Mixed convection cooling of a cylinder using slot jet impingement at different circumferential angles

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• 作者：S. Naderipour ; T. Yousefi ; M. Ashjaee ; D. Naylor
• 刊名：Heat and Mass Transfer
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：52
• 期：8
• 页码：1443-1453
• 全文大小：2,605 KB
• 刊物类别：Engineering
• 刊物主题：Engineering Thermodynamics and Transport Phenomena
  Industrial Chemistry and Chemical Engineering
  Thermodynamics
  Physics and Applied Physics in Engineering
  Theoretical and Applied Mechanics
  Engineering Fluid Dynamics
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-1181
• 卷排序：52

文摘

An experimental study using Mach–Zehnder interferometer has been carried out to investigate the heat transfer from an isothermal horizontal circular cylinder, which is exposed to an air slot jet at different angles of jet impingement. A square edged nozzle is mounted parallel with the cylinder axis and jet flow impinges on the side of the cylinder at angles Θ = 0°, 30°, 60° and 90°. The Reynolds number varied from 240 to 1900 while the Grashof number and slot- to cylinder-spacing is kept constant at Gr = 22,300 and H/w = 7 respectively. The Richardson number varied from 0.006 to 0.4. The flow field is greatly influenced by the slot exit velocity and the buoyancy force due to density change. The local Nusselt number around the cylinder has been calculated using the infinite fringe interferograms at 10° intervals. Average Nusselt number shows that heat transfer is decreased when the angle of jet impingement is increased.List of symbolsDDiameter of the cylinder (m)GrGrashof number (Ra/Pr)HDistance between nozzle exit and cylinderkThermal conductivity (W/m K)Nu_θLocal Nusselt numberNu_aveAverage Nusselt numberPPressure (Pa)PrPrandtl number (ϑ/α)r0Radius of the cylinder (m)RaRayleigh number [gβ(T_w − T_∞) D3/ϑα]ReReynolds number (UD/ϑ)RiRichardson number (Gr/Re2)TTemperature (K)UAverage jet exit velocity (m/s)WNozzle width (m)