Heat transfer and friction in turbulent vortex flow

1959 ◽  
Vol 8 (1) ◽  
pp. 457-473 ◽  
Author(s):  
Frank Kreith ◽  
David Margolis
Keyword(s):  
Heat Transfer ◽  
Vortex Flow ◽  
Turbulent Vortex

FORCED CONVECTION BASED HEAT TRANSFER ANALYSIS OF SPHERICAL DIMPLE AND PROTRUSION SURFACE IN TURBULENT FLOW

2017 ◽  
Vol 41 (5) ◽  
pp. 771-786 ◽  
Author(s):  
Ashif Perwez ◽  
Shreyak Shende ◽  
Rakesh Kumar
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Vortex Flow ◽  
Rectangular Channel ◽  
Heat Transfer Analysis ◽  
Flow Structures ◽  
Transfer Enhancement ◽  
Heat Transfer Augmentation ◽  
Thermal Boundary Conditions

An experimental and numerical investigation is performed to study the effect of dimple and protrusion geometry on the heat transfer enhancement and the friction factor of surfaces with dimples and protrusions subjected to turbulent flow. The parameters used to compare the spherical dimples and protrusions are Nusselt Number, friction factor, and flow pattern. These parameters are obtained for a Reynolds number of 10500-60900. The spherical dimple results showed the greater heat transfer, which is about 6.97% higher and pressure loss which is 5.07% lower than the spherical protrusion. The realistic heat transfer augmentation capabilities of channels with dimples and protrusions can be studied from the experimental results. The comparison is made with respect to the smooth rectangular channel under the same flow and thermal boundary conditions. The numerical analysis is performed which shows the different vortex flow structures of the spherical dimples and protrusions channel.

Slit Aspect Ratio Effect on Flow Instability and Heat Transfer Characteristics of Wavy Vortex Flow

2019 ◽  
Vol 44 (9) ◽  
pp. 7767-7777 ◽  
Author(s):  
Dong Liu ◽  
Siliang Sun ◽  
Shicheng Ding ◽  
Nana Kofi Amponsah-Gyenin ◽  
Hyoung-Bum Kim
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Vortex Flow ◽  
Flow Instability ◽  
Heat Transfer Characteristics ◽  
Ratio Effect ◽  
Transfer Characteristics

Thermal Behaviors in a Solar Air Heater Channel with Arc-Shaped Baffle Turbulators

2014 ◽  
Vol 1051 ◽  
pp. 845-849
Author(s):  
Narin Koolnapadol ◽  
Yingyong Kaewkohkiat ◽  
Pongjet Promvonge ◽  
Smith Eiamsa-ard
Keyword(s):  
Heat Transfer ◽  
Channel Wall ◽  
Vortex Flow ◽  
Longitudinal Vortex ◽  
Solar Air Heater ◽  
Thermochromic Liquid Crystal ◽  
Absorber Plate ◽  
Thermal Behaviors ◽  
Air Heater ◽  
Smooth Channel

Influences of arc-shaped baffles turbulators (ASB) on thermal behaviors in a solar air heater channel are studied. In the experiment, the ASB with three pitch ratios (P/e) are placed on the absorber plate (bottom channel wall in this case) to generate stronger turbulence intensity in the channel. The distributions of temperature and local Nusselt number contours in the absorber plate fitted with ASB are observed with thermochromic liquid crystal (TLC) sheet. The results reveal that the heat transfer increases with the decrease in P/e due to longitudinal vortex flow effect. The heat transfer from employing the ASB at P/e = 4.0, 6.0 and 8.0 is higher than the smooth channel around 116%, 120% and 127%, respectively. This indicates that the ASB pitch spacing is optimal at 8 times baffle height in the present work.

Hypersonic Viscous Shock Layer Calculation of Leeward Vortex-Induced Heat Transfer on a Sharp Cone at a High Angle of Attack

1977 ◽  
Vol 99 (2) ◽  
pp. 307-313 ◽  
Author(s):  
J. C. Adams
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Shock Layer ◽  
Vortex Flow ◽  
Local Heating ◽  
Three Dimensional ◽  
Leeward Side ◽  
Heating Rates ◽  
Viscous Shock Layer ◽  
Sharp Cone

An analysis technique applicable to the problem of leeward vortex-induced heat transfer on a sharp cone at high angles of incidence under hypersonic laminar flow conditions is presented. The analysis, a three-dimensional hypersonic viscous shock layer approach in conjunction with a numerical solution procedure, is shown to be both applicable and accurate based on comparisons of heat-transfer distributions, surface pressure distributions, and leeward meridian flow-field profile measurements taken in a hypersonic wind tunnel. Detailed calculations of the embedded vortex flow field on the leeward side of the cone are presented in such a manner as to clearly portray exactly how embedded vortex flow influences local heating rates.

Effect of divider wall-to-end wall distance on the vortical structures and heat transfer characteristics of two-pass channel using topological analysis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhiqi Zhao ◽  
Lei Luo ◽  
Dandan Qiu ◽  
Songtao Wang ◽  
Zhongqi Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Vortex Flow ◽  
Topological Analysis ◽  
Three Dimensional ◽  
Separated Flow ◽  
Heat Transfer Characteristics ◽  
Content Type ◽  
Serpentine Channel ◽  
Transfer Characteristics ◽  
End Wall

Purpose This study aims to explore the 3 D separated flow fields and heat transfer characteristics at the end wall of a serpentine channel with various turn clearances using topological analysis and critical points principles of three-dimensional vortex flow. Design/methodology/approach This aims to explore the 3 D separated flow fields and heat transfer characteristics at the end wall of a serpentine channel with various turn clearances using topological analysis as well as critical points principles of three-dimensional vortex flow. Findings The endwall heat transfer in the narrow spacing passage is significantly stronger than that in a wide spacing channel. As the gap clearance is kept at 0.87 times of the hydraulic diameter, the endwall heat transfer and thermal performance can be accordingly enhanced with low pressure drops, which is because a relatively strong concentrated impingement flow for the medium gap clearance helps to restrain the downstream fluid flow and enhance the shear effect of the secondary flow. Practical implications The numerical results can be applied in designing sharp turn of serpentine channel in heat exchangers, heat sinks, piping system, solar receiver and gas turbine blades. Originality/value The evolution mechanism of the vortices in the turning region under different gap clearance was analyzed, and thermal enhancement characteristics were predicted innovatively using topological analysis method.

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