Heat Transfer in Internally Finned Tubes

1976 ◽  
Vol 98 (2) ◽  
pp. 257-261 ◽  
Author(s):  
J. H. Masliyah ◽  
K. Nandakumar
Keyword(s):  
Heat Transfer ◽  
Circular Tube ◽  
Uniform Heat Flux ◽  
Heat Transfer Characteristics ◽  
Fully Developed Flow ◽  
Maximum Heat ◽  
Finned Tubes ◽  
Maximum Heat Transfer ◽  
Internal Fins ◽  
Laminar Forced Convection

Heat transfer characteristics for a laminar forced convection fully developed flow in an internally finned circular tube with axially uniform heat flux with peripherally uniform temperature are obtained using a finite element method. For a given fin geometry, the Nusselt number based on inside tube diameter was higher than that for a smooth tube. Also, it was found that for maximum heat transfer there exists an optimum fin number for a given fin configuration. The internal fins are of triangular shape.

Parametric Analysis of a Bayonet Tube With a Special Type of Extended Surface

2010 ◽  
Author(s):  
L. Almanza-Huerta ◽  
A. Hernandez-Guerrero ◽  
M. Krarti ◽  
J. M. Luna
Keyword(s):  
Heat Transfer ◽  
Parametric Analysis ◽  
Numerical Study ◽  
Systematic Investigation ◽  
Heat Transfer Characteristics ◽  
Maximum Heat ◽  
Turbulent Transition ◽  
Maximum Heat Transfer ◽  
Internal Fluid ◽  
Extended Surface

The present paper provides a numerical study of a parametric analysis of a bayonet tube with a special type of extended surface during the laminar-turbulent transition. The working internal fluid is air. Attention is focused on the heat transfer characteristics of the tube. The results constitute a systematic investigation of the effect of the extended surface located along the annulus of the bayonet on the overall heat transfer rate. The effects of the variation of some parameters related to the extended surface aiming to attain the maximum heat transfer with the minimum pressure drop are discussed. Comparisons between designs with and without extended surface are also made.

Static configuration of liquid films on horizontal tubes with low radial fins: implications for condensation heat transfer

1987 ◽  
Vol 410 (1838) ◽  
pp. 125-139 ◽  
Keyword(s):  
Heat Transfer ◽  
Liquid Films ◽  
Finned Tube ◽  
Tube Surface ◽  
Maximum Heat ◽  
Finned Tubes ◽  
Horizontal Tubes ◽  
Maximum Heat Transfer ◽  
Fluid Properties ◽  
Static Conditions

The configuration of a liquid film retained by surface tension forces on horizontal low-finned tubes has been analysed. It has been shown that liquid is retained on the upper parts of the tube surface previously regarded as 'unflooded'. The meniscus in a radial plane has been shown to approximate to a circular arc, with radius dependent only on the distance from the bottom of the tube, fluid properties and gravity. Four ‘flooding’ conditions are identified for trapezoidal-section fins and the positions around a tube at which these occur have been determined. Experimental measurements, for condensation of three fluids on tubes with rectangular-section fins, suggest that maximum heat-transfer en­hancement occurs when the spacing between the fins (the only geometric variable in these tests) is such as to maximize the ‘unblanked’ (by retained liquid under static conditions) finned tube surface area. The ‘unblanked’ or ‘active’ area is increased by using a radiused fillet at the fin root rather than a sharp corner. This might also be expected to give a corresponding increase in heat-transfer enhancement during condensation.

Maximum Heat Transfer From Multi-Scale Fins Arranged in a Row With Non-Uniform Geometry

2010 ◽  
Author(s):  
T. Bello-Ochende ◽  
J. P. Meyer ◽  
A. Bejan
Keyword(s):  
Heat Transfer ◽  
Free Stream ◽  
Thermal Conductivity Ratio ◽  
Total Heat Transfer ◽  
Maximum Heat ◽  
Optimum Configuration ◽  
Multi Scale ◽  
Maximum Heat Transfer ◽  
Pin Fins ◽  
Laminar Forced Convection

This paper described numerical the procedure used to determine the optimum configuration of two rows of pin fins so that the total heat transfer rate is maximized. The heat transfer across the fins is by laminar forced convection bathed by a free-stream that is uniform and isothermal. The optimization is subjected to fixed volume of fin materials. The dimensions of the optimized configuration are the result of balancing conduction along the fins with convection transversal to the fins. Numerical results on the effect of dimensionless pressure drop and the thermal conductivity ratio on the optimal configuration are reported. Results obtained from numerical analyses are comparable to those in the open literature. The results also show that the flow structure performs best when the fin diameters and heights are non-uniform.

Heat Transfer of Sprays of Large Water Drops Impacting on High Temperature Surfaces

1999 ◽  
Vol 121 (2) ◽  
pp. 446-450 ◽  
Author(s):  
T. L. Cox ◽  
S. C. Yao
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Current Data ◽  
Large Droplet ◽  
Heat Transfer Characteristics ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Water Drops ◽  
Large Water ◽  
Transfer Potential

Experiments were performed to evaluate the heat transfer of monodisperse sprays of large droplet diameters, ranging from 3 to 25 mm, on high temperature surfaces. This range of drop sizes has not previously been studied, and it was of interest to determine their heat transfer characteristics and how they relate to sprays of smaller drops. Parametric tests showed that the spray heat flux depends on mass flux with a power-law relationship, and that spray effectiveness, which relates the actual spray heat transfer to the maximum heat transfer potential, varies with d−1/2. There was no discernible relationship between the heat transfer and droplet velocity. These results agreed favorably with published results for smaller droplets. The current data was compared to previous tests with smaller droplets using the droplet Reynolds and Weber numbers. This analysis showed some grouping, with a marked separation at We = 80, where the dynamic behavior of droplets has been shown to change for nonwetting impaction.

Optimal Configuration of Vortex Generator for Heat Transfer Enhancement in a Plate-Fin Channel

2017 ◽  
Vol 10 (2) ◽  
Author(s):  
Tariq Amin Khan ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Numerical Simulations ◽  
Three Dimensional ◽  
Vortex Generator ◽  
Design Parameters ◽  
Heat Transfer Characteristics ◽  
Maximum Heat ◽  
Transfer Characteristics ◽  
Maximum Heat Transfer ◽  
Independent Design

Heat transfer is a naturally occurring phenomenon and its augmentation is a vital research topic for many years. Although, vortex generators (VGs) are widely used to enhance the heat transfer of plate-fin type heat exchangers, few researches deal with its thermal optimization. This work is dedicated to the numerical investigation and optimization of VGs configuration in a plate-fin channel. Three-dimensional (3D) numerical simulations are performed to study the effect of angle of attack and attach angle (angle between VG and wall) and shape of VG on the fluid flow and heat transfer characteristics. The flow is assumed as steady-state, incompressible, and laminar within the range of studied Reynolds numbers (Re = 380–1140). Results are presented in the form average and local Nusselt number and friction factor. The effect of attach angle is highlighted and the results show that the attach angle of 90 deg may not be necessary for enhancing the heat transfer. The flow structure and heat transfer characteristics of certain cases are examined in detail. The parameters of VG are then optimized for maximum heat transfer and minimum pressure drop. The three independent design parameters are considered for the two objective functions. For this purpose, computation fluid dynamics (CFD) data, response surface methodology (RSM) and a multi-objective optimization algorithm (MOA) are combined. The data obtained from numerical simulations are used to train a Bayesian-regularized artificial neural network (BRANN). This in turn is used to drive a MOA to find the optimal parameters of VGs in the form of Pareto front. The optimal values of these parameters are finally presented.

scholarly journals Optimization Performance on Plate Fin Tube Heat Exchanger

2019 ◽  
Vol 5 (3) ◽  
pp. 10
Author(s):  
Mahtab Alam ◽  
Dr. Dharmendra Singh Rajput
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Circular Tube ◽  
Fluid Dynamic ◽  
Cfd Analysis ◽  
Maximum Heat ◽  
Tube Heat Exchanger ◽  
Tube Arrangement ◽  
Maximum Heat Transfer ◽  
Fin Tube

The main objective of the present work is to investigation of optimum design of plate fin tube heat exchanger using Computational fluid dynamic approach and maximizing thermal performance. There are total five designs of plate fin and tube heat exchanger are used in present work and CFD analysis have been performed in it to get maximum heat transfer. It has been observed from CFD analysis that the maximum heat transfer can be achieved from plate fin and tube heat exchanger with elliptical tube arrangement inclined at 30o with 23.22% more heat transfer capacity as compared to circular tube plate pin heat exchanger. So that it is recommended that if the plate fins and tube heat exchanger with inclined elliptical tube used in place of circular tube arrangement, batter heat transfer can be achieved.

scholarly journals Optimizing Thermal Behavior of Flat Plate Heat Exchanger Tube by Varying Geometrical Configuration

2020 ◽  
pp. 13-25
Author(s):  
Nitesh Kumar Singh
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Circular Tube ◽  
Fluid Dynamic ◽  
High Ratio ◽  
Cfd Analysis ◽  
Maximum Heat ◽  
Tube Heat Exchanger ◽  
Tube Arrangement ◽  
Maximum Heat Transfer

A plate fin heat exchanger is a type of heat exchanger design that uses plates and finned chambers to transfer heat between liquids. It is often classified as a compact heat exchanger to emphasize the relatively high ratio between the heat transfer surface and the volume. The main objective of the present work is to investigation of optimum design of plate fin tube heat exchanger using Computational fluid dynamic approach and maximizing thermal performance. There are total five designs of plate fin and tube heat exchanger are used in present work and CFD analysis have been performed in it to get maximum heat transfer. It has been observed from CFD analysis that the maximum heat transfer can be achieved from plate fin and tube heat exchanger with elliptical tube arrangement inclined at 30o with 23.22% more heat transfer capacity as compared to circular tube plate pin heat exchanger. So that it is recommended that if the plate fins and tube heat exchanger with inclined elliptical tube used in place of circular tube arrangement, batter heat transfer can be achieved.

scholarly journals Development of Forced Convection Heat Transfer Enhancement System by using Mesh Inserts in a Circular Tube

2021 ◽  
Author(s):  
Avinash D. Sapkal ◽  
Akash A Pawar ◽  
Shridhar V Kulkarni ◽  
Umesh B Andh ◽  
Digambar T Kashid ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Flow Rate ◽  
Test Section ◽  
Circular Tube ◽  
Convection Heat Transfer ◽  
Transfer Enhancement ◽  
Measure Flow Rate ◽  
Maximum Heat ◽  
Maximum Heat Transfer

In the present work, aluminium mesh type inserts flow has been developed. The aluminium meshes are arranged on spokes at the angle of 00, 450, 900 concerning horizontal are inserted in the test section to create turbulence. To carry out an experimental investigation using this mesh inserts, we have developed a forced convection system. In this system, we have wounded three 200 Volt heaters over a 500 mm test section of 25 mm diameter respectively. The input to the heater is controlled by a variable dimmer stat, and the mass flow rate is controlled by an orifice meter with a diameter of 25 mm across which the manometer is connected to measure flow rate. Experiments were carried out at Reynolds number greater than 4000. The experimental setup was validated first and readings with different inserts were taken. This led to the conclusion that the rate of heat transfer was improved by using mesh inserts inclined at an angle 00, 450, and 900. Among these, the inserts inclined at 450 angles showed maximum heat transfer rate i.e., 37.44%, 29.95%, and 38.40% for the manometric reading of 5 mm, 4 mm, and 3 mm respectively.

scholarly journals Flow and heat transfer characteristics downstream of a porous sudden expansion: A numerical study

2011 ◽  
Vol 15 (2) ◽  
pp. 389-396 ◽  
Author(s):  
Khalid Alammar
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Darcy Number ◽  
Sudden Expansion ◽  
Heat Transfer Characteristics ◽  
Maximum Heat ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Maximum Heat Transfer ◽  
Inertia Coefficient

Incompressible, axisymmetric laminar flow downstream of a porous expansion is simulated. Effect of the Darcy number and inertia coefficient on flow and heat transfer characteristics downstream of the expansion is investigated. The simulation revealed circulation downstream of the expansion. Decreasing the Darcy number is shown to decrease the circulation region. The Nusselt number, friction coefficient, and pressure drop are shown to increase, while reattachment and location of maximum heat transfer move upstream with decreasing Darcy number. Similar effects are observed with increasing inertia coefficient.

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