scholarly journals Effect of Streamline Curvature on Heat Transfer in Turbulent Flow over Backward Facing Step

2019 ◽  
Vol 577 ◽  
pp. 012121
Author(s):  
P Sajesh ◽  
J S Jayakumar
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Backward Facing Step ◽  
Streamline Curvature

Local Heat Transfer Measurements in Turbulent Flow Around a 180-deg Pipe Bend

1987 ◽  
Vol 109 (1) ◽  
pp. 43-48 ◽  
Author(s):  
J. W. Baughn ◽  
H. Iacovides ◽  
D. C. Jackson ◽  
B. E. Launder
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Turbulent Flow ◽  
Transfer Coefficient ◽  
Secondary Flow ◽  
Local Heat Transfer ◽  
Reynolds Numbers ◽  
Local Heat ◽  
Pipe Bend ◽  
Streamline Curvature

The paper reports extensive connective heat transfer data for turbulent flow of air around a U-bend with a ratio of bend radius:pipe diameter of 3.375:1. Experiments cover Reynolds numbers from 2 × 104 to 1.1 × 105. Measurements of local heat transfer coefficient are made at six stations and at five circumferential positions at each station. At Re = 6 × 104 a detailed mapping of the temperature field within the air is made at the same stations. The experiment duplicates the flow configuration for which Azzola and Humphrey [3] have recently reported laser-Doppler measurements of the mean and turbulent velocity field. The measurements show a strong augmentation of heat transfer coefficient on the outside of the bend and relatively low levels on the inside associated with the combined effects of secondary flow and the amplification/suppression of turbulent mixing by streamline curvature. The peak level of Nu occurs halfway around the bend at which position the heat transfer coefficient on the outside is about three times that on the inside. Another feature of interest is that a strongly nonuniform Nu persists six diameters downstream of the bend even though secondary flow and streamline curvature are negligible there. At the entry to the bend there are signs of partial laminarization on the inside of the bend, an effect that is more pronounced at lower Reynolds numbers.

Numerical Simulation of a Turbulent Flow Over a Backward Facing Step With Heated Wall: Effect of Pulsating Velocity and Oscillating Wall

2012 ◽  
Vol 4 (4) ◽  
Author(s):  
A. K. Pozarlik ◽  
J. B. W. Kok
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Steady State ◽  
Turbulent Flow ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Excitation Frequency ◽  
Heated Wall ◽  
Backward Facing Step ◽  
Inlet Flow

An accurate prediction of the flow and the thermal boundary layer is required to properly simulate gas to wall heat transfer in a turbulent flow. This is studied with a view to application to gas turbine combustors. A typical gas turbine combustion chamber flow presents similarities with the well-studied case of turbulent flow over a backward facing step, especially in the near-wall regions where the heat transfer phenomena take place. However, the combustion flow in a gas turbine engine is often of a dynamic nature and enclosed by a vibrating liner. Therefore apart from steady state situations, cases with an oscillatory inlet flow and vibrating walls are investigated. Results of steady state and transient calculations for the flow field, friction coefficient, and heat transfer coefficient, with the use of various turbulence models, are compared with literature data. It has been observed that the variations in the excitation frequency of the inlet flow and wall vibrations have an influence on the instantaneous heat transfer coefficient profile. However, significant effect on the time mean value and position of the heat transfer peak is only visible for the inlet velocity profile fluctuations with frequency approximately equal to the turbulence bursting frequency.

Comparison of RANS and IDDES solutions for turbulent flow and heat transfer past a backward-facing step

2017 ◽  
Vol 54 (8) ◽  
pp. 2231-2241 ◽  
Author(s):  
E. M. Smirnov ◽  
A. A. Smirnovsky ◽  
N. A. Schur ◽  
D. K. Zaitsev ◽  
P. E. Smirnov
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Backward Facing Step ◽  
Flow And Heat Transfer

Heat Transfer in Suddenly Expanded Flow in a Channel With Porous Inserts

2000 ◽  
Author(s):  
Francisco D. Rocamora ◽  
Marcelo J. S. de Lemos
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Flow Pattern ◽  
Numerical Results ◽  
Lower Wall ◽  
Heat Transfer Characteristics ◽  
Backward Facing Step ◽  
Porous Insert ◽  
Transfer Characteristics ◽  
Flow Past

Abstract This paper presents numerical results for laminar heat transfer and turbulent flow past a backward-facing step channel with and without a porous insert. The effects of thickness and permeability of the inserts on flow pattern and heat transfer features are assessed. It is found that for some combinations of thickness and permeability, the recirculating bubble right after the step is completely suppressed, improving the heat transfer characteristics for the lower wall.

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