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Water condensation and two-phase flow modeling for a plate heat exchanger channel

In English

Författare

Summary, in English

There are water vapour condensation and two-phase flow in plate heat exchangers when they are used as condensers. Water phase change and flow dynamics modelling is an important but complicated task due to large change in water physical/transport properties across the water liquid-vapour interface boundary. In particular, singular-link behaviour in governing equations is present due to the large step change in the density when computational fluid dynamics (CFD) is employed. Conventional methods using ensemble averaged parameters such as void fraction are impossible to be applied to cases where high-resolution calculations and detailed analysis are required. In this study, a CFD approach is employed to model water vapour condensation and two-phase flow in a channel relevant for plate heat exchanger parallel plates. The developed model is based on the governing equations which are directly solved for the entire single- and two-phase fields. The water phase change and two-phase flow are treated by employing a water liquid-phase fraction factor based on the total enthalpy in each computational cell. The factor is defined as the ratio of the total enthalpy differential to the latent heat of condensation. The thermal-physical properties, such as density, viscosity and conductivity of the two-phase region, are calculated and updated based on the calculated value of the liquid-phase fraction factor until a converged result is reached. It is concluded that, among others, the inlet vapour velocity has significant effects on the water phase change and two-phase flow in the channel, in terms of liquid-water fraction factor distribution.

Avdelning/ar

Publiceringsår

2008

Språk

Engelska

Sidor

349-354

Publikation/Tidskrift/Serie

Proceedings of the ASME International Mechanical Engineering Congress and Exposition 2007, vol 8, pts A and B - Heat Transfer, Fluid Flows and Thermal Systems

Dokumenttyp

Konferensbidrag

Förlag

American Society Of Mechanical Engineers (ASME)

Ämne

  • Energy Engineering

Nyckelord

  • analysis
  • model
  • two-phase flow
  • water
  • condensation

Conference name

ASME International Mechanical Engineering Congress and Exposition, 2007

Conference date

2007-11-11 - 2007-11-15

Conference place

Seattle, Wa, United States

Status

Published