2 O nanofluid(5%,50 nm)was improved compared with Cu-H2 O nanofluid(5%,50 nm)and Al2O3-H2 O nanofluid 5%,50 nm)by about The heat transfer performance of glycol-based nanofluid with Cu nanoparticles is about 8.7% lower than that of water-based nanofluid,and the pressure loss of import and export is about 16.3% higher when Cu-H2 O nanofluid nanoparticle volume fraction increased from 1% to 5%,its heat transfer performance improved by about23.6%,while the inlet and outlet pressure losses increased by about 11.1%.Secondly,the heat dissipation effects of Cu-H2 O nanofluid(5%,50 nm)as the cooling medium were compared with those of a simulated lotus leaf vein flow channel heat sink,a parallel flat flow channel heat sink and a vortex flow channel heat sink with similar flow-solid heat transfer area,and then the effects of inlet flow rate and coolant temperature on the heat sink performance were analyzed based on the simulated lotus leaf vein flow channel heat sink.The results show that the maximum CPU temperature cooled by the imitation lotus leaf runner heat sink is 69.54°C,which is 36.73°C and 13.2°C lower than that of the parallel flat DC channel heat sink and scroll runner heat sink,respectively;the inlet and outlet pressure loss is 13.72 Kpa,which is 46.56 Kpa lower compared to the scroll runner heat sink,but 46.56 Kpa lower compared to the flat With the increasing coolant temperature,the maximum CPU temperature gradually increases,and the maximum CPU temperature increases at the same rate as the coolant temperature;with the increasing inlet flow rate,the maximum CPU temperature gradually decreases,but the decrease rate gradually slows down,and the pressure loss at the inlet and outlet of the heat sink keeps increasing.Finally,to further improve the heat dissipation performance of the imitation lotus leaf vein runner heat sink,the impact zone diameter,the number of leaf vein runners,the secondary runner angle,the thickness of the substrate,and the number of heat sink outlets on the performance of the heat sink were analyzed,and the results showed that:with the increase of the impact zone diameter,the maximum CPU temperature showed a trend of first decreasing and then increasing,while the pressure loss of import and export increased with the increase of the impact zone diameter With the increase in the number of runners,the maximum CPU temperature and pressure loss both show a gradual decrease;with the increase in the runner angle,the maximum CPU temperature gradually decreases,but the heat sink pressure loss gradually increases;with the increase in the thickness of the maximum CPU temperature gradually decreases,the thickness of the substrate has no effect on the heat sink pressure loss;with the increase in the number of outlets,the maximum CPU temperature and pressure loss both gradually The maximum CPU temperature and pressure loss decrease as the number of outlets increases,and the decrease gradually decreases.Meanwhile,orthogonal experiments were conducted to optimize the above factors,using the maximum CPU temperature and the pressure loss of the heat sink inlet and outlet as evaluation indicators.The results show that when the impact zone diameter is 20 mm,the number of impulse runners is 24,the secondary runner angle is 30°,the thickness of the substrate is 2 mm,and the number of outlets is 4,the overall performance of the imitation lotus leaf runner heat sink is optimal,and the maximum CPU temperature is 66.48°C and the pressure loss at the inlet and outlet is12.44 Kpa.The maximum CPU temperature is reduced by 3.06°C and the pressure loss is reduced by 1.28 Kpa.