- Analytical–Numerical Solutions for Conjugated Heat Transfer in Multistream Microsystems

2016 ◽  
pp. 368-387 ◽  
Keyword(s):  
Heat Transfer ◽  
Numerical Solutions ◽  
Conjugated Heat Transfer

A Numerical and Experimental Investigation of Turbulent Heat Transport Downstream From an Abrupt Pipe Expansion

1983 ◽  
Vol 105 (4) ◽  
pp. 862-869 ◽  
Author(s):  
R. S. Amano ◽  
M. K. Jensen ◽  
P. Goel
Keyword(s):  
Heat Transfer ◽  
Numerical Solutions ◽  
Numerical Study ◽  
Separated Flow ◽  
Flow Region ◽  
Reynolds Numbers ◽  
Turbulent Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Pipe Expansion

An experimental and numerical study is reported on heat transfer in the separated flow region created by an abrupt circular pipe expansion. Heat transfer coefficients were measured along the pipe wall downstream from an expansion for three different expansion ratios of d/D = 0.195, 0.391, and 0.586 for Reynolds numbers ranging from 104 to 1.5 × 105. The results are compared with the numerical solutions obtained with the k ∼ ε turbulence model. In this computation a new finite difference scheme is developed which shows several advantages over the ordinary hybrid scheme. The study also covers the derivation of a new wall function model. Generally good agreement between the measured and the computed results is shown.

Conjugated Heat Transfer in Skirt Hot Box in Pressure Vessels

2006 ◽  
Author(s):  
Hossein Shokouhmand ◽  
Manoochehr Bozorgmehrian
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Temperature Gradient ◽  
Thermal Stresses ◽  
Weld Line ◽  
Pressure Vessels ◽  
Conductive Heat ◽  
Air Pocket ◽  
Cyclic Operation ◽  
Conjugated Heat Transfer

Pressure vessels are common equipment in oil, gas and petrochemical industries. In a hot containing fluid vessel, excessive temperature gradient at junction of skirt to head (weld line), can cause unpredicted high thermal stresses; Thereby fracture of the vessel may occur as a result of cyclic operation. Providing a hot box (air pocket) in crotch space is a economical, applicable and easy mounted method in order to reduce the intensity of thermal stresses. Natural convection due to temperature difference between the wall of pocket, will absorb heat near the hot wall (head of the vessel) and release that near the cold wall (skirt of the vessel), then the skirt wall conducts heat to the earth as a fin. This conjugated heat transfer removes the temperature gradient boundary at welded junction. This phenomena will lead the temperature gradient on the weld line from a sudden to smooth behavior, thereby the skirt-head junction, that is a critical region, could be protected from excessive thermal stresses. In this paper the profit of hot box and conjugated heat transfer in cavity has been demonstrated experimentally. As a result it is shown that the conductive heat transfer through the skirt (which acts as a fin) ensures the continuation of natural convection in the box. Also the governing equations has been solved numerically and compared with experimental results.

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