scholarly journals Heat Transfer Performance of a Fin with Two Fences and Tube Heat Exchanger. Study in the Low Reynolds Number Range.

2000 ◽  
Vol 66 (647) ◽  
pp. 1796-1803
Author(s):  
Hajime ONISHI ◽  
Kyoji INAOKA ◽  
Kenjiro SUZUKI
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Heat Transfer Performance ◽  
Low Reynolds Number ◽  
Transfer Performance ◽  
Number Range ◽  
Tube Heat Exchanger ◽  
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.

scholarly journals Heat transfer performance and friction factor of various nanofluids in a double-tube counter flow heat exchanger

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3601-3612
Author(s):  
Dan Zheng ◽  
Jin Wang ◽  
Yu Pang ◽  
Zhanxiu Chen ◽  
Bengt Sunden
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Friction Factor ◽  
Flow Resistance ◽  
Heat Transfer Performance ◽  
Weight Fraction ◽  
Transfer Performance ◽  
Tube Heat Exchanger ◽  
High Heat Transfer

Experimental research was conducted to reveal the effects of nanofluids on heat transfer performance in a double-tube heat exchanger. With nanoparticle weight fraction of 0.5-2.0% and Reynolds number of 4500-14500, the flow resistance and heat transfer were analyzed by using six nanofluids, i.e., CuO-water, Al2O3-water, Fe3O4-water, ZnO-water, SiC-water, SiO2-water nanofluids. Results show that SiC-water nanofluid with a weight concentration of 1.5% provides the best improvement of heat transfer performance. 1.0% CuO-water and 0.5% SiO2-water nanofluids have lower friction factors in the range of Reynolds number from 4500-14500 compared to the other nanofluids. Based on test results of heat transfer performance and flow resistance, the 1.0% CuO-water nanofluid shows a great advantage due to a relatively high heat transfer performance and a low friction factor. Finally, empirical formulae of Nusselt numbers for various nanofluids were established based on experimental data tested in the double-tube heat exchanger.

Wavy-Channel for Microscale Heat Transfer in Macro Geometries

2017 ◽  
Author(s):  
Kai Xian Cheng ◽  
Zi Hao Foo ◽  
Kim Tiow Ooi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Performance Index ◽  
Heat Transfer Performance ◽  
Cnc Machining ◽  
Hydrodynamic Performance ◽  
Working Fluid ◽  
Transfer Performance ◽  
Number Range ◽  
Reynolds Number Range

Microscale heat and fluid flow in macro geometries have been made practical in terms of cost and fabrication, by superimposing two macro geometries which are fabricated using readily-available CNC machining methods. Wavy-profile has been proposed to enhance heat transfer performance in the microchannel owing to the simplicity of geometry and feasibility to be fabricated using simple turning process. Experimental studies were conducted on single-phase, forced convective heat transfer using water as the working fluid for the Reynolds number range of 1300 to 4600, for a constant heat flux of 53.0 W/cm2. Three sinusoidal waves with different wavelength and same amplitude are studied to examine the effect of the total number of waves on the heat transfer and hydrodynamic performance within constant microchannel length. The maximum performance index, which evaluates heat transfer performance per unit pumping power, is 1.39, achieved by wavy profile with the shortest wavelength at Reynolds number of 2800. The performance index for all the enhanced microchannels peaks at the Reynolds number range of 2500 to 2800. Beyond that, the performance index is not a strong function of the wavelength. At lower Reynolds numbers, profile with the shortest wavelength achieves substantially higher performance indices, as the increment in pressure drop is accompanied by a comparable increment in heat transfer. Future work includes the introduction of correlations for the implementation of such geometries in industrial heat exchangers.

Airside Performance of Wavy Fin-and-Tube Heat Exchangers: Data With Larger Diameter Tube

2010 ◽  
Author(s):  
Huau Pao Lo ◽  
Chinghua Hung ◽  
Chi-Chuan Wang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Low Reynolds Number ◽  
Transfer Performance ◽  
Frictional Performance ◽  
Low Reynolds

This study examines the airside fin-and-tube heat exchangers having a larger diameter tube Dc = 16.59 mm) with the tube row ranging from 1 to 16. It is found that the effect of tube row on the heat transfer performance is quite significant, and the heat transfer performance deteriorates with the rise of tube row. The performance deteriorates with the rise of tube row. The performance drop is especially pronounced at the low Reynolds number region. Actually more than 85% drop of heat transfer performance is seen for Fp ∼ 1.7 mm as the row number is increased from 1 to 16. Upon the influence of tube row on the frictional performance, an unexpected row dependence of the friction factor is encountered. The effect of fin pitch on the airside performance is comparatively small for N = 1 or N = 2. However, a notable drop of heat transfer performance is seen when the number of tube row is increased, and normally higher heat transfer and frictional performance is associated with that of the larger fin pitch.

A Numerical Study of the Plate Heat Exchanger With Compound Corrugations in the Condition of Low Reynolds Number and High Prandtl Number

2010 ◽  
Author(s):  
Xing Cao ◽  
Wenjing Du ◽  
Guanmin Zhang ◽  
Lin Cheng
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Flow Resistance ◽  
Heat Transfer Performance ◽  
Low Reynolds Number ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
High Prandtl Number ◽  
Low Reynolds

In general the conventional plate heat exchanger has good heat transfer performance on the one hand and high pressure drop on the other hand. In order to deal with this dilemma, a novel plate heat exchanger with compound corrugations is proposed in this paper. Comparisons with the traditional plate heat exchanger indicate that the new heat exchanger can reduce flow resistance and simultaneously improve its heat transfer performance. The heat-transfer oil with a relatively high dynamic viscosity is selected as the working fluid. The performance in the newly-proposed plate heat exchanger with compound corrugations in the condition of low Reynolds number and high Prandtl number is numerically investigated. In the process of numerical simulations, variations are made on one geometric parameter of the plates and keep invariant for the others. Through comparisons on the j-factor, the friction factor and their ratio j/f for various plate geometries, the influence of geometry parameters on heat transfer performance, flow resistance characteristics and comprehensive heat exchanger performance is thoroughly examined. Based on numerical results, the geometric parameters which have significant impact on heat transfer and flow resistance of the proposed plate heat exchanger are determined. And the Nusselt number and friction factor correlations of the plate heat exchanger with compound corrugations are obtained, which are applicable for the laminar flow mode when the working fluid is with low Reynolds number and high Prandtl number.

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