Research On Spray Cooling System For Electronics With High Heat Flux

With the fast development of technology, decreasing size and increasing performance speed for electronics components are achieved at expense of increasing thermal dissipation. Tranditional thermal control technologies have limited removal capabilities for high power and high heat fluxes. Spray cooling is an efficient cooling techniques, which offers the ability to remove high heat fluxes, and provides uniform device temperatures. Spray cooing may be introduced into electronics with high power and high heat fluxes in the near future as an important cooling technology.So,Spray cooling has received much attention and been widely studied. In the present study, as to high power Laser-Diode Arrays(LDA'S) cooling techniques problem,required cooling system offers the bility to remove high heat fluxes≥300 W/cm2,and provides the surface temperature of heat sink between 15℃and 25℃.In this paper,experimental investigations on heat transfer in spray cooling with ammonia were conducted, using single pressure atomized nozzle and nozzle arrays in 25mm×12mm test surface. The main researches including: An spray cooling experimental system was constructed, characteristics of the single nozzle and nozzle arrays were estimated by using correlative theory research and experimental research. Second,the effect of different spray distances, spray pressure, subcool on spray cooling heat transfer performance was experimental research.Finally,the characteristics of the modularity cooling compoment and the uniformity of surface temperature distribution were tested by experimental research.The major academic achievements:①It was exhibited that ammonia is one of the best working fuilds in spray cooling.Spray cooling have excellent heat transfer performance and could be use to cool electronic components which require low surface temperature and high heat fluxes. Results demonstrated that the heat fluxes exceed 420W/cm2 with the surface temperature of heat sink being 15℃when single pressure atomized nozzle was used at spray distance of 15mm,and spray pressure of 450 kPa. The maximum heat transfer coefficient values can reach up to 95000 W/m2·K.②Spray distances and spray pressure had an significant effects on the heat transfer characteristics of spray cooling. Results show that an increased CHF and decreased surface temperature as the spray distance decreased or the spray pressure increased.③The subcool of inlet ammonia affected the heat transfer characteristics of spray cooling. Increasing subcool resulted in an increase in heat transfer coefficient and an decreased in heat transfer surface temperature.④The test shown that the modularity cooling compoment can offer the ability to remove the heat fluxes could exceed 300 W/cm2 at the surface temperature of heat sink between 15-25℃.⑤Non-uniformity of heat transfer surface temperature distribution was observed. Results shows that the temperature non-uniformity of heat transfer surface increased with the increase of heat fluxes,. The maximum temperature difference of surface reached up to±2℃when the heat fluxes was 300 W/cm2.