scholarly journals Optimization of heat transfer at the surface of parabolic fins by genetic Algorithm

2017 ◽  
Vol 52 (4) ◽  
pp. 325-330
Author(s):  
A Gholami ◽  
H Mehrjou
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Nusselt Number ◽  
Hydraulic Resistance ◽  
Economic Efficiency ◽  
Heat Exchangers ◽  
Air Conditioning ◽  
Energy Exchanges ◽  
Extended Surfaces ◽  
Library Method

Thermal fins are extended surfaces like longitudinal, radial, and cylindrical fins. They are used for the improvement of heat transfer between an object and fluid. Fins can be applied in many processes of objects cooling such as electrical appliances, many types of engines, transformers, chemical industry, air conditioning, heat exchangers and the industries of energy exchanges. This matter is one of the main results of paying attention to this issue. Therefore, this study examined the optimization of fin heat transfer by using a genetic algorithm and consideration of Nusselt number and hydraulic resistance as the objective function. In this paper, we investigated the optimization of the fin to maximize the heat transfer and also to minimize the hydraulic resistance. The results of this study can be effective in term of technical and economic efficiency in the industry of fin transformer. The stimulation and library method has been used to collect data. The results indicated that if the hydraulic resistance was limited to a specific value, using wavy fins will not improve the device heat.Bangladesh J. Sci. Ind. Res. 52(4), 325-330, 2017

Genetic Algorithm Based Design and Optimization of an Outer-Fins and Inner-Fins Tube Heat Exchanger

2007 ◽  
Author(s):  
G. N. Xie ◽  
M. Zeng ◽  
Q. W. Wang
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Annual Cost ◽  
Total Annual Cost ◽  
Geometrical Parameters ◽  
Tube Heat Exchanger ◽  
Design And Optimization ◽  
Extended Surfaces

One of passive enhancement techniques, Extended Surfaces, are commonly employed in many heat exchangers to enlarge the heat transfer area on gases side because of the low heat transfer coefficients, which may be 10 to 100 times smaller than those of liquids side. The use of extended surfaces (or referred to as finned surfaces) will reduce the thermal resistance of gases side. Enhanced heat transfer coefficient will be achieved by using the basic surface geometries: plate-fin and tube-fin. With respect to the tube-fin type heat exchanger, fins may be employed outside tubes (herein called outer-fins) to enhance the heat transfer of shell-side, and alternatively fins may be also employed inside tubes (herein called inner-fins) to increase the intensity of heat transfer of tube-side. The desire to accomplish the gas-to-gas heat exchange through the tubular heat exchangers will lead to develop heat transfer enhancement techniques for outside and inside tubes. Therefore based on integration with such two mechanisms, namely, outer-fins and inner-fins of enhancement heat transfer techniques, a kind of outer-fins and inner-fins tube heat exchanger has been preliminary proposed (ASME-IGTI, Paper No.2006-90260 [20]). Such heat exchanger is potentially used in gas-to-gas heat exchangers, especially used for highpressure operating conditions, where the plate-fin heat exchangers might not be applicable. In general, the design task is a complex trial-and-error process and there is always the possibility that the design results such as geometrical parameters are not the optimum. Therefore, the motivation of this paper is to conduct optimum designs of such heat exchanger (hereafter called Outer-Fins and Inner-Fins tube Heat Exchanger, OFIF HE). A computational intelligent technique, Genetic Algorithm (GA) is applied to search and optimize geometrical parameters of the OFIF HE. The minimum total volume or minimum total annual cost of such OFIF HE is taken as an objective function in the GA respectively. The results show that the optimized OFIF HE provides lower total volume or lower total annual cost than those presented in previous work. The method is universal and may be used for design and optimization of OFIF HEs under different specified duties and design objectives.

Investigation of heat transfer and hydraulic resistance in small-scale pillow-plate heat exchangers

Energy ◽  
2019 ◽  
Vol 181 ◽  
pp. 1213-1224 ◽  
Author(s):  
Olga Arsenyeva ◽  
Mark Piper ◽  
Alexander Zibart ◽  
Alexander Olenberg ◽  
Eugeny Y. Kenig
Keyword(s):  
Heat Transfer ◽  
Hydraulic Resistance ◽  
Heat Exchangers ◽  
Small Scale ◽  
Plate Heat

Significance of Delta Winglets on the Air Side Performance of Flat Finned Versus Wavy Finned-Tube Heat Exchangers

2020 ◽  
Author(s):  
Tariq Amin Khan ◽  
Nasir Mehdi Gardezi ◽  
Wei Li ◽  
Yang Zhou ◽  
Zahid Ayub
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Heat Exchangers ◽  
Three Dimensional ◽  
Finned Tube ◽  
Maximum Heat ◽  
Multi Objective ◽  
Multi Objective Genetic Algorithm ◽  
Maximum Heat Transfer ◽  
Side Flow

Abstract The performance on the air side flow is often limited due to its lower heat transfer coefficient. This work is related to numerical simulation to study the significance of employing delta winglets in flat finned and wavy finned-tube heat exchangers. For this purpose, three-dimensional simulation data and a multi-objective genetic algorithm are employed. The angle of attack (α) of delta winglets and Reynolds number varied from 15° to 75° and 500 to 1300, respectively. Employing delta winglets has increased the heat transfer per unit temperature and per unit volume (Z) and the fan power per unit core volume (E) for both flat finned and wavy finned-tube heat exchangers. To achieve a maximum heat transfer enhancement and a minimum friction factor, the optimal values of these parameters (Re and α) are calculated using the Pareto optimal strategy. For this purpose, CFD data, a surrogate model (neural network) and a multi-objective optimization genetic algorithm are combined. Results show that the performance of wavy finned-tube heat exchangers is higher than flat-finned tube heat exchangers which signify the importance of delta winglets in the wavy finned-tube heat exchangers.

Laminar Heat Transfer in Rectangular Channels

1959 ◽  
Vol 81 (2) ◽  
pp. 121-127 ◽  
Author(s):  
L. S. Han
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Boundary Conditions ◽  
Heat Input ◽  
Combined Effects ◽  
The Third ◽  
Rectangular Channels ◽  
Free And Forced Convection ◽  
Extended Surfaces ◽  
Rectangular Tubes

Three cases of laminar heat transfer with linear heat input in long rectangular channels have been treated by the method of orthogonal trigonometric series. The boundary conditions of the first two problems are those of laminar and slug flows with two opposite faces as secondary extended surfaces. A new fin parameter K defined as (wkm/bkf) has been shown to be the important factor in governing the Nusselt number. The third case discussed is the combined effects of free and forced-convection in vertical rectangular tubes.

Experimental Investigation of Coil Curvature Effect on Heat Transfer and Pressure Drop Characteristics of Shell and Coil Heat Exchanger

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
M. R. Salem ◽  
K. M. Elshazly ◽  
R. Y. Sakr ◽  
R. K. Ali
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Exchanger ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Average Nusselt Number ◽  
Transfer Coefficients ◽  
Nusselt Numbers ◽  
Fanning Friction Factor ◽  
Coil Heat

The present work experimentally investigates the characteristics of convective heat transfer in horizontal shell and coil heat exchangers in addition to friction factor for fully developed flow through the helically coiled tube (HCT). The majority of previous studies were performed on HCTs with isothermal and isoflux boundary conditions or shell and coil heat exchangers with small ranges of HCT configurations and fluid operating conditions. Here, five heat exchangers of counter-flow configuration were constructed with different HCT-curvature ratios (δ) and tested at different mass flow rates and inlet temperatures of the two sides of the heat exchangers. Totally, 295 test runs were performed from which the HCT-side and shell-side heat transfer coefficients were calculated. Results showed that the average Nusselt numbers of the two sides of the heat exchangers and the overall heat transfer coefficients increased by increasing coil curvature ratio. The average increase in the average Nusselt number is of 160.3–80.6% for the HCT side and of 224.3–92.6% for the shell side when δ increases from 0.0392 to 0.1194 within the investigated ranges of different parameters. Also, for the same flow rate in both heat exchanger sides, the effect of coil pitch and number of turns with the same coil torsion and tube length is remarkable on shell average Nusselt number while it is insignificant on HCT-average Nusselt number. In addition, a significant increase of 33.2–7.7% is obtained in the HCT-Fanning friction factor (fc) when δ increases from 0.0392 to 0.1194. Correlations for the average Nusselt numbers for both heat exchanger sides and the HCT Fanning friction factor as a function of the investigated parameters are obtained.

A Method for Determining the Heat Transfer Properties of Foam-Fins

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Robert J. Moffat ◽  
John K. Eaton ◽  
Andrew Onstad
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Electronic Cooling ◽  
Test Method ◽  
Heat Sinks ◽  
Compact Heat Exchangers ◽  
Extended Surfaces ◽  
Open Cell Foams ◽  
Transfer Properties

Metallic and graphitic open-cell foams are being used or proposed as extended surfaces (fins) in heat sinks for electronic cooling and compact heat exchangers for aircraft applications. Three parameters must be known to calculate the heat transfer performance of a foam-fin: the product hmAc* as a function of flow-rate (the convective conductance per unit volume), the product ksAk* (the effective conductive conductance as a fin), and Rbond (the effective thermal resistance between the foam and the surface to which it is attached). This paper describes a new test method, which, in conjunction with an older well established type of test, allows all three parameters to be measured using one specimen.

scholarly journals COMPUTER PROGRAM FOR CALCULATION MICROCHANNEL HEAT EXCHANGERS FOR AIR CONDITIONING SYSTEMS

2016 ◽  
Vol 52 (3) ◽  
Author(s):  
Olga V. Olshevska
Keyword(s):  
Heat Transfer ◽  
Computer Program ◽  
Heat Exchangers ◽  
Software Package ◽  
Air Conditioning ◽  
Correlation Equation ◽  
Design Time ◽  
Software Packages ◽  
Air Conditioning Systems ◽  
Thermodynamic Equations

Creating a computer program to calculate microchannel air condensers to reduce design time and carrying out variant calculations. Software packages for thermophysical properties of the working substance and the coolant, the correlation equation for calculating heat transfer, aerodynamics and hydrodynamics, the thermodynamic equations for the irreversible losses and their minimization in the heat exchanger were used in the process of creating. Borland Delphi 7 is used for creating software package.

scholarly journals Graphing Behaviour of Heat Transfer In Terms of Nusselt and Reynolds

2021 ◽  
Vol 6 (2) ◽  
pp. 41-52
Author(s):  
Mohd Rahimie Md Noor ◽  
Nur Syafiqah Hidayah Mohd Fauzi ◽  
Siti Nur Fadhilah Masrom ◽  
Mohd Azry Abdul Malek ◽  
Muhammad Firdaus Mustapha ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Volume Flow Rate ◽  
Convection Heat Transfer ◽  
Heat Transfer Process ◽  
Two Fluids ◽  
The Relationship

Heat exchangers are tools used to transfer thermal energy between two fluids (liquid or gas) by convection and conduction at different level of temperatures. Heat exchangers are the common equipment and employed in many different applications because of ability to withstand high temperatures and compactness. There are no intermixing or leakage occurred between two fluids during the heat transfer process as fluids are separated by walls of heat exchanger. The main objective of this project is to determine the heat exchanger effectiveness in heat transfer performance. This will be done by investigating the performance of five different angles of heat exchanger which are 150,300, 450, 600 and 750. The effectiveness of heat exchanger depends on the convection heat transfer coefficient of the fluid. Besides that, this project also aims to develop some parameters such as Nusselt number, Reynolds number and Prandtl number for evaluating the heat transfer. It is found that the Nusselt Number at angle of 150 is lower compared to angle of 750. Meanwhile, Reynolds number for angle 150 is higher than angle 750 which means that the type of flow produced by angle 150 is turbulent flow while for 750 angle is laminar flow. Hence, the overall result of this project proved that 150 is the best angle for heat exchanger in chimney because of higher velocity, higher volume flow rate, higher density of gas and higher LMTD. The relationship between Nusselt number and Reynolds number between different angles can be observed by plotting the graph using Maple Software.

Compact Miniature Heat Exchangers With Advanced Foam-Like Structure

2005 ◽  
Author(s):  
Eugene M. Wexler ◽  
Lev J. Tuchinsky ◽  
Sharly Ibrahim ◽  
Lance J. Milligan
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Convective Heat Transfer ◽  
Hydraulic Resistance ◽  
Convective Heat ◽  
Heat Exchangers ◽  
Transfer Properties

Experimental study has been carried out to investigate convective heat transfer properties of air-cooled foam-like miniature heat exchangers, fabricated using innovative polycapillary materials technology. Practically important results with regard to heat transfer and hydraulic resistance were established and compared for heat exchangers with different structure.

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