A Quasi-Three-Dimensional Approach to Predict the Performance of Steam Surface Condensers

1993 ◽  
Vol 115 (3) ◽  
pp. 213-220 ◽  
Author(s):  
C. Zhang ◽  
Y. Zhang
Keyword(s):  
Control Volume ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Governing Equations ◽  
Predictive Capability ◽  
Dimensional Approach ◽  
Shell Side ◽  
Flow And Heat Transfer ◽  
Surface Condenser ◽  
Flow Heat

A quasi-three-dimensional numerical procedure is proposed to simulate the fluid flow and heat transfer in the shell-side of steam surface condensers. The proposed procedure is applied to an experimental steam surface condenser to evaluate its predictive capability. The predicted results give good general agreement with the experimental data. The governing equations are solved in primitive variable form using a semi-implicit consistent control-volume formulation in which a segregated pressure correction linked algorithm is employed. The modeling of the geometries of condensers, including tube bundles and baffle plates, is carried out based on porous media concepts using flow, heat and mass transfer resistances.

Numerical Simulation of Different Types of Steam Surface Condensers

1991 ◽  
Vol 113 (2) ◽  
pp. 63-70 ◽  
Author(s):  
C. Zhang ◽  
A. C. M. Sousa ◽  
J. E. S. Venart
Keyword(s):  
Experimental Data ◽  
Control Volume ◽  
Numerical Procedure ◽  
Governing Equations ◽  
Transfer Processes ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Surface Condenser ◽  
Different Types ◽  
Good Agreement

A numerical procedure is developed to simulate the fluid flow and heat transfer processes in the shell-side of steam surface condensers. The governing equations are solved in primitive variable form using a semi-implicit consistent control-volume formulation in which a segregated pressure correction linked algorithm is employed. The procedure is applied to three different types of surface condenser. The numerical predictions are critically assessed by comparison to available experimental data for condensers, and in general, the solutions are in good agreement with the experimental data.

Numerical Modeling Using a Quasi-Three-Dimensional Procedure for Large Power Plant Condensers

1994 ◽  
Vol 116 (1) ◽  
pp. 180-188 ◽  
Author(s):  
C. Zhang
Keyword(s):  
Power Plant ◽  
Mass Fraction ◽  
Tube Bundle ◽  
Control Volume ◽  
Three Dimensional ◽  
Predictive Capability ◽  
Large Power ◽  
Operational Conditions ◽  
Proposed Model ◽  
Flow Heat

A quasi-three-dimensional numerical model is proposed to predict the performance of large power plant condensers. The proposed model is applied to a 350 MW power plant condenser under two different loading and operational conditions to demonstrate its predictive capability. The predictions are compared with the experimental data. The comparison is favorable. The equations governing the conservation of mass, momentum, and air mass fraction are solved in primitive variable form using a semi-implicit consistent control-volume formulation in which a segregated pressure correction linked algorithm is employed. The modeling of the condenser geometry, including the tube bundle and baffle plates, is carried out based on a porous media concept using applicable flow, heat, and mass transfer resistances.

A mixed finite element/control volume model of wind-driven circulation in lakes

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Victor Podsechin
Keyword(s):  
Control Volume ◽  
Mixed Finite Element ◽  
Surface Wind ◽  
Three Dimensional ◽  
Circulation Model ◽  
Hydrodynamic Equations ◽  
Governing Equations ◽  
Near Surface ◽  
Stream Functions ◽  
Surface Wind Field

AbstractA three-dimensional numerical circulation model is described. The model is based on non-linear hydrodynamic equations, modified according to hydrostatic and Boussinesq approximations. A space-splitting scheme is used for numerical approximations of governing equations. The simple hypothesis on elliptic stream functions shape is utilized to reconstruct the near-surface wind field. The calculated currents correspond reasonably well with observed velocities in different locations lake-wide.

Buoyancy Effect on Developing Turbulent Flow and Heat Transfer in a Helical Pipe With Finite Pitch

2000 ◽  
Author(s):  
B. Zheng ◽  
C. X. Lin ◽  
M. A. Ebadian
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Control Volume ◽  
Three Dimensional ◽  
Boussinesq Approximation ◽  
Buoyancy Effect ◽  
Constant Wall Temperature ◽  
Flow And Heat Transfer ◽  
Helical Pipe ◽  
Volume Method

Abstract Numerical modeling was performed to investigate the buoyancy effect on developing turbulent flow and the heat transfer characteristics of saturated water in a helical pipe with finite pitch. The renormalization group (RNG) κ–ε model was used to account for the turbulent flow and heat transfer in the helical pipe at a constant wall temperature with or without buoyancy force effect. A control volume method with second-order accuracy was used to numerically solve the three-dimensional full elliptic governing equations for this problem. The O-type nonuniform structured grid system was adopted to discretize the computation domain. The Boussinesq approximation was applied to deal with the buoyancy. This study explored the influence of buoyancy on the developing heat transfer along the helical pipe. Based on the results of this research, the velocity, temperature, and Nusselt number are presented graphically and analyzed.

Fluid Flow and Heat Transfer Over a Three-Dimensional Spherical Object in a Pipe

1998 ◽  
Vol 120 (4) ◽  
pp. 985-990 ◽  
Author(s):  
N. Shahcheraghi ◽  
H. A. Dwyer
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Pipe Wall ◽  
Three Dimensional ◽  
Governing Equations ◽  
Sphere Surface ◽  
Spherical Object ◽  
Number Range ◽  
Flow And Heat Transfer ◽  
Grid Scheme

An incompressible viscous fluid flow with heat transfer over a spherical object inside a pipe is considered. The flow is made three-dimensional by an eccentric positioning of the sphere inside the pipe. The governing equations are solved by a numerical method which uses a finite volume formulation in a generalized body fitted coordinate system. An overset (Chimera) grid scheme is used to resolve the two geometries of the pipe and sphere. The results are compared to those of an external flow over a sphere, and the code is validated using such results in the intermediate Reynolds number range. The blockage effects are analyzed through evaluation of lift, drag, and heat transfer rate over the sphere. Also the change in the shear stress pattern is examined through evaluation of the local friction factor on a pipe wall and sphere surface.

Simulation of Flow and Heat Transfer in Triangular Cross-Sectional Solar-Assisted Air Heater

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Rajneesh Kumar ◽  
Anoop Kumar ◽  
Varun Goel
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Roughness Parameter ◽  
Solar Air Heater ◽  
Governing Equations ◽  
Cross Sectional ◽  
Air Heater ◽  
Flow And Heat Transfer ◽  
Finite Volume Approach ◽  
D Values

The ribbed three-dimensional solar air heater (SAH) model is numerically investigated to estimate flow and heat transfer through it. The numerical analysis is based on finite volume approach, and the set of flow governing equations has been solved to determine the heat transfer and flow field through the SAH. For detailed analysis, rib chamfer height ratio (e′/e) and rib aspect ratio (e/w), two innovative parameters, have been created and considered along with the commonly used roughness parameter, i.e., relative roughness height, e/D. The parameters e′/e, e/w, and e/D are varied from 0.0 to 1, 0.1 to 1.5, and 0.18 to 0.043, respectively, but the value of P/e is kept constant for the entire investigation at 12. A good match is seen in Nusselt number (Nu) and friction factor (f) by comparing the predicted results with the experimental ones. With the variation of roughness parameters, distinguishable change in Nu and f is obtained. The highest value of thermohydraulic performance parameter (TPP) observed is 2.08 for P/e, e′/e, e/w, and e/D values of 12, 0.75, 1.5, and 0.043, respectively, at Re of 17,100. The developed generalized equation for Nu and f has shown acceptable percentage deviation under the studied range of parameters.

scholarly journals A Numerical Study of Three-Dimensional Flow Separation and Wake Development in an Axial Compressor Rotor

1984 ◽  
Author(s):  
C. Hah
Keyword(s):  
Viscous Flow ◽  
Turbulent Flows ◽  
Numerical Study ◽  
Control Volume ◽  
Turbulent Transport ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Computational Procedure ◽  
Navier Stokes Equation ◽  
Compressor Rotor

A computational procedure based on the compressible Reynolds-averaged Navier-Stokes equation has been developed for the viscous flow through an isolated compressor rotor. The numerical scheme is based on fully conservative control volume formulation and solves various conservation equations in fully elliptic form on the rotating coordinates fixed on the rotor. An algebraic Reynolds stress model is used to describe the turbulent transport terms. The numerical procedure has been applied to predict three-dimensional turbulent flows through two different isolated compressor rotors. The detailed quantitative comparisons with two sets of well-documented data show that the developed computational procedure predicts the viscous flow development over the blading and in the wake with the accuracy satisfactory for most engineering purposes; the computer code can be used for the guidance of advanced rotor design.

A Mathematical Model for Optimizing the Structure of a Flat Micro Heat Pipe with Fiber Wick

2011 ◽  
Vol 187 ◽  
pp. 261-265
Author(s):  
Tian Han ◽  
Xiao Wei Liu ◽  
Rui Zhang ◽  
Chao Wang
Keyword(s):  
Mathematical Model ◽  
Contact Angle ◽  
Heat Pipe ◽  
Control Volume ◽  
Three Dimensional ◽  
Heat Conducting ◽  
Governing Equations ◽  
Micro Heat Pipe ◽  
Changing Rate

A three-dimensional mathematical model is developed for a kind of micro heat pipe with fiber wick. The effects of phase changing, the contact angle, gravity, and heat conducting between the fibers are accounted in the model. The governing equations are formulated in the control volume and calculated by iteration. The calculated results of the model present the velocity of the working material and the phase changing rate of the liquid. The structure of the micro heat pipe is optimized by the calculated results of the model and the two levels of fibers are enough for this kind of flat micro heat pipe.

Insight into rime ice accretion on an aircraft wing and corresponding effects on aerodynamic performance

2016 ◽  
Vol 120 (1229) ◽  
pp. 1101-1122 ◽  
Author(s):  
Y. Cao ◽  
J. Huang ◽  
Z. Xu ◽  
J. Yin
Keyword(s):  
Collection Efficiency ◽  
Control Volume ◽  
Fluid Model ◽  
Three Dimensional ◽  
Wing Surface ◽  
Ice Accretion ◽  
Governing Equations ◽  
Aircraft Wing ◽  
Two Phase ◽  
Environment Temperature

ABSTRACTA method based on the Eulerian two-phase flow theory to numerically simulate three-dimensional rime ice accretions on an aircraft wing is presented in this paper. The governing equations for supercooled droplet motion under Eulerian framework are established using the droplet pseudo-fluid model. A permeable wall boundary condition is proposed to simulate the phenomenon of droplets impinging on the wing in solving the governing equations for droplets. The local droplet collection efficiency is readily obtained from the droplet flowfield solution in the control volume adjacent to the wing surface. The rime ice accretion can be simulated under the assumption that the droplets freeze immediately as they impinge on the wing surface since the environment temperature is low enough (typically below –15°C). A method to build the ice shape is proposed based on the assumption that ice grows in the direction normal to the wing surface. The rime ice accretion on a GLC-305 swept wing model under some specific conditions has been simulated to validate the present method. Furthermore, different flight conditions, namely, different angles of attack and different angles of sideslip, have been dealt with to investigate their effects on rime ice accretion as well as the corresponding aerodynamic effects.

A Navier-Stokes Analysis of Three-Dimensional Turbulent Flows Inside Turbine Blade Rows at Design and Off-Design Conditions

1984 ◽  
Vol 106 (2) ◽  
pp. 421-429 ◽  
Author(s):  
C. Hah
Keyword(s):  
Turbulent Flows ◽  
Turbine Blade ◽  
Numerical Scheme ◽  
Control Volume ◽  
Three Dimensional ◽  
Leading Edge ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Governing Equations ◽  
Navier Stokes Equation

A numerical scheme based on the compressible Navier-Stokes equation has been developed for three-dimensional turbulent flows inside turbine blade rows. The numerical scheme is based on a fully conservative control volume formulation and solves the governing equations in fully elliptic form. Higher order discretizations are used for the convection term to reduce the numerical diffusion. An algebraic Reynolds stress model modified for the effects of the streamline curvature and the rotation is used for the closure of the governing equations. General coordinate transformations are used to represent the complex blade geometry accurately, and a grid generation technique based on elliptic partial differential equations is employed. Comparisons with the experimental data show that various complex three-dimensional viscous flow phenomena (three-dimensional flow separation near the leading edge, formation of the horseshoe vortex, etc.) are well predicted with the present method.

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