Optimization of the Angle of Attack of Delta-Winglet Vortex Generators Over a Bank of Elliptical-Tubes Heat Exchanger

2013 ◽  
Author(s):  
K. Godazandeh ◽  
M. H. Ansari ◽  
B. Godazandeh ◽  
M. Ashjaee
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Cfd Simulation ◽  
Angle Of Attack ◽  
Vortex Generators ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Transfer Enhancement ◽  
The Impact

In order to reach a more efficient and compact heat exchanger, it is essential to optimize the design, having in mind the impact of different geometrical parameters. Many of the previously cited studies in the area of heat transfer enhancement using vortex generators were confined only to defined points in the possible design space. Thus, a multi-objective optimization study is particularly suitable in order to cover this space entirely. A CFD simulation along with Pareto method were used to simulate the air flow and heat transfer and optimize the design parameters. The angle of attack of a pair of delta-winglets mounted behind each tube is varied between β = −90° and β = +90°. Three elliptical tube rows with inline arrangements are investigated for Reynolds numbers from 500 to 1500 (based on the inlet properties). Use of delta-winglets as heat transfer enhancement elements increases the performance of elliptical-tubes heat exchanger. This enhancement is mainly due to the fact that delta-winglets increase the level of vorticity inside these devices and thus the mixing of the fluid is enhanced.

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

Parametric Study of Vortex Generator Effects in an Additive Manufactured Minichannel Heat Exchanger

2019 ◽  
Author(s):  
Hamidreza Rastan ◽  
Tim Ameel ◽  
Björn Palm
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Additive Manufacturing ◽  
Heat Exchanger ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
High Energy ◽  
Vortex Generators ◽  
Design Parameters ◽  
Minichannel Heat Exchanger

Abstract Heat exchangers with mini- and micro-channel components are capable of high energy exchange due to their incumbent large surface area to volume ratio. Concurrently, recent advances in additive manufacturing simplify the creation of metallic minichannels that incorporate turbulators for heat transfer enhancement. As part of the development of a minichannel heat exchanger with turbulators, this study analyzes the three-dimensional conjugate heat transfer and laminar flow in a minichannel heat exchanger equipped with rectangular winglet vortex generators (VGs) through numerical simulation. The minichannels have a hydraulic diameter of 2.86 mm and are assumed to be made from aluminum alloy AlSi10Mg. This material is one of the popular alloys in the additive manufacturing industry (three-dimensional (3D) printing) because of its light weight and beneficial mechanical and thermal properties. The working fluid is distilled water with temperature-dependent thermal properties. The minichannel is heated by a constant heat flux of 5 W cm−2 and the Reynolds number is varied from 230 to 950. The simulations are performed using the COMSOL® platform, which solves the governing mass, momentum, and energy equations based on the finite element method. The effect of the VG design parameters, which include VG angle of attack, height, length, thickness, longitudinal pitch, and distance from the sidewalls, is investigated. It is found that the generation of three-dimensional vortices caused by the presence of the vortex generators can notably boost the convective heat transfer, at the cost of increased pressure drop, potentially reducing the heat exchanger size for a given heat duty. A sensitivity analysis indicates that the angle of attack, VG height, VG length, and longitudinal pitch have the most significant effects on the heat transfer and flow friction characteristics. In contrast, the VG thickness and distance from the sidewalls only had minor influences on the heat exchanger performance over the studied range of design parameters.

A Numerical Study of Flow and Heat Transfer Enhancement Using an Array of Delta-Winglet Vortex Generators in a Fin-and-Tube Heat Exchanger

2006 ◽  
Vol 129 (9) ◽  
pp. 1156-1167 ◽  
Author(s):  
A. Joardar ◽  
A. M. Jacobi
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Numerical Study ◽  
Flow Behavior ◽  
Vortex Generators ◽  
Computational Domain ◽  
Transfer Enhancement ◽  
Local Flow ◽  
Tube Heat Exchanger

This work is aimed at assessing the potential of winglet-type vortex generator (VG) “arrays” for multirow inline-tube heat exchangers with an emphasis on providing fundamental understanding of the relation between local flow behavior and heat transfer enhancement mechanisms. Three different winglet configurations in common-flow-up arrangement are analyzed in the seven-row compact fin-and-tube heat exchanger: (a) single–VG pair; (b) a 3VG-inline array (alternating tube row); and (c) a 3VG-staggered array. The numerical study involves three-dimensional time-dependent modeling of unsteady laminar flow (330⩽Re⩽850) and conjugate heat transfer in the computational domain, which is set up to model the entire fin length in the air flow direction. It was found that the impingement of winglet redirected flow on the downstream tube is an important heat transfer augmentation mechanism for the common-flow-up arrangement of vortex generators in the inline-tube geometry. At Re=850 with a constant tube-wall temperature, the 3VG-inline-array configuration achieves enhancements up to 32% in total heat flux and 74% in j factor over the baseline case, with an associated pressure-drop increase of about 41%. The numerical results for the integral heat transfer quantities agree well with the available experimental measurements.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document