Laminar flow and heat transfer in a periodic trapezoidal channel with semi-circular cross-section

2007 ◽  
Vol 50 (17-18) ◽  
pp. 3471-3480 ◽  
Author(s):  
Paul. E. Geyer ◽  
David F. Fletcher ◽  
Brian S. Haynes
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Cross Section ◽  
Circular Cross Section ◽  
Trapezoidal Channel ◽  
Flow And Heat Transfer

Hot-Wire Measurements of Turbulence Correlations in a Triangular Duct

1962 ◽  
Vol 29 (4) ◽  
pp. 609-614 ◽  
Author(s):  
C. J. Cremers ◽  
E. R. G. Eckert
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Cross Section ◽  
Circular Tube ◽  
Turbulent Transport ◽  
Circular Cross Section ◽  
Hot Wire ◽  
Round Tube ◽  
Flow Through ◽  
Hot Wires

Previous studies by flow visualization have indicated that the flow through a duct of triangular cross section is in its characteristics quite different from flow through a duct with circular cross section. They revealed among others that purely laminar flow exists in the corners of the duct even though the bulk of the fluid moves in turbulent motion. Heat-transfer measurements in such a duct appear to indicate that the turbulent transport in the direction of the height of the duct is considerably smaller than expected from circular tube measurements. The present paper reports the measurements of turbulent correlations for turbulent flow through such a duct. These measurements have been made with hot wires of very small dimensions. They again reveal the existence of a laminar corner region. In the bulk of the fluid, the differences of the correlations to those in a round tube turned out to be smaller than originally suspected.

scholarly journals Experimental Study on Liquid Flow and Heat Transfer in Rough Microchannels

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Xuan Zhang ◽  
Taocheng Zhao ◽  
Suchen Wu ◽  
Feng Yao
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Cross Section ◽  
Liquid Flow ◽  
Flow And Heat Transfer ◽  
Section Shape ◽  
Poiseuille Number

Although roughness is negligible for laminar flow through tubes in classic fluid mechanics, the surface roughness may play an important role in microscale fluid flow due to the large ratio of surface area to volume. To further verify the influence of rough surfaces on microscale liquid flow and heat transfer, a performance test system of heat transfer and liquid flow was designed and built, and a series of experimental examinations are conducted, in which the microchannel material is stainless steel and the working medium is methanol. The results indicate that the surface roughness plays a significant role in the process of laminar flow and heat transfer in microchannels. In microchannels with roughness characteristics, the Poiseuille number of liquid laminar flow relies not only on the cross section shape of the rough microchannels but also on the Reynolds number of liquid flow. The Poiseuille number of liquid laminar flow in rough microchannels increases with increasing Reynolds number. In addition, the Nusselt number of liquid laminar heat transfer is related not only to the cross section shape of a rough microchannel but also to the Reynolds number of liquid flow, and the Nusselt number increases with increasing Reynolds number.

Fluid Flow and Heat Transfer Characteristics in the Entrance Regions of Circular Pipes

1985 ◽  
Author(s):  
S. Lloyd ◽  
A. Brown
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Circular Cross Section ◽  
Flow Visualisation ◽  
Pressure Measurements ◽  
Hot Wire ◽  
Heat Transfer Characteristics ◽  
Number Range ◽  
Flow And Heat Transfer ◽  
Circular Pipes

This paper describes the results of an experimental investigation into the velocity and turbulence fields and to a lesser extent the heat transfer in the entrance regions of short, circular cross-section pipes with length to diameter ratios up to 20 over the Reynolds number range from 35,000 to 170,000. The velocity and turbulence fields were measured by hot-wire anemometers backed up with pressure measurements and flow visualisation and the heat transfer by heat flux meters.

Laminar Flow and Heat Transfer in Spiral Ducts of Rectangular Cross Section

2004 ◽  
Author(s):  
Michael W. Egner ◽  
Louis C. Burmeister
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Radius Of Curvature ◽  
Dean Number ◽  
Flow And Heat Transfer ◽  
Aspect Ratios ◽  
Small Pitch

Laminar flow and heat transfer in three-dimensional spiral ducts of rectangular cross section with aspect ratios of 1, 4, and 8 were determined with the aide of the FLUENT computational fluid dynamics program. Peripherally-averaged coefficients of friction and Nusselt numbers are presented as a function of distance from the inlet and of the Dean number. Fully-developed values of friction coefficient and Nusselt number for a constant-radius-of-curvature duct, either toroidal or helical with small pitch, can be used to predict those quantities for the spiral duct in post-entry regions. These results are applicable to spiral-plate heat exchangers.

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