I just want ask if any one is working on CFD simulation of gas boiler with two phase case? And what do you to think the best CFD package for Two phase cases?
Could I know which CFD packages you have to deal with this kind of problem on the availability of cfd package a your side, i am able to suggest you the best out of them.
However ANSYS fluent is a good alternate for dealing this kind of flow and easily available in academic as well as commercial licence.
I am trying to simulate the Domestic Gas boiler, which will have boiling of water; (that makes it multiphase CFD simulation), I hope that will help for better recommendation. Thank you in advance for you valuable recommendation.
The physical mechanism which is recorded in the kinetic theory for the description of real phenomena, connected with the movement and interaction of structural elements of a many-particle system in question. Rather simple this system is sparse gas, in which the structural elements in the form of molecules are identified by their chemical properties, and the interaction can be regarded as a collision when the thermal random motion. This model allows to describe both equilibrium and non-equilibrium properties.
2. Курлапов Л.И., Спицын А.А. Кинетическое описание теплопроводности различных веществ. // «Высокие технологии – залог устойчивого развития»: Труды Международной научной конференции» – Алматы: КазНТУ им. К.И. Сатпаева, 2011. – 434 с. (ISBN 978-601-228-312-9) - Стр. 186-190.
The basic receptions of the description are applicable (applied) and to dense gases in view of that structural elements in them will be not only molecules, but also clusters . Existence of clusters demands to model any gas a multicomponent mixtures: molecular cluster a mix. At such description there are essential those unsolved problems which have remained at the description of rarefied gases. Such problems, in particular, are connected to the description of heat conductivity. A phenomenological relation for the description of heat conductivity is law Fourier which has the same kind, as well as laws for other transport processes: the superficial density of a stream of extensive property is proportional to a gradient of the appropriate intensive property. In such simple kind this law is applicable only to the motionless media and for a case when non uniformity of system is determined only by a gradient of temperature. As follows from experiments and with the kinetic theory in gases the gradient of temperature results in occurrence of a stream of particles of a diffusion nature (an irreversible flow), and in the closed devices - and to a stream of a convertible nature It creates a problem of the theoretical description of coexistence both conductive, and convective components in an observably (flow) stream or allocation of only irreversible stream of energy in experiment that is proved to apply Fourier law to gas as to the motionless continuous environment. In molecular cluster mixtures this problem is aggravated with evolution of cluster structure that is accompanied by changeability of number of structural elements both separate cluster subcomponents and all gas. Conditions of mechanical equilibrium are not carried out that also does not allow to apply and existing thermodynamics of irreversible processes.
Other problem is connected to microscopic interpretation of a thermal current in the kinetic theory in which well work ways of calculation of number of the particles crossing a control platform and carry by them of a molecular attribute as extensive parameter falling one particle. As follows from the first Law of thermodynamics, heat is not function of a state, therefore it is impossible to determine the molecular attribute appropriate to heat. In molecular cluster mixtures still it is necessary to take into account transformations of energy which accompany with processes of formation and decays of clusters at and evolutions of cluster structure.
In the present report the way of the description in which the named problems of the kinetic description of heat conductivity of molecular cluster mixtures are shown to a minimum is applied. Calculations on temperature dependence of heat conductivity will well be coordinated to the existing help data.
The convergence problem in COMSOL depends on whether you use direct solver or iterative solver. In my experience, for fluid flow problem, iterative approach fails most of the time.
CD-adapco's STAR-CD and STAR-CCM+ seem to be well established for multiphase flows at component scale.
References:
Ustinenko, V. et al., Validation of CFD-BWR, a new two-phase computational fluid dynamics model for boiling water reactor analysis. Nuc. Eng. and Des. 238 (2008) 660-670
Ioilev A., et al., Advances in the modeling of cladding heat transfer and critical heat flux in boiling water reactors fuel assemblies. Proceedings of NURETH-12, 2007
Tentner A., et al., Development and validation of an extended two-phase computational fluid dynamics model for the analysis of boiling flow in reactor fuel assemblies. Proceedings of ICAPP 2007.