scholarly journals The Effect of Roughness on the Rate of Ice Accretion on a Cylinder

1985 ◽  
Vol 6 ◽  
pp. 142-145
Author(s):  
Lasse Makkonen ◽  
J. R. Stallabrass
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Theoretical Model ◽  
Wind Tunnel ◽  
Empirical Data ◽  
Transfer Rate ◽  
Growth Conditions ◽  
Boundary Layer Theory ◽  
Freezing Process ◽  
Ice Accretion

The rate of icing in the wet growth conditions typical of ship icing and icing in freezing precipitation depends on the rate at which the heat liberated in the freezing process is transferred to the environment. A theoretical model for the heat transfer from the front half of a rough cylinder, based on boundary-layer theory, is described.Comparisons with empirical data show that the model simulates well the overall heat transfer rate from the front half of a cylinder with distributed roughness. The theory provides improved agreement between the results of a numerical icing model and icing wind tunnel tests.

scholarly journals The Effect of Roughness on the Rate of Ice Accretion on a Cylinder

1985 ◽  
Vol 6 ◽  
pp. 142-145
Author(s):  
Lasse Makkonen ◽  
J. R. Stallabrass
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Theoretical Model ◽  
Wind Tunnel ◽  
Empirical Data ◽  
Transfer Rate ◽  
Growth Conditions ◽  
Boundary Layer Theory ◽  
Freezing Process ◽  
Ice Accretion

The rate of icing in the wet growth conditions typical of ship icing and icing in freezing precipitation depends on the rate at which the heat liberated in the freezing process is transferred to the environment. A theoretical model for the heat transfer from the front half of a rough cylinder, based on boundary-layer theory, is described. Comparisons with empirical data show that the model simulates well the overall heat transfer rate from the front half of a cylinder with distributed roughness. The theory provides improved agreement between the results of a numerical icing model and icing wind tunnel tests.

Taylor-Goertler Vortices and Their Effect on Heat Transfer

1970 ◽  
Vol 92 (1) ◽  
pp. 101-112 ◽  
Author(s):  
P. D. McCormack ◽  
H. Welker ◽  
M. Kelleher
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Theoretical Model ◽  
Transfer Rate ◽  
Oscillatory Flow ◽  
Vortex Formation ◽  
Spanwise Direction ◽  
Concave Wall ◽  
Flow Components

An experimental measurement of the effect of Taylor-Goertler vortex formation on the heat transfer through the boundary layer on a concave wall has been made. A theoretical analysis based on independent mean and oscillatory flow components indicates that, although the heat transfer rate will fluctuate periodically in the spanwise direction, there should be no overall increase in heat transfer. The experimental results indicate that there is a significant increase in Nusselt number in the presence of the vortices. Interaction between the oscillatory and mean components must be accounted for, if the theoretical model is to be reliable.

Non-axisymmetric Homann stagnation point flow and heat transfer past a stretching/shrinking sheet using hybrid nanofluid

2020 ◽  
Vol 30 (10) ◽  
pp. 4583-4606 ◽  
Author(s):  
Najiyah Safwa Khashi’ie ◽  
Norihan Md Arifin ◽  
Ioan Pop ◽  
Roslinda Nazar ◽  
Ezad Hafidz Hafidzuddin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Strain Rate ◽  
Stagnation Point ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Hybrid Nanofluid ◽  
Ambient Fluid ◽  
Content Type ◽  
Flow And Heat Transfer

Purpose This paper aims to scrutinize the analysis of non-axisymmetric Homann stagnation point flow and heat transfer of hybrid Cu-Al2O3/water nanofluid over a stretching/shrinking flat plate. Design/methodology/approach The similarity transformation which fulfils the continuity equation is opted to transform the coupled momentum and energy equations into the nonlinear ordinary differential equations. Numerical solutions which are elucidated in the tables and graphs are obtained using the bvp4c solver. Findings Non-unique solutions (first and second) are feasible for both stretching and shrinking cases within the specific values of the parameters. First solution is the physical/real solution based on the execution of stability analysis. An upsurge of the ratio of the ambient fluid strain rate to the plate strain rate can delay the boundary layer separation, whereas a boost of the ratio of the ambient fluid shear rate to the plate strain rate only accelerates the separation of boundary layer. The heat transfer rate of hybrid nanofluid is greater for the stretching case than the shrinking case. However, for the shrinking case, the heat transfer rate intensifies with the increment of the copper (Cu) nanoparticles volume fraction, whereas a contrary result is found for the stretching case. Originality/value The present numerical results are original and new. It can contribute to other researchers on electing the relevant parameters to optimize the heat transfer process in the modern industry, and the right parameters to generate non-unique solution so that no misjudgment on flow and heat transfer features.

A Numerical Study of Impulsively Started External Convection at Microscale

2014 ◽  
Vol 31 (1) ◽  
pp. 79-90
Author(s):  
K. Ramadan
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Thermal Boundary Layer ◽  
Numerical Study ◽  
Velocity Slip ◽  
Transition Time ◽  
Surface Cooling ◽  
Linear Ordinary Differential Equations

ABSTRACTImpulsively started external convection at microscale level is studied numerically in both planar and axisymmetric geometries. Using similarity transformation, the resulting coupled partial and non-linear ordinary differential equations are simultaneously solved by finite differences together with a well established ordinary differential equation solver, over a range of problem parameters. Rarefaction effects within the slip flow regime on the thermal boundary layer response, heat transfer rate and transition time when system experiences sudden changes in surface temperature are analyzed, and a comparison between sudden surface cooling and heating is presented. The results show that the thermal boundary layer thickness, heat transfer rate and the transition time is considerably influenced by the degree of rarefaction. The transition time tends to be less sensitive with increasing rarefaction. The velocity slip and temperature jump factors are found to have opposite effects on the transition time and the heat transfer rate, with the velocity slip factor having the most profound influence on these parameters.

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