Local heat transfer on the entrance segment of a tube with a sharp inlet edge. 2. Correction for the entrance segment under turbulent boundary layer conditions

1993 ◽  
Vol 65 (2) ◽  
pp. 722-725 ◽  
Author(s):  
V. M. Legkii ◽  
V. A. Rogachev
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Local Heat Transfer ◽  
Local Heat

Heat Transfer in the Oscillating Turbulent Boundary Layer

1969 ◽  
Vol 91 (4) ◽  
pp. 239-244 ◽  
Author(s):  
James A. Miller
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Mean Velocity ◽  
Heat Transfer Coefficients ◽  
Nusselt Numbers ◽  
Local Coefficients

Measurements of local heat-transfer coefficients in the fully established oscillating turbulent boundary layer over a flat plate are reported. In the range of frequencies from 0.1 to 200 cps and amplitudes from 8 to 92 percent of the freestream mean velocity, increases in local Nusselt numbers of 3 to 5 percent were found. It is concluded that substantial increases in local coefficients, sometimes reported in oscillating flows of low standing wave ratio, may be traced to reduced transition Reynolds numbers.

scholarly journals Heat Transfer in the Oscillating Turbulent Boundary Layer

1969 ◽  
Author(s):  
J. A. Miller
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Mean Velocity ◽  
Heat Transfer Coefficients ◽  
Nusselt Numbers ◽  
Local Coefficients

Measurements of local heat transfer coefficients in the fully established oscillating turbulent boundary layer over a flat plate are reported. In the range of frequencies from 0.1 to 200 cps and amplitudes from 8 to 92 percent of the freestream mean velocity increases in local Nusselt numbers of 3 to 5 percent were found. It is concluded that substantial increases in local coefficients sometimes reported in oscillating flows of low standing wave ratio may be traced to reduced transition Reynolds numbers.

Velocity, Temperature, and Heat-Transfer Measurements in a Turbulent Boundary Layer Downstream of a Stepwise Discontinuity in Wall Temperature

1957 ◽  
Vol 24 (1) ◽  
pp. 2-8
Author(s):  
D. S. Johnson
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Free Stream ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Velocity Fields ◽  
Temperature Fields ◽  
Mean Velocity ◽  
The Mean

Abstract Results are presented of an experimental investigation of the concomitant thermal and velocity fields occurring when there is a small stepwise discontinuity in the temperature of the wall on which a zero-pressure-gradient, low-speed, turbulent boundary layer has formed. The mean velocity and temperature fields have been measured and local heat-transfer-coefficient values in the stream-wise direction have been obtained in the region where the thermal boundary layer has not yet reached the free stream. No over-all similarity between the thermal and velocity fields was found.

Effect of Turbulence on the Heat Transfer in a Laminar and Turbulent Boundary Layer Over a Gas Turbine Blade

1982 ◽  
Author(s):  
V. Krishnamoorthy
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Transfer Coefficient ◽  
Turbulent Boundary Layer ◽  
Transfer Coefficient ◽  
Turbine Blade ◽  
Turbulence Intensity ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Turbulence Generator

This paper describes the results of the systematic investigations undertaken to identify the effect of free stream turbulence intensity on the local heat transfer coefficient distribution in the laminar and turbulent boundary layer present over a turbine blade profile in a two-dimensional cascade. The local heat-transfer coefficient was measured under constant heat flux boundary condition. Experiments were conducted at exit Reynolds numbers (based on blade chord) Rc = 2, 4.5 × 105 and at turbulence intensities εi up to 21.3 percent. A novel type of turbulence generator was used, with which it was possible to vary the turbulence intensity in the plane of the cascade without changing the distance between the turbulence generator and the cascade and without significantly varying the integral length scale of the turbulence.

DESIGN AND STUDY OF EXCHANGERS WITH PRESSURE GRADIENT HEAT INTENSIFIERS

2018 ◽  
Vol 8 (3) ◽  
pp. 137-144
Author(s):  
Nadezhda P. PETROVA ◽  
Anna A. TSYNAEVA
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Gradient ◽  
Heat Exchangers ◽  
Numerical Study ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Longitudinal Pressure Gradient ◽  
Heat Transfer Coeffi

This paper is presented the numerical study of local heat transfer in the turbulent boundary layer with longitudinal pressure gradient. The study is based to free software with open source code (Salome and Code_Saturne) has been based by RANS approach and empirical models of turbulence. Validation of mathematical models and software is based by collation numerical results with the results of experimental study of fl ow characteristics in a turbulent boundary layer of longitudinal pressure gradient and high turbulence intensity (Epik E. Ya., NASc of Ukraine). The validation had a high qualitative coincidence of the fl ow characteristics determined as a result of the simulation with experimental data. We designed two constructive schemes of heat exchangers for air. This study presents a calculation plan for these heat exchangers. Results of the study are showed that the use of gradient heat exchange intensifi ers leads to an increase in the heat transfer coeffi cient from air to 17 %.

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