During multi-jet cooling,the complex hydrodynamic characteristics caused by the interaction between jets will affect the heat transfer of the plate.To further clarify the heat transfer characteristics in different flo...During multi-jet cooling,the complex hydrodynamic characteristics caused by the interaction between jets will affect the heat transfer of the plate.To further clarify the heat transfer characteristics in different flow regions,the double-jet cooling experiments were completed on a 50-mm-thick plate with the initial cooling temperature and jet angle in the range of 300–900°C and 0°–60°,respectively.The inverse heat conduction was used to calculate the surface temperature and heat flux.Furthermore,the rewetting phenomenon,maximum heat flux and maximum cooling speed were studied.The results show that increasing the angle between jet and wall normal would increase the wetting front’s width downstream of the jet point.When the jet angle was 60°,the maximum value increased by 37.29 mm compared with that when the angle was 0.The correlation between the width of the wetting front and the radial temperature gradient was further confirmed.In addition,it was found that the maximum heat flux would be affected by the duration of transition boiling,but not affected by complete wetting time.The results clarified the heat transfer mechanisms under various initial cooling temperature and inclination angle conditions on plate cooling in different flow regions,and provided valuable data for controlling heat transfer efficiency and improving cooling uniformity.展开更多
In present study, double-jet precipitation method was employed to prepare the uniform AgX(X: Cl, Br, I)colloids, and then ascorbic acid/sodium borohydride was respectively used to reduce AgX into the silver nanopartic...In present study, double-jet precipitation method was employed to prepare the uniform AgX(X: Cl, Br, I)colloids, and then ascorbic acid/sodium borohydride was respectively used to reduce AgX into the silver nanoparticles(Ag NPs). The main experimental parameters about above two processes were investigated. It was found that under the same synthesis conditions the size of obtained Ag NPS was strongly dependent on the AgX size, and the silver particles obtained by reduction of AgCl, AgBr and AgI had the monotonously diminishing size order. SEM, TEM, XRD, and UV spectrometry were employed to characterize the obtained AgX and Ag NPs respectively, and they gave the size variation clearly and the mechanism was discussed.展开更多
基金the National Key Research and Development Programs of China(Grant No.2017YFB0305102).
文摘During multi-jet cooling,the complex hydrodynamic characteristics caused by the interaction between jets will affect the heat transfer of the plate.To further clarify the heat transfer characteristics in different flow regions,the double-jet cooling experiments were completed on a 50-mm-thick plate with the initial cooling temperature and jet angle in the range of 300–900°C and 0°–60°,respectively.The inverse heat conduction was used to calculate the surface temperature and heat flux.Furthermore,the rewetting phenomenon,maximum heat flux and maximum cooling speed were studied.The results show that increasing the angle between jet and wall normal would increase the wetting front’s width downstream of the jet point.When the jet angle was 60°,the maximum value increased by 37.29 mm compared with that when the angle was 0.The correlation between the width of the wetting front and the radial temperature gradient was further confirmed.In addition,it was found that the maximum heat flux would be affected by the duration of transition boiling,but not affected by complete wetting time.The results clarified the heat transfer mechanisms under various initial cooling temperature and inclination angle conditions on plate cooling in different flow regions,and provided valuable data for controlling heat transfer efficiency and improving cooling uniformity.
文摘In present study, double-jet precipitation method was employed to prepare the uniform AgX(X: Cl, Br, I)colloids, and then ascorbic acid/sodium borohydride was respectively used to reduce AgX into the silver nanoparticles(Ag NPs). The main experimental parameters about above two processes were investigated. It was found that under the same synthesis conditions the size of obtained Ag NPS was strongly dependent on the AgX size, and the silver particles obtained by reduction of AgCl, AgBr and AgI had the monotonously diminishing size order. SEM, TEM, XRD, and UV spectrometry were employed to characterize the obtained AgX and Ag NPs respectively, and they gave the size variation clearly and the mechanism was discussed.
