Free Surface Impinging Jet

More documents

Recommendations

Info

Conclusions•It was found that the laminar parabolic velocityprofile gives the highest Nusselt number. Hence,once should use the nozzle exit condition that wouldproduce the parabolic velocity profile in order toachieve better heat transfer performance•The unsteady-state simulation of a free surfaceliquid layer penetrates a stagnant liquid layer ofdepth 1mm in order to reach the thermally activeimpingement surface has been carried out. Thewhole process only takes less than 0.2s to reachsteady state. The air bubble is entrained andtrapped when liquid jet hitting stagnant liquid layer.The air bubble has potential risk to deteriorate heattransfer performance.
Conclusions•Analytically, the stagnation region of axisymmetric jets issolved as a special case of the Falkner-Skan similarityanalysis. It is dropping the y-momentum term in Navier-Stokes equation, and converting the x-momentum term fromthe parabolic PDE to become ODE. However, in the jetimpingement flow, as the flow approach the stagnation zone,it will be decelerated in axial direction and accelerated inradial direction simultaneously. The region of changing flowdirection, especially near the nozzle edge, the flow direction isnot pre-dominantly in radial direction. Hence, the completemathematical analysis should not neglect the y-momentumequation. As can be shown from the CFD Volume of Fluidnumerical simulation, at the region about r/D ≈ 0.5 and z/D >0.04, the local axial velocity relative to resultant velocity isgreater than 0.1. This imply that the axial velocity component(y momentum equation) cannot be neglected
Page 1 and 2: Free Surface Impinging JetWork done
Page 3 and 4: Introduction - Application• Verti
Page 5 and 6: Literature Review - FreeSurface Imp
Page 7: Mathematical Modelling - FreeSurfac
Page 10 and 11: Validation of laminar flow field in
Page 12 and 13: Heat transfer under free surfaceimp
Page 16 and 17: F'''Heat transfer under free surfac
Page 20 and 21: Heat transfer under partial submerg
Page 22 and 23: Heat transfer under partial submerg
Page 26 and 27: References1. Womac, D.J., Ramadhyan
Page 28 and 29: References9. Stevens, J., Pan, Y.,

Free Surface Impinging Jet

Create successful ePaper yourself

Delete template?

Save as template?