Numerical Simulation of Condensation on a Capillary Grooved Structure

2000 ◽  
Author(s):  
Yuwen Zhang ◽  
Amir Faghri
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Drop ◽  
Governing Equations ◽  
Additional Source ◽  
Vof Model ◽  
Effects Of Temperature ◽  
Energy Equations ◽  
Fin Thickness ◽  
Liquid And Vapor Phases

Abstract Condensation in a capillary grooved structure is investigated using the Volume of Fluid (VOF) model. The governing equations are written in a generalized form and are applicable to both liquid and vapor phases. Condensation on the fin top and at the meniscus is modeled by introducing additional source terms in the continuity, VOF, and energy equations. The effects of temperature drop, contact angle, surface tension, and fin thickness on the condensation heat transfer are investigated.

Combined Effects of Temperature and Velocity Jump on the Heat Transfer, Fluid Flow, and Entropy Generation Over a Single Rotating Disk

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
A. Arikoglu ◽  
G. Komurgoz ◽  
I. Ozkol ◽  
A. Y. Gunes
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Entropy Generation ◽  
Rotating Disk ◽  
Heat Transfer Fluid ◽  
Combined Effects ◽  
Jump Conditions ◽  
Governing Equations ◽  
Velocity Jump ◽  
Effects Of Temperature

The present work examines the effects of temperature and velocity jump conditions on heat transfer, fluid flow, and entropy generation. As the physical model, the axially symmetrical steady flow of a Newtonian ambient fluid over a single rotating disk is chosen. The related nonlinear governing equations for flow and thermal fields are reduced to ordinary differential equations by applying so-called classical approach, which was first introduced by von Karman. Instead of a numerical method, a recently developed popular semi numerical-analytical technique; differential transform method is employed to solve the reduced governing equations under the assumptions of velocity and thermal jump conditions on the disk surface. The combined effects of the velocity slip and temperature jump on the thermal and flow fields are investigated in great detail for different values of the nondimensional field parameters. In order to evaluate the efficiency of such rotating fluidic system, the entropy generation equation is derived and nondimensionalized. Additionally, special attention has been given to entropy generation, its characteristic and dependency on various parameters, i.e., group parameter, Kn and Re numbers, etc. It is observed that thermal and velocity jump strongly reduce the magnitude of entropy generation throughout the flow domain. As a result, the efficiency of the related physical system increases. A noticeable objective of this study is to give an open form solution of nonlinear field equations. The reduced recurative form of the governing equations presented gives the reader an opportunity to see the solution in open series form.

scholarly journals Experimental and Parametric Study of Extended Fins In The Optimization of Internal Combustion Engine Cooling Using CFD

2012 ◽  
pp. 81-90
Author(s):  
J.Ajay Paul ◽  
Sagar Chavan Vijay ◽  
U. Magarajan ◽  
R.Thundil Karuppa Raj
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Internal Combustion Engine ◽  
Numerical Simulations ◽  
Parametric Study ◽  
Combustion Engine ◽  
Heat Transfer Characteristics ◽  
Engine Cooling ◽  
Fin Thickness ◽  
Annular Fins

In this experiment the single cylinder air cooled engines was assumed to be a set of annular fins mounted on a cylinder. Numerical simulations were carried out to determine the heat transfer characteristics of different fin parameters namely, number of fins, fin thickness at varying air velocities. A cylinder with a single fin mounted on it was tested experimentally. The numerical simulation of the same setup was done using CFD. The results validated with close accuracy with the experimental results. Cylinders with fins of 4 mm and 6 mm thickness were simulated for 1, 3, 4 &6 fin configurations.

Coupled Numerical Simulation of Process in Rheocasting-Rolling for Semi-Solid Magnesium Alloy Used By Slope

2010 ◽  
Vol 89-91 ◽  
pp. 681-686 ◽  
Author(s):  
Ying Zhang ◽  
Shui Sheng Xie ◽  
Mao Peng Geng ◽  
Hong Min Guo ◽  
Hai Bo Zhao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Magnesium Alloy ◽  
Technical Parameter ◽  
The Finite Element Method ◽  
Pouring Temperature ◽  
Flow And Heat Transfer ◽  
Lean Angle ◽  
Semi Solid ◽  
Energy Equations

By the finite element method, the N-S momentum, energy equations and continuum equations, etc. which describe the fluid flow and heat transfer in the slope of the rheocasting-rolling for Semi-solid Magnesium Alloy were computed. The influence of the different slope parameters( pouring temperature, length of slope, lean angle)on the metallographic structure of semi-solid magnesium alloy was analyzed. The simulative results can provide effective data to confirm optimized slope size and technical parameter.

scholarly journals Numerical simulation of coupeld heat transfer through a concrete hollow brick

2019 ◽  
Vol 286 ◽  
pp. 08004
Author(s):  
B. Jamal ◽  
M. Boukendil ◽  
A. Abdelbaki ◽  
Z. Zrikem
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Fluid Flow ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Simple Algorithm ◽  
Governing Equations ◽  
Coupled Heat Transfer ◽  
Hollow Brick ◽  
Finite Volume Approach

The present study aims to investigate coupled heat transfer by natural convection and conduction through a concrete hollow brick. The governing equations for conservation of mass, momentum and energy are discretized by the finite volume approach and solved by the SIMPLE algorithm. The numerical simulations were conducted to investigate the effect of Rayleigh number (103≤ Ra ≤ 107) on the heat transfer and fluid flow within the structure.

Numerical Simulation of Liquefied Natural Gas in Rib-Tube

2013 ◽  
Vol 483 ◽  
pp. 162-165
Author(s):  
Su Hou De ◽  
Zhang Yu Fu ◽  
Ji Yong Che ◽  
Xiao Long Wen
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Fluid Flow ◽  
Heat Exchange ◽  
Natural Gas ◽  
Liquefied Natural Gas ◽  
Dispersed Phase ◽  
Wall Function ◽  
Governing Equations ◽  
Set Up

The flow of liquefied natural gas (LNG) which was coupled between heat transfer and fluid-flow in rib-tube was studied in this paper. Based on theoretical analysis, the model and wall-function were chosen to simulate the flow field of rib-tube, and the multiphase flow was described by the mixture model, in which the dispersed phase was defined by different velocity. In addtion, self-defining functions were used and governing equations were set up to solve the dispersed phase, and the result were compared with the experiment. The process of fluid-flow and heat exchange on rib-tube was simulated, and the contours of temperature, pressure, velocity, gas fraction were obtained, which showed that, the parameters of above changed when the temperature was rising and the LNG evaporating along the rib-tube, and a mixed process existed in the middle of the heat tube.

scholarly journals Computational investigation on heat transfer augmentation of a circular tube with novel hybrid ribs

2021 ◽  
Vol 321 ◽  
pp. 04012
Author(s):  
Suvanjan Bhattacharyya ◽  
Devendra Kumar Vishwakarma ◽  
Sanghati Roy ◽  
Kunal Dey ◽  
Ali Cemal Benim ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Computational Investigation ◽  
Governing Equations ◽  
Ansys Fluent ◽  
Magnetic Nanofluid ◽  
Heat Transfer Augmentation ◽  
Flow Through ◽  
Energy Equations ◽  
Exchanger Tube

Present study reports a computational investigation on heat transfer and pressure drop characteristics for flow through a heat exchanger tube fitted with novel hybrid ribs by using magnetic nanofluid (Fe3O4). Effects of different rib geometry on heat transfer and pressure drop characteristics have been investigated for Reynolds number ranging from 3 000 to 22 000. Until now, there is little information available in the literature on the method of quantifying the effect of forced convection on the heat transfer and pressure drop of hybrid rib (HR) inserts by using magnetic nanofluid (MNF). The transition SST models along with governing equations (continuity, momentum, and energy equations) are numerically solved with ANSYS Fluent 19.2. The simulation results are validated with established correlations and excellent agreement was found. Heat transfer coefficient is more in combined arrangement (HR and MNF) compared to acting alone arrangement (only MNF).

Structural Optimized Design about New Heat Exchanger of Air-Condition

2011 ◽  
Vol 71-78 ◽  
pp. 2298-2302
Author(s):  
Rui Wang ◽  
Yi Chun Wang ◽  
Chao Qing Feng ◽  
Huo Ming Zhan ◽  
Hua Jun Li
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Theoretical Basis ◽  
Structural Parameters ◽  
Optimized Design ◽  
Fin Thickness

The heat exchanger model of air-condition is deal with the reasonable simplification and in order to take numerical simulation about heat exchange in air side, the Fluent is adopt. Optimized design include four aspects: fin thickness, fin height, distance between two fins and the shape of ripple fins. After the numerical simulation, the best structural parameters of fin are received. It can provide a theoretical basis for design and research. After this optimized design, the exchanger can improve the heat transfer ability and save many materials.

scholarly journals Thermal Radiation on Mixed Convective Flow in a Porous Cavity: Numerical Simulation

2018 ◽  
Vol 7 (4) ◽  
pp. 253-261 ◽  
Author(s):  
B.M.D. Hidayathulla Khan ◽  
V. Ramachandra Prasad ◽  
R. Bhuvana Vijaya
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Convective Flow ◽  
Darcy Number ◽  
Uniform Temperature ◽  
Governing Equations ◽  
Square Enclosure ◽  
Vertical Walls ◽  
Mixed Convective Flow ◽  
Marker And Cell Method

Abstract In this paper, the influence of mixed convection in a porous square enclosure under the effect of radiation is numerically examined. The top and bottom walls are maintained at uniform temperature θc while some portion of the vertical walls is partially heated with temperature θh and rest of the vertical walls are thermally insulated, with θh > θc. The non-dimensional governing equations are solved by MAC (Marker and Cell) method. The effect of various parameters (thermal Grashof number, Darcy number, Prandtl number, Reynolds number) on flow patterns and heat transfer has been presented.

300 MW Coal Tangential Boiler Furnace Numerical Simulation

2014 ◽  
Vol 597 ◽  
pp. 484-487
Author(s):  
Hong Xian Liu ◽  
Bin Xia Li
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Gas Phase ◽  
Governing Equations ◽  
Boiler Furnace ◽  
Temperature Deviation ◽  
Calculation Results ◽  
Simplec Algorithm ◽  
Flow Heat

By using the computational fluid dynamics software Fluent and the choice of the reasonable mathematical model, the flow, heat transfer and combustion are simulated in a 300 MW tangential firing boiler furnace. In the process of numerical simulation in the furnace, the gas phase turbulent flow usesRealizable model for both sides and solves the governing equations using SIMPLEC algorithm. Calculation results show that the highest temperature in the furnace is in the burner area,the whole furnace space rotates flow field, residual rotation still exists in the exit of the furnace, and the smoke temperature deviation causes in the residual rotation of furnace exit.

Enhancement of Gas Enthalpy-Radiation Conversion by Utilizing Multilayer Open-Cellular Porous Materials

2010 ◽  
Author(s):  
Preecha Khantikomol ◽  
Shinichi Saito ◽  
Takehiko Yokomine
Keyword(s):  
Heat Transfer ◽  
Porous Materials ◽  
Porous Layer ◽  
Porous Plate ◽  
Temperature Drop ◽  
Maximum Temperature ◽  
Gas Temperature ◽  
Energy Equations ◽  
Radiation Conversion ◽  
Porous Converter

Multilayer porous gas enthalpy-radiation converter consisting of two porous plates divided by free space is proposed to enhance the performance of single layer porous converter. The energy equations of the gas and the solid phases are employed by using separate energy equations model, and the convective heat transfer between the two phases based on an empirical volumetric heat transfer coefficient proposed by Kamiuto and San San Yee is estimated. The P1 approximation method is employed to evaluate the radiation of transfer equation. Results show that high porosity and PPI (pores per inch) are effective to raise the gas enthalpy-radiation conversion. The upstream porous layer should be lower in porosity and PPI than the downstream porous layer. To increase the temperature drop across the porous gas enthalpy-radiation converter, the inlet gas temperature should be high and the upstream radiation temperature should be low. To obtain maximum temperature drop across the multilayer porous converter, both layers should be made of pure absorbing porous materials. In case the upstream radiation temperature exceeds an inlet gas temperature, however, use of pure scattering porous plate on the upstream side and pure absorbing porous plate on the downstream side will obtain the maximum temperature drop across the converter. The validity of the predicted numerical model also has been confirmed by the experimental data.

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