Film Condensation of R-113 on Staggered Bundles of Horizontal Finned Tubes

1992 ◽  
Vol 114 (2) ◽  
pp. 442-449 ◽  
Author(s):  
H. Honda ◽  
B. Uchima ◽  
S. Nozu ◽  
E. Torigoe ◽  
S. Imai
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Three Dimensional ◽  
Film Condensation ◽  
Line Bundles ◽  
Heat Transfer Characteristics ◽  
Finned Tubes ◽  
Flow And Heat Transfer ◽  
Fin Tubes ◽  
Annular Fins

Film condensation of R-113 on staggered bundles of horizontal finned tubes with vertical vapor downflow was experimentally investigated. Two tubes with flat-sided annular fins and four tubes with three-dimensional fins were tested. The condensate flow and heat transfer characteristics were compared with the previous results for in-line bundles of the same test tubes and a staggered bundle of smooth tubes. The decrease in heat transfer due to condensate inundation was most significant for the in-line bundles of the three-dimensional fin tubes, whereas the decrease was very slow for both the staggered and in-line bundles of the flat-sided fin tubes. The predictions of the previous theoretical model for a bundle of flat-sided fin tubes agreed fairly well with the measured data at a low vapor velocity. The highest heat transfer performance was provided by the staggered bundle of flat-sided fin tubes with fin dimensions close to the theoretically determined optimum values.

Film Condensation of R-113 on In-Line Bundles of Horizontal Finned Tubes

1991 ◽  
Vol 113 (2) ◽  
pp. 479-486 ◽  
Author(s):  
H. Honda ◽  
B. Uchima ◽  
S. Nozu ◽  
H. Nakata ◽  
E. Torigoe
Keyword(s):  
Heat Transfer ◽  
Tube Bundle ◽  
Three Dimensional ◽  
Finned Tube ◽  
Film Condensation ◽  
Line Bundles ◽  
Finned Tubes ◽  
Fin Tube ◽  
Fin Tubes ◽  
Annular Fins

Film condensation of R-113 on in-line bundles of horizontal finned tubes with vertical vapor downflow was experimentally investigated. Two tubes with flat-sided annular fins and four tubes with three-dimensional fins were tested. The test sections were 3×15 tube bundles with and without two rows of inundation tubes at the top. Heat transfer measurements were carried out on a row-by-row basis. The heat transfer enhancement due to vapor shear was much less for a finned tube bundle than for a smooth tube bundle. The decrease in heat transfer due to condensate inundation was more marked for a three-dimensional fin tube than for a flat-sided fin tube. The predictions of the previous theoretical model for a bundle of flat-sided fin tubes agreed well with the measured data for low vapor velocity and a small to medium condensate inundation rate. Among the six tubes tested, the highest heat transfer performance was provided by the flat-sided fin tube with fin dimensions close to the theoretically determined optimum values.

Enhanced Condensation Heat-Transfer on Mini or Low Fin Tubes

2006 ◽  
Author(s):  
Adrian Briggs
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Thermophysical Properties ◽  
Heat Transfer Performance ◽  
Three Dimensional ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Shell Side ◽  
Wide Range ◽  
Fin Tubes

This paper presents an overview of the use of low or mini-fin tubes for improving heat-transfer performance in shell-side condensers. The paper concentrates on, but is not limited to, the experimental and theoretical program in progress at Queen Mary, University of London. This work has so far resulted in an extensive data base of experimental data for condensation on single tubes, covering a wide range of tube geometries and fluid thermophysical properties and in the development of a simple to use model which predicts the majority of this data to within 20%. Work is progressing on the effects of vapor shear and on three-dimensional fin profiles; the later having shown the potential for even higher heat-transfer enhancement.

Three Dimensional Numerical Simulation of the Natural Convection in an Annulus With an Internal Slotted Cylinder

2011 ◽  
Author(s):  
Mo Yang ◽  
Jin Wang ◽  
Kun Zhang ◽  
Ling Li ◽  
Yuwen Zhang
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Dimensional Model ◽  
Heat Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Rayleigh Numbers

Detailed numerical analysis is presented for three-dimensional natural convection heat transfer in annulus with an internal concentric slotted cylinder. The internal slotted cylinder and the outer annulus are maintained at uniform but different temperatures. Governing equations are discretized using control volume technique based on staggered grid formulation and solved using SIMPLE algorithm with QUICK scheme. Flow and heat transfer characteristics are investigated for a Rayleigh number range of 10 to 106 while Prandtl number (Pr) is taken to be 0.7. The results indicate, at Rayleigh numbers below 105, the system shows two dimensional flow and heat transfer characteristics. On the other hand, the flow and heat transfer shows three dimensional characteristics while for Rayleigh numbers greater than 5×105. Comparison with experimental results indicated that the numerical solutions by three dimensional model can obtain more accuracy than the numerical solutions by two dimensional model. Besides, Numerical results show that the average equivalent conductivity coefficient of natural convection heat transfer of this problem can be enhanced by as much as 30% while relative slot width is more than 0.1.

Numerical Analysis of Blockage and Optimization of Heat Transfer Performance of Fractal-like Microchannel Nets

2005 ◽  
Vol 128 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Xiang-Qi Wang ◽  
Arun S. Mujumdar ◽  
Christopher Yap
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Flow Resistance ◽  
Heat Transfer Performance ◽  
Three Dimensional ◽  
Constant Heat Flux ◽  
Low Flow ◽  
Flow And Heat Transfer ◽  
Computational Fluid Dynamics Cfd ◽  
Number Of Branches

The conjugate fluid flow and heat transfer characteristics of fractal-like microchannel nets embedded in a disk-shape heat sink are investigated using a three-dimensional computational fluid dynamics (CFD) approach. A constant heat flux is applied to the top wall of the heat sink. The intrinsic advantages of fractal-like microchannel nets such as low flow resistance, temperature uniformity, and reduced danger of blockage compared with the traditional parallel channel nets are demonstrated. In addition, various optimized designs with parameters such as the number of branches, number of branching levels, and number of channels that reach the center of the disk are addressed in this context.

scholarly journals The Effect of Geometrical Parameters on Heat Transfer Characteristics of Compact Heat Exchanger with Louvered Fins

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
P. Gunnasegaran ◽  
N. H. Shuaib ◽  
M. F. Abdul Jalal
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Three Dimensional ◽  
Cross Flow ◽  
Geometrical Parameters ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Drop Flow ◽  
Louvered Fins

Compact heat exchangers (CHEs) have been widely used in various applications in thermal fluid systems including automotive thermal management systems. Among the different types of heat exchangers for engine cooling applications, cross-flow CHEs with louvered fins are of special interest because of their higher heat rejection capability with the lower flow resistance. In this study, the effects of geometrical parameters such as louver angle and fin pitch on air flow and heat transfer characteristics on CHEs are numerically investigated. Numerical investigations using five different cases with increased and decreased louver angles (+2°, +4°, −2°, −4°, and uniform angle 20°), with a fixed fin pitch and using three different fin pitches (1.0 mm, 2.0 mm, and 4.0 mm), and with the fixed louver angle are examined. The three-dimensional (3D) governing equations for the fluid flow and heat transfer are solved using a standard finite-volume method (FVM) for the range of Reynolds number between 100 and 1000. The computational model is used to study the variations of pressure drop, flow temperature, and Nusselt number.

Numerical Study of Flow and Heat Transfer Characteristics of Impinging Jets

2010 ◽  
Author(s):  
Tarek M. Abdel-Salam
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Numerical Study ◽  
Three Dimensional ◽  
Impinging Jets ◽  
Two Dimensional ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer

This study presents results for flow and heat transfer characteristics of two-dimensional rectangular impinging jets and three-dimensional circular impinging jets. Flow geometries under consideration are single and multiple impinging jets issued from a plane wall. Both confined and unconfined configurations are simulated. Effects of Reynolds number and the distance between the jets are investigated. Results are obtained with a finite volume computational fluid dynamics (CFD) code. Structured grids are used in all cases of the present study. Turbulence is treated with a two equation k-ε model. Different jet velocities have been examined corresponding to Reynolds numbers of 5,000 to 20,000. Results of the three-dimensional cases show that Reynolds number has no effect on the velocity distribution of the center jet. Results of both two-dimensional and three-dimensional cases show that Reynolds number highly affects the heat transfer and values of the Nusselt number. The maximum Nusselt number was always found at the stagnation point of the center jet.

Film Condensation of R-11 Vapor on Single Horizontal Enhanced Condenser Tubes

1990 ◽  
Vol 112 (1) ◽  
pp. 229-234 ◽  
Author(s):  
S. P. Sukhatme ◽  
B. S. Jagadish ◽  
P. Prabhakaran
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Film Condensation ◽  
Vertex Angle ◽  
Transfer Performance ◽  
Enhancement Ratio ◽  
Maximum Value ◽  
Enhanced Tubes ◽  
Fin Tubes ◽  
The Heat Transfer Coefficient

The heat transfer performance of R-11 vapor condensing on single horizontal trapezodially shaped integral-fin tubes has been investigated by systematically varying the fin density, the semi-vertex angle, and the fin height. For the nine copper tubes tested, the best performance has been obtained with a tube having a fin density of 1417 fpm, a semi-vertex angle of 10 deg, and a fin height of 1.22 mm. This tube has yielded a maximum value of the heat transfer coefficient of 16,500 W/m2 K at a ΔT of about 3 K, corresponding to an enhancement ratio of 10.3. The performance of the tube has been further improved by fabricating from it “specially enhanced” tubes having axial grooves of varying height. An enhancement ratio of 12.3 has been obtained with this type of tube.

Sign in / Sign up

Export Citation Format

Share Document