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.

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.

A Parametric Study on Fluid Flow and Heat Transfer in a Printed Circuit Heat Exchanger

2011 ◽  
Author(s):  
Sang-Moon Lee ◽  
Kwang-Yong Kim
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Numerical Solutions ◽  
Stokes Equations ◽  
Transport Model ◽  
Three Dimensional ◽  
Design Parameters ◽  
Printed Circuit ◽  
Reference Shape ◽  
Shear Stress Transport Model

Numerical analyses for pressure drop and heat transfer in the flow channels of a printed circuit heat exchanger have been performed numerically. Three-dimensional Reynolds-averaged Navier-Stokes equations have been solved in conjunction with the shear stress transport model as a turbulence closure. The numerical solutions are validated with the available experimental results of the reference shape. The effects of two design parameters, namely, the channel angle and the ellipse aspect ratio of the cold channel, on the heat transfer and the friction performance have been evaluated.

Flow and Heat Transfer From the Annular Fin Heat Exchanger Using Winglet Type Vortex Generators

2013 ◽  
Author(s):  
Basanta Kumar Rana ◽  
Amaresh Dalal ◽  
Gautam Biswas
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Exchanger ◽  
Thermal Boundary Layer ◽  
Numerical Study ◽  
Three Dimensional ◽  
Vortex Generators ◽  
Flow And Heat Transfer ◽  
Finned Tube Heat Exchanger ◽  
Annular Fin

A numerical study of three-dimensional flow and heat transfer from the annular finned tube heat exchanger with built-in delta winglets is carried out. The delta winglets type vortex generators which are placed on the annular fin surface in the neighborhood of the cylinder are used to enhance the heat transfer. The winglets are placed in common flow orientation. Longitudinal vortices develop along the side edge of the delta winglets due to the pressure difference between the front surface (facing the flow) and back surface. These vortices interact with thermal boundary layer and produce a three dimensional swirling flow that mixes near wall fluid with the midstream. Thus the thermal boundary layer is disrupted and heat transfer is enhanced. The investigations are carried out for four different Reynolds number (100, 500 and 1000) and four different angles of attack (35°, 40°, 45°, 50°) for common flow up (CFU) configuration. It is found that heat transfer increases about 11% for Re = 1000 with angle of attack 40°.

Numerical Simulation of the Flow and Heat Transfer of Fractal Tree-Like Minichannel Heat Exchanger

2015 ◽  
Vol 1092-1093 ◽  
pp. 525-528
Author(s):  
Jian Sun ◽  
Zhang Feng Huang ◽  
Ren Ping Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Three Dimensional ◽  
Boundary Surface ◽  
Heat Transfer Process ◽  
Transfer Model ◽  
Temperature Uniformity ◽  
Flow And Heat Transfer ◽  
Symmetric Structure ◽  
Minichannel Heat Exchanger

A three-dimensional steady-state laminar flow and heat transfer model for fractal tree-like minichannel heat exchanger is developed.The fluid flow and heat transfer process is studied by CFD software. Because of its symmetric structure, only half body of the heat exchanger is calculated. The fluid-solid coupled method is applied and the hexahedral grid is used on the control volume.The temperature distribution and velocity distribution for different heat flux on top boundary surface are obtained with an inlet hydraulic diameter of 3.2mm.The simulated results show that the fractal tree-like minichannel heat exchanger has good temperature uniformity and small pressure drop.

Combined Enhancement Techniques on Double Tube Heat Exchanger Using Nanofluid and Helicoid Tube Shape

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Yousef Alhendal ◽  
Abdalla Gomaa ◽  
Mahmoud Abdelmagied
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Design Parameters ◽  
Coiled Tube ◽  
Tube Heat Exchanger ◽  
Points Of Interest ◽  
Level Of Details ◽  
Tube Shape

Abstract The thermofluid characteristics of Al2O3–water nanofluid in the annulus of double-helical coiled tubes were experimentally and numerically carried out. The purpose was to investigate the effect of combined enhancement techniques of nanofluid and helicoid tube shape on the performance of a double tube heat exchanger. The effects of concentration of nanoparticles, Reynolds number, coil curvature ratio, and flow arrangement through the annulus of double-helical coiled tube were the main points of interest. Three coiled tube heat exchangers were manufactured and experimentally tested to study the design parameters on the performance of such a heat exchanger. A three-dimensional numerical computational fluid dynamic (CFD) model was developed to get additional insights on the thermal performance of double helically coiled tubes with nanofluid on a level of details not always available in experiments. It was found that the Al2O3–water nanofluid achieved an enhancement by 32% on the overall heat transfer coefficient. The heat exchanger effectiveness, heat transfer per unit pumping power, and the Nusselt number were also presented for different design parameters.

Heat Transfer Investigation of an Additively Manufactured Minichannel Heat Exchanger

2019 ◽  
Author(s):  
Hamidreza Rastan ◽  
Amir Abdi ◽  
Monika Ignatowicz ◽  
Bejan Hamawandi ◽  
Poh Seng Lee ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Single Phase ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Working Fluid ◽  
Minichannel Heat Exchanger ◽  
Simulation Results ◽  
Good Agreement

Abstract This study investigates the thermal performance of laminar single-phase flow in an additively manufactured minichannel heat exchanger both experimentally and numerically. Distilled water was employed as the working fluid, and the minichannel heat exchanger was made from aluminum alloy (AlSi10Mg) through direct metal laser sintering (DMLS). The minichannel was designed with a hydraulic diameter of 2.86 mm. The Reynolds number ranged from 175 to 1360, and the heat exchanger was tested under two different heat fluxes of 1.5 kWm−2 and 3 kWm−2. A detailed experiment was conducted to obtain the thermal properties of AlSi10Mg. Furthermore, the heat transfer characteristics of the minichannel heat exchanger was analyzed numerically by solving a three-dimensional conjugate heat transfer using the COMSOL Multiphysics® to verify the experimental results. The experimental results were also compared to widely accepted correlations in literature. It is found that 95% and 79% of the experimental data are within ±10% range of both the simulation results and the values from the existing correlations, respectively. Hence, the good agreement found between the experimental and simulation results highlights the possibility of the DMLS technique as a promising method for manufacturing future multiport minichannel heat exchangers.

scholarly journals Thermal Analysis on Hydrothermal Performance of Double Pipe Heat Exchanger with Single and Double Helical Tape

2019 ◽  
Vol 9 (2) ◽  
pp. 1965-1972
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Industrial Process ◽  
Design Parameters ◽  
Cfd Simulations ◽  
Economic Point ◽  
Double Pipe ◽  
Pipe Heat

Double pipe heat exchanger has wide applications in industrial process. Thermo-hydro performance plays an important role from the economic point of view. Different enhancement techniques are available for the improvement of heat transfer. In this study the hydrothermal performance of double pipe heat exchanger with single and double HTI on inner pipe of double pipe heat exchanger were experimentally examined. Two types of inner tubes with single and double helical tape was fabricated. Experiments were performed by different mass flow rate of annulus side in the range of 0.072- 0.21 kg/s varied. In order to validate the result three dimensional CFD simulations are performed, using Fluent software. CFD simulations analysis was done under turbulent flow conditions. Key design parameters such as heat transfer coefficient and Nusselt number are evaluated in order to predict the performance of DPHE. Findings from this study shows that hydrothermal performance of double pipe heat exchanger with double helical tape is better than single HTI. Moreover both the results of CFD simulation & experimental one are in good agreement. Therefore, the present study will help the manufacturers in providing the better thermal performance of DPHE.

scholarly journals Effect of buried depth on thermal performance of a vertical U-tube underground heat exchanger

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 327-330
Author(s):  
Li Yang ◽  
Bo Zhang ◽  
Jiří Jaromír Klemeš ◽  
Jie Liu ◽  
Meiyu Song ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Simplified Model ◽  
Two Dimensional ◽  
Construction Sites ◽  
Full Size ◽  
Unit Depth ◽  
Research Show

Abstract Many researchers numerically investigated U-tube underground heat exchanger using a two-dimensional simplified pipe. However, a simplified model results in large errors compared to the data from construction sites. This research is carried out using a three-dimensional full-size model. A model validation is conducted by comparing with experimental data in summer. This article investigates the effects of fluid velocity and buried depth on the heat exchange rate in a vertical U-tube underground heat exchanger based on fluid–structure coupled simulations. Compared with the results at a flow rate of 0.4 m/s, the results of this research show that the heat transfer per buried depth at 1.0 m/s increases by 123.34%. With the increase of the buried depth from 80 to 140 m, the heat transfer per unit depth decreases by 9.72%.

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