scholarly journals Shell-side single-phase flows and heat transfer in shell-and-tube heat exchangers. 3rd Report. Experimental study on axial and circumferential distribution of local heat transfer coefficients around a tube bundle.

1987 ◽  
Vol 53 (488) ◽  
pp. 1344-1350
Author(s):  
Hitoshi MATSUSHIMA ◽  
Takehiko YANAGIDA ◽  
Wataru NAKAYAMA ◽  
Akio KUDO
Keyword(s):  
Heat Transfer ◽  
Single Phase ◽  
Tube Bundle ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Shell Side ◽  
Heat Transfer Coefficients ◽  
Circumferential Distribution ◽  
Shell And Tube

Local Heat Transfer Coefficients Under an Axisymmetric, Single-Phase Liquid Jet

1991 ◽  
Vol 113 (1) ◽  
pp. 71-78 ◽  
Author(s):  
J. Stevens ◽  
B. W. Webb
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Local Nusselt Number ◽  
Single Phase ◽  
Radial Distance ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Plate Spacing

The purpose of this investigation was to characterize local heat transfer coefficients for round, single-phase free liquid jets impinging normally against a flat uniform heat flux surface. The problem parameters investigated were jet Reynolds number Re, nozzle-to-plate spacing z, and jet diameter d. A region of near-constant Nusselt number was observed for the region bounded by 0≤r/d≤0.75, where r is the radial distance from the impingement point. The local Nusselt number profiles exhibited a sharp drop for r/d > 0.75, followed by an inflection and a slower decrease there-after. Increasing the nozzle-to-plate spacing generally decreased the heat transfer slightly. The local Nusselt number characteristics were found to be dependent on nozzle diameter. This was explained by the influence of the free-stream velocity gradient on local heat transfer, as predicted in the classical analysis of infinite jet stagnation flow and heat transfer. Correlations for local and average Nusselt numbers reveal an approximate Nusselt number dependence on Re1/3.

Local Heat Transfer Coefficients for Horizontal Tube Arrays in High-Temperature Large-Particle Fluidized Beds: An Experimental Study

1986 ◽  
Vol 108 (4) ◽  
pp. 907-912 ◽  
Author(s):  
A. Goshayeshi ◽  
J. R. Welty ◽  
R. L. Adams ◽  
N. Alavizadeh
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
High Temperature ◽  
Tube Bundle ◽  
Local Heat Transfer ◽  
Horizontal Tube ◽  
Packed Bed ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

An experimental study is described in which time-averaged local heat transfer coefficients were obtained for arrays of horizontal tubes immersed in a hot fluidized bed. Bed temperatures up to 1005 K were achieved. Bed particle sizes of 2.14 mm and 3.23 mm nominal diameter were employed. An array of nine tubes arranged in three horizontal rows was used. The 50.8 mm (2 in.) diameter tubes were arranged in an equilateral triangular configuration with 15.24 cm (6 in.) spacing between centers. The center tube in each of the three rows in the array was instrumented providing data for local heat flux and surface temperature at intervals of 30 deg from the bottom to the top—a total of seven sets of values for each of the center tubes. The three sets of data are representative of the heat transfer behavior of tubes at the bottom, top, and in the interior of a typical array. Data were also obtained for a single horizontal tube to compare with the results of tube bundle performance. Superficial velocities of high-temperature air ranged from the packed-bed condition through approximately twice the minimum fluidization level. Comparisons with results for a single tube in a bubbling bed indicate only slight effects on local heat transfer resulting from the presence of adjacent tubes. Tubes in the bottom, top, and interior rows also exhibited different heat transfer performance.

A Parametric Study of Boiling Heat Transfer in a Horizontal Tube Bundle

1988 ◽  
Vol 110 (4a) ◽  
pp. 976-981 ◽  
Author(s):  
M. K. Jensen ◽  
J.-T. Hsu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Tube Bundle ◽  
Local Heat Transfer ◽  
Horizontal Tube ◽  
Local Heat ◽  
Heat Fluxes ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Boiling heat transfer outside of a section of a uniformly heated horizontal tube bundle in an upward crossflow was investigated using R-113 as the working fluid. The inline tube bundle had five columns and 27 rows with a pitch-to-diameter ratio of 1.3. Heat transfer coefficients obtained from the 14 instrumented tubes are reported for a range of fluid and flow conditions; slightly subcooled liquid inlet conditions were used. At most heat fluxes there was no significant variation in the local heat transfer coefficients throughout the tube bundle. However, at low heat fluxes and mass velocities, the heat transfer coefficient increased at positions higher in the tube bundle. As pressure and mass velocity increased so did the heat transfer coefficients. For the local heat transfer coefficient, a Chen-type correlation is compared to the data; the data tend to be overpredicted by about 20 percent. Reasons for the overprediction are suggested.

The Effect of Regulating Elements on Convective Heat Transfer along Shaped Heat Exchange Surfaces

2013 ◽  
Vol 34 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Jozef Cernecky ◽  
Jan Koniar ◽  
Zuzana Brodnianska
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Cfd Simulation ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Temperature Fields ◽  
Transfer Coefficients ◽  
Heat Transfer Intensification ◽  
Heat Transfer Coefficients ◽  
Forced Air

Abstract The paper deals with a study of the effect of regulating elements on local values of heat transfer coefficients along shaped heat exchange surfaces with forced air convection. The use of combined methods of heat transfer intensification, i.e. a combination of regulating elements with appropriately shaped heat exchange areas seems to be highly effective. The study focused on the analysis of local values of heat transfer coefficients in indicated cuts, in distances expressed as a ratio x/s for 0; 0.33; 0.66 and 1. As can be seen from our findings, in given conditions the regulating elements can increase the values of local heat transfer coefficients along shaped heat exchange surfaces. An optical method of holographic interferometry was used for the experimental research into temperature fields in the vicinity of heat exchange surfaces. The obtained values correspond very well with those of local heat transfer coefficients αx, recorded in a CFD simulation.

scholarly journals Heat Transfer Coefficient Determination in a Gravity Die Casting Process with Local Air Gap Formation and Contact Pressure Using Experimental Evaluation and Numerical Simulation

2021 ◽  
Author(s):  
T. Vossel ◽  
N. Wolff ◽  
B. Pustal ◽  
A. Bührig-Polaczek ◽  
M. Ahmadein
Keyword(s):  
Heat Transfer ◽  
Contact Pressure ◽  
Local Heat Transfer ◽  
Casting Process ◽  
Local Heat ◽  
Air Gap ◽  
Gap Formation ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Die Casting Process

AbstractAnticipating the processes and parameters involved for accomplishing a sound metal casting requires an in-depth understanding of the underlying behaviors characterizing a liquid melt solidifying inside its mold. Heat balance represents a major factor in describing the thermal conditions in a casting process and one of its main influences is the heat transfer between the casting and its surroundings. Local heat transfer coefficients describe how well heat can be transferred from one body or material to another. This paper will discuss the estimation of these coefficients in a gravity die casting process with local air gap formation and heat shrinkage induced contact pressure. Both an experimental evaluation and a numerical modeling for a solidification simulation will be performed as two means of investigating the local heat transfer coefficients and their local differences for regions with air gap formation or contact pressure when casting A356 (AlSi7Mg0.3).

scholarly journals Condensation inside smooth horizontal tubes: Part 1. Survey of the methods of heat-exchange prediction

2015 ◽  
Vol 19 (5) ◽  
pp. 1769-1789 ◽  
Author(s):  
Volodymyr Rifert ◽  
Volodymyr Sereda
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Film Condensation ◽  
Experimental Investigations ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Horizontal Tubes

Survey of the works on condensation inside smooth horizontal tubes published from 1955 to 2013 has been performed. Theoretical and experimental investigations, as well as more than 25 methods and correlations for heat transfer prediction are considered. It is shown that accuracy of this prediction depends on the accuracy of volumetric vapor content and pressure drop at the interphase. The necessity of new studies concerning both local heat transfer coefficients and film condensation along tube perimeter and length under annular, stratified and intermediate regimes of phase flow was substantiated. These characteristics being defined will allow determining more precisely the boundaries of the flow regimes and the methods of heat transfer prediction.

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