Numerical Simulation of Laminar Film Condensation over Vertical Plate with VOF Method [in Persian]
Abstract
In the present study, volume of fluid method in Open FOAM open source CFD package will be
extended to consider phase change phenomena due to condensation process. Both phases (liquid–
vapor) are incompressible and immiscible. Vapor phase is assumed in saturated temperature.
Interface between two phases is tracked with color function volume of fluid (CF-VOF) method.
Surface Tension is taken into consideration by Continuous Surface Force (CSF) model and mass
transfer occurring along interface is considered by Lee mass transfer model. Pressure-Velocity
coupling will be solved with PISO algorithm in the collocated grid. This solver is validated with
Stefan problem. In one dimensional Stefan problem, the distance of interface motion from cold
wall is compared with the analytical solution. Then condensate laminar liquid film flow over
vertical plate is simulated in the presence of gravity. Numerical result shows calculated film
thickness from numerical simulation is thinner than analytical solution. Also, it shows Nusselt
number is function of vapor specific heat which is neglected in existing correlations, therefore
analytical solution and experimental correlation should be modified to consider this effect on the
Nusselt Number.
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In this paper the principles of the FOAM C++ class library for continuum mechanics are outlined. The intention is to make it as easy as possible to develop reliable and efficient computational continuum mechanics (CCM) codes: this is achieved by making the top level syntax of the code as close as possible to conventional mathematical notation for tensors and partial differential equations. Object orientation techniques enable the creation of data types which closely mimic those of continuum mechanics, and the operator overloading possible in C++ allows normal mathematical symbols to be used for the basic operations. As an example, the implementation of various types of turbulence modelling in a FOAM computational uid-dynamics (CFD) code is discussed, and calculations performed on a standard test case, that of flow around an square prism, are presented. To demonstrate the exibility of the FOAM library, codes for solving structures and magneto-hydrodynamics are also presented w...
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combined with a variable density projection method to allow for
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the distance function formulation and the accuracy of the advection
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