scholarly journals Heat Transfer Phenomena in Laminar Wavy Falling Films: Thermal Entry Length, Thermal-Capillary Metastable Structures, Thermal-Capillary Breakdown

10.5772/13652 ◽  
2011 ◽  
Author(s):  
Viacheslav V. ◽  
Reinhold Kneer
Keyword(s):  
Heat Transfer ◽  
Entry Length ◽  
Falling Films ◽  
Metastable Structures

Thermal Entry Length and Heat Transfer Phenomena in Laminar Wavy Falling Films

2009 ◽  
Vol 21 (S1) ◽  
pp. 215-220 ◽  
Author(s):  
Viacheslav V. Lel ◽  
Faruk Al-Sibai ◽  
Reinhold Kneer
Keyword(s):  
Heat Transfer ◽  
Entry Length ◽  
Falling Films

EXPERIMENTAL STUDY OF HEAT TRANSFER IN LAMINAR FALLING FILMS AT HIGH PRANDTL NUMBERS

2000 ◽  
Vol 12 (3-4) ◽  
pp. 16
Author(s):  
Kemal Tuzla ◽  
Thomas R. Palmer ◽  
John C. Chen
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Falling Films ◽  
Prandtl Numbers

scholarly journals Influence of Macroscopic Wall Structures on the Fluid Flow and Heat Transfer in Fixed Bed Reactors with Small Tube to Particle Diameter Ratio

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 689
Author(s):  
Thomas Eppinger ◽  
Nico Jurtz ◽  
Matthias Kraume
Keyword(s):  
Heat Transfer ◽  
Fixed Bed ◽  
Particle Diameter ◽  
Diameter Ratio ◽  
Spherical Particles ◽  
Reactor Wall ◽  
Entry Length ◽  
Fixed Bed Reactors ◽  
Wall Structures ◽  
Small Tube

Fixed bed reactors are widely used in the chemical, nuclear and process industry. Due to the solid particle arrangement and its resulting non-homogeneous radial void fraction distribution, the heat transfer of this reactor type is inhibited, especially for fixed bed reactors with a small tube to particle diameter ratio. This work shows that, based on three-dimensional particle-resolved discrete element method (DEM) computational fluid dynamics (CFD) simulations, it is possible to reduce the maldistribution of mono-dispersed spherical particles near the reactor wall by the use of macroscopic wall structures. As a result, the lateral convection is significantly increased leading to a better radial heat transfer. This is investigated for different macroscopic wall structures, different air flow rates (Reynolds number Re = 16 ...16,000) and a variation of tube to particle diameter ratios (2.8, 4.8, 6.8, 8.8). An increase of the radial velocity of up to 40%, a reduction of the thermal entry length of 66% and an overall heat transfer increase of up to 120% are found.

Heat transfer characteristics of obliquely dispensed evaporating falling films on an elliptic tube

2019 ◽  
Vol 132 ◽  
pp. 238-248 ◽  
Author(s):  
Yee-Ting Lee ◽  
Sihui Hong ◽  
Chaobin Dang ◽  
Liang-Han Chien ◽  
Li-Wang Chang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Falling Films ◽  
Transfer Characteristics

Heat transfer in turbulent falling films

1995 ◽  
Vol 18 (3) ◽  
pp. 171-177 ◽  
Author(s):  
Reiner Numrich
Keyword(s):  
Heat Transfer ◽  
Falling Films

Mass and heat transfer entry length for power law fluids in cylindrical geometry

1981 ◽  
Vol 8 (5) ◽  
pp. 425-436 ◽  
Author(s):  
R.D. Tonini ◽  
N.O. Lemcoff
Keyword(s):  
Heat Transfer ◽  
Power Law ◽  
Cylindrical Geometry ◽  
Entry Length ◽  
Power Law Fluids ◽  
Mass And Heat Transfer

Prediction Methods for Entry Length Heat Transfer by Combined Laminar Convection in Horizontal Tubes

1982 ◽  
Vol 196 (1) ◽  
pp. 409-415 ◽  
Author(s):  
P H G Allen ◽  
O Szpiro ◽  
M W Collins
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Laminar Flow ◽  
Prediction Methods ◽  
Entry Length ◽  
Horizontal Tubes ◽  
Temperature Distributions ◽  
Constant Rate ◽  
Full Solution ◽  
Laminar Convection

Numerical prediction methods for calculating velocity and temperature distributions in heated ducts can be made accurately but are time consuming. The paper shows possible simplifications, including the neglect of the buoyancy term, and the resultant accuracy attained. The case studied is for laminar flow, entry length heat transfer in horizontal tubes with constant rate heat flux. Comparison is made between experimental results, a full solution and an approximation based on a series of truncated versions of the fully developed temperature profile. Calculations are made both with and without variation of thermophysical properties with temperature.

Three-Dimensional Numerical Simulation on the Laminar Flow and Heat Transfer in Four Basic Fins of Plate-Fin Heat Exchangers

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Yinhai Zhu ◽  
Yanzhong Li
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Heat Exchangers ◽  
Flow Direction ◽  
Three Dimensional ◽  
Entry Length ◽  
Flow And Heat Transfer ◽  
F Factor ◽  
The One ◽  
Data Reduction Method

In this paper, four basic fins of the plate-fin heat exchangers, rectangular plain fin, strip offset fin, perforated fin, and wavy fin, are modeled and simulated by taking account of fin thickness, thermal entry effect, and end effect. Three-dimensional numerical simulations on the flow and heat transfer in the four fins are investigated and carried out at laminar flow regime. Validity of the modeling technique is verified by comparing computational results with both corresponding experimental data and three empirical correlations from literatures. Global average Colburn factor (j factor) and friction factor (f factor) and their local 1D streamwise-average distributions along the fins are presented by introducing data reduction method. The heat transfer behaviors in both the developing and developed regions are analyzed by examining variations of the local Nusselt number along the flow direction. It is found that the thermal entry length of the four fins might be expressed in the format of Le=c1 Rec2 Pr Dh, which has the same form as the one in a circular tube.

B307 DEVELOPMENT OF STEAM GENERATOR USING FALLING FILMS ON HEAT TRANSFER TUBES(Multiphase Flow-2)

2009 ◽  
Vol 2009.3 (0) ◽  
pp. _3-97_-_3-102_
Author(s):  
Shuichi UMEZAWA ◽  
Haruo AMARI ◽  
Takayuki TSUJII ◽  
Kenji WATANABE
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Steam Generator ◽  
Falling Films
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