The fluid flow characteristics of the single bunch inclined jet impingement were investigated with different jet flow velocities,nozzle diameters,jet angles and jet-to-target distances for ultra-fast cooling technolog...The fluid flow characteristics of the single bunch inclined jet impingement were investigated with different jet flow velocities,nozzle diameters,jet angles and jet-to-target distances for ultra-fast cooling technology.The results show that the peak pressure varying significantly from nearly 0.5 to above 13.4 kPa locates at the stagnation point with different jet diameters,and the radius of impact pressure affected zone is small promoted from 46 to 81 mm in transverse direction,and 50 to 91 mm in longitude direction when the jet flow velocity changes from 5 to 20 m/s.However,the fluid flow velocity is relatively smaller near the stagnation point,and increases gradually along the radius outwards,then declines.There is an obvious anisotropic characteristic that the flow velocity component along the jet direction is about twice of the contrary one where the jet anlge is 60°,jet diameter is 5 mm,jet length is 8 mm and jet height is 50 mm.展开更多
Experimental results on the thermal characteristics of air-water spray impingement cooling of hot metallic surface are presented and discussed in this paper.The controlling input parameters investigated were the combi...Experimental results on the thermal characteristics of air-water spray impingement cooling of hot metallic surface are presented and discussed in this paper.The controlling input parameters investigated were the combined air and water pressures,plate thickness,water flow rate,nozzle height from the target surface and initial temperature of the hot surface.The effects of these input parameters on the important thermal characteristics such as heat transfer rate,heat transfer coefficient and wetting front movement were measured and examined.Hot flat plate samples of mild steel with dimension 120 mm in length,120 mm breadth and thickness of 4 mm,6 mm,and 8mm respectively were tested.The air assisted water spray was found to be an effective cooling media and method to achieve very high heat transfer rate from the surface.Higher heat transfer rate and heat transfer coefficients were obtained for the lesser i.e,4 mm thick plates.Increase in the nozzle height reduced the heat transfer efficiency of spray cooling.At an inlet water pressure of 4 bar and air pressure of 3 bar,maximum cooling rates670℃/s and average cooling rate of 305.23℃/s were achieved for a temperature of 850℃ of the steel plate.展开更多
基金Project(2010CB630800)supported by the National Basic Research Program of ChinaProject(N100307003)supported by the Fundamental Research Funds for the Central Universities,China
文摘The fluid flow characteristics of the single bunch inclined jet impingement were investigated with different jet flow velocities,nozzle diameters,jet angles and jet-to-target distances for ultra-fast cooling technology.The results show that the peak pressure varying significantly from nearly 0.5 to above 13.4 kPa locates at the stagnation point with different jet diameters,and the radius of impact pressure affected zone is small promoted from 46 to 81 mm in transverse direction,and 50 to 91 mm in longitude direction when the jet flow velocity changes from 5 to 20 m/s.However,the fluid flow velocity is relatively smaller near the stagnation point,and increases gradually along the radius outwards,then declines.There is an obvious anisotropic characteristic that the flow velocity component along the jet direction is about twice of the contrary one where the jet anlge is 60°,jet diameter is 5 mm,jet length is 8 mm and jet height is 50 mm.
文摘Experimental results on the thermal characteristics of air-water spray impingement cooling of hot metallic surface are presented and discussed in this paper.The controlling input parameters investigated were the combined air and water pressures,plate thickness,water flow rate,nozzle height from the target surface and initial temperature of the hot surface.The effects of these input parameters on the important thermal characteristics such as heat transfer rate,heat transfer coefficient and wetting front movement were measured and examined.Hot flat plate samples of mild steel with dimension 120 mm in length,120 mm breadth and thickness of 4 mm,6 mm,and 8mm respectively were tested.The air assisted water spray was found to be an effective cooling media and method to achieve very high heat transfer rate from the surface.Higher heat transfer rate and heat transfer coefficients were obtained for the lesser i.e,4 mm thick plates.Increase in the nozzle height reduced the heat transfer efficiency of spray cooling.At an inlet water pressure of 4 bar and air pressure of 3 bar,maximum cooling rates670℃/s and average cooling rate of 305.23℃/s were achieved for a temperature of 850℃ of the steel plate.
