scholarly journals Heat-Transfer and Mixing Enhancement by Vortex Generators Used in Heat Exchanger-Reactors

2003 ◽  
Author(s):  
S. Ferrouillat ◽  
P. Tochon ◽  
C. Garnier ◽  
H. Peerhossaini
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Flow Direction ◽  
Vortex Generator ◽  
Chemical Reactor ◽  
Vortex Generators ◽  
Mixing Enhancement ◽  
Transfer Enhancement ◽  
Longitudinal Vortices

Compact heat exchangers are well known for their ability to transfer a large amount of heat while retaining low volume and weight. The purpose of this paper is to study the potential of using this device as a chemical reactor, generally called a heat exchanger-reactor (HEX reactor). Indeed, the question arises: can these geometries combine heat transfer and mixing in the same device? Such a technology would offer many potential advantages, such as better reaction control (through the thermal aspect), improved selectivity (through intensified mixing, more isothermal operation and shorter residence time, and sharper RTDs), byproduct reduction, and enhanced safety. Several geometries of compact heat exchanger based on turbulence generation are available. This paper focuses on one type: vortex generators. The main objective is to contribute to the determination of turbulent flow inside various geometries by computational fluid dynamics methods. These enhanced industrial geometries are studied in terms of their thermal-hydraulic performance and macro-/micro-mixing ability. The longitudinal vortices they generate in a channel flow turn the flow perpendicular to the main flow direction and enhance mixing between the fluid close to the fin and that in the middle of the channel. Two kinds of vortex generators are considered: a delta winglet pair and a rectangular winglet pair. For both, good agreement is obtained between numerical results and data in the literature. The vortex generator concept is found to be very efficient in terms of heat-transfer enhancement and macro-mixing. Nevertheless, the micro-mixing level is poor due to strong inhomogeneities: the vortex generator must be used as a heat-transfer enhancement device or as a static mixer for macro- and meso-mixing.

A Critical Review of the Prominent Method of Heat Transfer Enhancement for the Fin-and-Tube Heat Exchanger by Interrupted Fin Surface: The Vortex Generators Approach

2018 ◽  
Vol 26 (03) ◽  
pp. 1830001 ◽  
Author(s):  
Nares Chimres ◽  
Somchai Wongwises
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Flow Characteristics ◽  
Vortex Generator ◽  
Vortex Generators ◽  
Experimental Investigations ◽  
Transfer Enhancement ◽  
Tube Heat Exchanger ◽  
Performance Indexes

The performance of heat exchangers impacts industry investment, energy consumption, and pollution because the heat exchanger has been used in many industries. The use of vortex generators on the fin is the prominent method of heat transfer enhancement because the performance indexes of fins with vortex generators are greater than those of the fins without vortex generators. However, this method faces obstacles because the concepts and design instructions are still obscure. Therefore, this paper provides a summary of the publications about the use of vortex generators. The publications on the effects of traditional and alternative vortex generators that are combined with plain, wavy, and louver fins are summarized. The aim of this paper is to aggregate the publications concerned with the thermal performance and flow characteristics of the fin-and-tube heat exchanger with vortex generator using numerical and experimental investigations as the guideline for future studies.

Heat transfer enhancement for fin-tube heat exchanger using vortex generators

2002 ◽  
Vol 16 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Seong-Yeon Yoo ◽  
Dong-Seong Park ◽  
Min-Ho Chung ◽  
Sang-Yun Lee
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Vortex Generators ◽  
Transfer Enhancement ◽  
Tube Heat Exchanger ◽  
Fin Tube

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 of Heat Transfer Enhancement on a Small Scale Vortex Generator

2009 ◽  
Author(s):  
Jiansheng Wang ◽  
Zhiqin Yang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Flow Structure ◽  
Rectangular Channel ◽  
Vortex Generator ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Vortex Generators ◽  
Small Scale ◽  
Transfer Enhancement

The heat transfer characteristic and flow structure of fluid in the rectangular channel with different height vortex generators in small scale are investigated with numerical simulation. Meantime, the properties of heat transfer and flow of fluid in the rectangular channel are compared with the channel which located small scale vortex generator. The variation law of local heat transfer and flow structure in channel is obtained. The mechanism of heat transfer enhancement of small scale vortex generators is discussed in detail. It is found that the influence of vortex generator on heat transfer is not in proportion to the size of vortex generator. What is more, turbulent flow structure near the wall, which influences the temperature distribution near the wall, induces the variety of local heat transfer. The fluid movement towards to the wall causes the heat transfer enhanced. On the contrary, the fluid movement away from the wall decreases the local heat transfer.

Numerical Investigation of Heat Transfer Enhancement Using Hybrid Vortex Generator Arrays in Fin-and-Tube Heat Exchangers

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Shubham Agarwal ◽  
R. P. Sharma
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Numerical Study ◽  
Vortex Generator ◽  
Roll Angle ◽  
Transfer Enhancement ◽  
Maximum Heat ◽  
Hybrid Configuration

This is a novel study for assessing the heat transfer enhancement in a multi-row inline-tube heat exchanger using hybrid vortex generator (VG) arrays, i.e., rectangular winglet pairs (RWPs) with different geometrical configurations installed in coherence for enhanced heat transfer. The three-dimensional numerical study uses a full scale seven-tube inline heat exchanger model. The effect of roll of rectangular winglet VG on heat transfer enhancement is analyzed and optimized roll angle is determined for maximum heat transfer enhancement. Four different configurations are analyzed and compared in this regard: (a) single RWP (no roll); (b) 3RWP-inline array(alternating tube row with no roll of VGs); (c) single RWP (with optimized roll angle VGs); and (d) 3RWP-inline array(alternating tube row with all VGs having optimized roll angle). It was found that the inward roll of VGs increased the heat transfer from the immediately downstream tube but reduced heat transfer enhancement capability of other VG pairs downstream. Further, four different hybrid configurations of VGs were analyzed and the optimum configuration was obtained. For the optimized hybrid configuration at Re = 670, RWP with optimized roll angle increased heat transfer by 17.5% from the tube it was installed on and by 42% from the immediately downstream tube. Increase in j/ƒ of 36.7% is obtained by use of hybrid VGs in the optimized hybrid configuration. The deductions from the current study are supposed to well enhance the performance of heat exchangers with different design configurations.

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