scholarly journals Влияние периодической макрошероховатости на развитие турбулентной свободной конвекции у внезапно нагреваемой вертикальной пластины

2022 ◽  
Vol 48 (3) ◽  
pp. 47
Author(s):  
А.М. Левченя ◽  
Е.М. Смирнов ◽  
С.Н. Трунова
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Free Convection ◽  
Convective Flow ◽  
Heated Plate ◽  
Checkerboard Pattern ◽  
Free Convective Flow ◽  
Differential Model ◽  
Significant Intensification ◽  
Range Of Variation

The results of numerical simulation of unsteady free convection developing near a suddenly heated plate, on which protrusions in the form of adiabatic cylinders of double height with respect to the diameter are arranged in a checkerboard pattern, are presented. The calculations were performed according to the Reynolds equations using a differential model of turbulent stresses. The range of variation of the Grashof number (plotted according to the thickness of the free convective flow), in which a significant intensification of heat transfer can be achieved, has been determined. It is shown that the best conditions for intensification are created if the longitudinal pitch in the array of protrusions is approximately twenty times the diameter of the latter.

Frost Formation on Vertical Cylinders in Free Convection

1982 ◽  
Vol 104 (1) ◽  
pp. 3-7 ◽  
Author(s):  
C. J. Cremers ◽  
V. K. Mehra
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Growth Rates ◽  
Convective Flow ◽  
Vertical Cylinder ◽  
Free Convective Flow ◽  
Frost Formation ◽  
Vertical Cylinders ◽  
Frost Growth

Frost growth on a cooled vertical cylinder in free convective flow was studied experimentally. A correlation that is based on heat transfer considerations was found to be effective in predicting frost growth rates particularly at relative humidities equal to or greater than 65 percent and growing times equal to or greater than 60 min.

An Experimental Investigation of Heat Transfer and Buoyancy Induced Transition from Laminar Forced Convection to Turbulent Free Convection over a Horizontal Isothermally Heated Plate

1978 ◽  
Vol 100 (3) ◽  
pp. 429-434 ◽  
Author(s):  
H. Imura ◽  
R. R. Gilpin ◽  
K. C. Cheng
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Forced Convection ◽  
Leading Edge ◽  
Finite Amplitude ◽  
Heated Plate ◽  
Transfer Rates ◽  
Longitudinal Vortices ◽  
Turbulent Flow Regime ◽  
Laminar Forced Convection

The flow over a horizontal isothermally heated plate at Reynolds numbers below that at which hydrodynamic instabilities exist, is characterized by a region of laminar forced convection near the leading edge, followed by the onset of longitudinal vortices and their growth to a finite amplitude and finally a transition to a turbulent flow regime. Results are presented for the temperature profiles, the thermal boundary layer thickness, and the local Nusselt number. They are used to identify the various flow regimes. It was found that the transition from laminar forced convection to turbulent convection was characterized by the parameter Grx/Rex1.5 falling in the range 100 to 300. For values of this parameter greater than 300 the heat transfer rates were independent of Reynolds number and typical of those for turbulent free convection from a horizontal surface.

Sign in / Sign up

Export Citation Format

Share Document