Investigation of Vortex Generator Enhanced Double-Fin and Tube Heat Exchanger

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Shobhana Singh ◽  
Kim Sørensen ◽  
Thomas Condra
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Conjugate Heat Transfer ◽  
Waste Heat ◽  
Vortex Generator ◽  
Manufacturing Cost ◽  
Number Range ◽  
Tube Heat Exchanger

In the present work, a numerical analysis of conjugate heat transfer and fluid flow in vortex generator (VG) enhanced double-fin and tube heat exchanger is carried out. The enhanced design aims to improve the heat transfer performance of a conventional double-fin and tube heat exchanger for waste heat recovery applications. A three-dimensional (3D) numerical model is developed using ANSYS cfx to simulate fluid flow and conjugate heat transfer process. Numerical simulations with rectangular winglet vortex generators (RWVGs) at five different angles of attack (−20deg≤α≤20deg) are performed for the Reynolds number range of 5000≤Re≤11,000. Salient performance characteristics are analyzed in addition to the temperature distribution and flow fields. Based on the numerical results, it is concluded that the overall performance of the double-fin and tube heat exchanger can be improved by 27–91% by employing RWVGs at α=−20deg for the range of Reynolds number investigated. The study provides useful design information and necessary performance data that can be adopted for the design development of the heat exchanger at a lower manufacturing cost.

Heat Transfer Characterization of a Finned-Tube Heat Exchanger (With and Without Condensation)

1990 ◽  
Vol 112 (1) ◽  
pp. 64-70 ◽  
Author(s):  
S. A. Idem ◽  
A. M. Jacobi ◽  
V. W. Goldschmidt
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Factor Versus ◽  
Finned Tube ◽  
Transfer Coefficients ◽  
Number Range ◽  
Tube Heat Exchanger ◽  
Pressure Losses ◽  
Finned Tube Heat Exchanger

The effects upon the performance of an air-to-water copper finned-tube crossflow heat exchanger due to condensation on the outer surface are considered. A four-tube, two-pass heat exchanger was tested over a Reynolds number range (based on hydraulic diameter) from 400 to 1500. The coil was operated both in overall parallel and overall counterflow configurations. Convective heat and mass transfer coefficients are presented as plots of Colburn j-factor versus Reynolds number. Pressure losses are, similarly, presented as plots of the friction factor versus Reynolds number. Enhancement of sensible heat transfer due to the presence of a condensate film is also considered.

Air-Side Heat-Transfer Enhancement by a New Winglet-Type Vortex Generator Array in a Plain-Fin Round-Tube Heat Exchanger

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
J. He ◽  
L. Liu ◽  
A. M. Jacobi
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Vortex Generator ◽  
Round Tube ◽  
Number Range ◽  
Tube Heat Exchanger ◽  
Large Pair ◽  
Goodness Factor ◽  
The Impact ◽  
Heat Transfer Improvement

The impact of a vortex-generation technique for air-side heat-transfer improvement is experimentally investigated through full-scale wind-tunnel testing of a plain-fin round-tube heat exchanger under dry-surface conditions. Inspired by the formation locomotion of animals in nature, a new vortex generator (VG) array deployed in a “V” is proposed in the present work, aiming to create constructive interference between vortices. The array is composed of two delta-winglet pairs and placed at an attack angle of 10 deg or 30 deg. Its effectiveness is compared with a baseline configuration and two conventional single-pair designs placed at 30 deg, a small pair with half the area of the array and a large pair with the same area as the array. The frontal air velocity considered ranges from 2.3 m/s to 5.5 m/s, corresponding to a Reynolds number range based on the hydraulic diameter of 1400–3400. The experimental results show little impact of the 10 deg array and a moderate heat-transfer improvement of up to 32% for the small pair, both introducing additional pressure loss of approximately 20–40%. For the 30 deg array and the large pair, similar augmentation of 25–55% in air-side heat-transfer coefficient is obtained accompanied by average pressure drop penalties of 90% and 140%, respectively. Performance evaluation using the criteria of the modified area goodness factor and the volume goodness factor indicates the superiority of the heat exchanger enhanced by the 30 deg array among all the investigated VGs. The VG array is found more effective at comparatively low Reynolds numbers, representative of many heating, ventilation, air-conditioning, and refrigeration applications and compact heat-exchanger designs.

Air-Side Heat Transfer Enhancement by a Novel Winglet-Type Vortex Generator Array in a Round-Tube Plain-Fin Heat Exchanger

2009 ◽  
Author(s):  
Jing He ◽  
Liping Liu ◽  
Anthony M. Jacobi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Vortex Generator ◽  
Attack Angle ◽  
Transfer Enhancement ◽  
Number Range ◽  
Reynolds Number Range ◽  
Goodness Factor

The impact of vortex generator (VG) arrays for air-side heat transfer enhancement is experimentally investigated by full-scale wind-tunnel testing of a plain-fin-and-tube heat exchanger. The VG array is deployed in a “V” to try to create a constructive interference between vortices. Each array is composed of two delta-winglet pairs (four VGs), and placed at an attack angle of 10° or 30°. The frontal air velocity considered is between 2.3–5.4 m/s, corresponding to a Reynolds number range based on the hydraulic diameter of 1500–3400. The thermal-hydraulic performance of the heat exchanger with and without VG enhancement is provided under dry-surface conditions. The experimental results indicate little impact at a relatively small attack angle of 10°. While for the 30° array, a 25–55% augmentation in air-side heat transfer coefficient is measured, but with a pressure drop penalty of 100%. Nevertheless, performance evaluation using the area goodness factor and the volume goodness factor both indicate the superiority of the enhanced heat exchanger by the 30° array over the entire Reynolds number range. The proposed array is found more effective at comparatively low Reynolds numbers, representative of many HVAC&R applications and compact heat exchanger designs.

Bayonet Tube Heat Exchanger

1997 ◽  
Vol 50 (8) ◽  
pp. 445-473 ◽  
Author(s):  
G. S. H. Lock ◽  
Harpal Minhas
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Waste Heat ◽  
Thermal Studies ◽  
Experimental Studies ◽  
Return Flow ◽  
Tube Heat Exchanger ◽  
Numerical Predictions

This review article provides an overview and assessment of the bayonet tube heat exchanger in its concentric tube configuration. The article begins with a brief historical sketch of its use in three main contexts: in the process industries, especially in waste heat recovery; in geotechnical engineering, in permafrost stabilization; and in medicine, especially in cryosurgery. A conceptual outline describing the main heat transfer features of the device in counterflow, parallel flow, and cross flow situations follows. Particular attention is paid to the implications of thermal coupling between the inner tube flow, the annular (return) flow and the external fluid flow. The main text is divided into two parts: Experimental studies and Theoretical studies. Each of these is subdivided into two complementary sections: hydraulic studies, in which the emphasis is placed on fluid flow characteristics, especially in the U-bend at the end of the tube; and thermal studies, emphasizing the convective heat transfer characteristics. Each subsection is further divided to permit separate discussion of laminar, transitional and turbulent flow under steady, single-phase conditions. Experimental data are systematically compared with numerical predictions to provide a comprehensive survey of the effect of the independent variables (flow rate, tube geometry, and fluid properties) on the dependent variables (pressure drop, heat transfer rate). Experimental and numerical data are combined to develop empirical correlations for pressure drop and heat transfer. The final section examines the above findings to uncover the limitations of our current knowledge and thereby suggest profitable avenues for future research. There are 47 references listed at the end of the article.

scholarly journals Review on Heat Transfer Enhancement by Louvered Fin

2021 ◽  
Vol 6 (1) ◽  
pp. 60-80
Author(s):  
Samsul Islam ◽  
Md. Shariful Islam ◽  
Mohammad Zoynal Abedin
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Vortex Generator ◽  
Transfer Enhancement ◽  
Maximum Heat ◽  
Louvered Fin ◽  
Heat Transfer Improvement ◽  
Better Than

The heat transfer enhancement is recycled in many engineering uses such as heat exchangers, refrigeration and air conditioning structures, chemical apparatuses, and automobile radiators. Hence many enhancing extended fin patterns are developed and used. In multi louvered fin, in this segment for multi-row fin and tube heat exchanger, an increase in heat transfer enhancement is found 58% for ReH = 350. When the Reynolds number is 1075, the temperature gradient is more distinct for greater louver angle that is the higher heat transfer enhanced for large louver angle. For variable louver angle heat exchanger, the maximum heat transfer improvement achieved by 118% Reynolds number at 1075. In the vortex generator for the delta winglet vortex generator, the extreme enhancement of heat transfer increased to 16% compared to the baseline geometry (at ReDh = 600). For a compact louvered heat exchanger, the results showed that a regular arrangement of louvered fins gives a 9.3% heat transfer improvement. In multi-region louver fins and flat tubes heat exchanger, the louver fin with 4 regions and the louver fin with 6 regions are far better than the conventional fin in overall performance. At the same time, the louver fin with 6 regions is also better than the louver fin with 4-region. The available work is in experimental form as well as numerical form performed by computational fluid dynamics.

Numerical Investigation on Heat Transfer of Al2O3/Water Nanofluid in a Shell and Tube Heat Exchanger

2014 ◽  
Vol 591 ◽  
pp. 3-6
Author(s):  
M. Raja ◽  
R. Vijayan ◽  
R. Vivekananthan ◽  
M.A. Vadivelu
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Numerical Investigation ◽  
Volume Concentration ◽  
Heat Transfer Characteristics ◽  
Tube Heat Exchanger ◽  
Transfer Characteristics ◽  
Shell And Tube ◽  
Suspended Nanoparticles

In the present work, the effect of nanofluid in a shell and tube heat exchanger was studied numerically. The effects of Reynolds number, volume concentration of suspended nanoparticles on the heat transfer characteristics were investigated using CFD software. Finally, the effect of the nanofluid on Shell and tube heat exchanger performance was studied and compared to that of a conventional fluid (i.e., water).

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