Heat transfer with dimple/protrusion arrays in a rectangular duct with a low Reynolds number range

2008 ◽  
Vol 29 (4) ◽  
pp. 916-926 ◽  
Author(s):  
Sang Dong Hwang ◽  
Hyun Goo Kwon ◽  
Hyung Hee Cho
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Low Reynolds Number ◽  
Rectangular Duct ◽  
Number Range ◽  
Reynolds Number Range ◽  
Low Reynolds

Numerical Investigation of Micro-Channeled Louver Fin Aluminum Heat Exchangers at Low Reynolds Number

2016 ◽  
Author(s):  
Pradeep Shinde ◽  
Mirko Schäfer ◽  
Cheng-Xian Lin
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Low Reynolds Number ◽  
Poor Performance ◽  
Geometrical Parameters ◽  
Number Range ◽  
Reynolds Number Range ◽  
Low Reynolds

Extensive studies are being carried out by several researchers on the performance prediction of aluminum heat exchangers with different fin and tube geometrical configurations mostly for Reynolds number higher than 100. In the present study, the air-side heat transfer and pressure drop characteristics of the louvered fin micro-channeled, Aluminum heat exchangers are systematically analyzed by a 3D numerical simulation for very low Reynolds number from 25 to 200. Three different heat exchanger geometries obtained for the experimental investigation purposes with constant fin pitch (14 fins per inch) but varied fin geometrical parameters (fin height, fin thickness, louver pitch, louver angle, louver length and flow depth) are numerically investigated. The performance of the heat exchangers is predicted by calculating Colburn j factor and Fanning friction f factor. The effect of fin geometrical parameters on the heat exchanger performance at the Reynolds number range specified is evaluated. The air-side performance of the studied heat exchangers for the specified Reynolds number range is compared with experimental heat exchanger performance data available in the open literature and a good agreement is observed. The present results show that at the studied range of Reynolds number the flow through the heat exchanger is fin directed rather than the louver directed and therefore the heat exchanger shows poor performance. The effect of geometrical parameters on the average heat transfer coefficient is computed and design curves are obtained which can be used to predict the heat transfer performance for a given geometry.

Reynolds Number Effect on Regenerative Pump Performance in Low Reynolds Number Range

2008 ◽  
Vol 1 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Hironori Horiguchi ◽  
Daisuke Yumiba ◽  
Yoshinobu Tsujimoto ◽  
Masaaki Sakagami ◽  
Shigeo Tanaka
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Number Range ◽  
Pump Performance ◽  
Reynolds Number Effect ◽  
Reynolds Number Range ◽  
Low Reynolds

Passive Control and Enhancement of Low Reynolds Number Slot Jets Through the Use of Tabs and Chevrons

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Andrew Sexton ◽  
Jeff Punch ◽  
Jason Stafford ◽  
Nicholas Jeffers
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Integrated Circuits ◽  
Passive Control ◽  
Low Reynolds Number ◽  
Hydraulic Diameter ◽  
Stagnation Region ◽  
Number Range ◽  
Low Reynolds

Liquid microjets are emerging as candidate primary or secondary heat exchangers for the thermal management of next generation photonic integrated circuits (PICs). However, the thermal and hydrodynamic behavior of confined, low Reynolds number liquid slot jets is not yet comprehensively understood. This investigation experimentally examined jet outlet modifications—in the form of tabs and chevrons—as techniques for passive control and enhancement of single-phase convective heat transfer. The investigation was carried out for slot jets in the laminar flow regime, with a Reynolds number range, based on the slot jet hydraulic diameter, of 100–500. A slot jet with an aspect ratio of 4 and a fixed confinement height to hydraulic diameter ratio (H/Dh) of 1 was considered. The local surface heat transfer and velocity field characteristics were measured using infrared (IR) thermography and particle image velocimetry (PIV) techniques. It was found that increases in area-averaged Nusselt number of up to 29% compared to the baseline case could be achieved without incurring additional hydrodynamic losses. It was also determined that the location and magnitude of Nusselt number and velocity peaks within the slot jet stagnation region could be passively controlled and enhanced through the application of outlet tabs of varying geometries and locations.

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