Evaluation of the different definitions of the convective mass transfer coefficient for water evaporation into air

Steeman, Hendrik-Jan; T’Joen, Christophe; Belleghem, Marnix Van; Janssens, Arnold; Paepe, Michel De

doi:10.1016/j.ijheatmasstransfer.2009.01.047

Cited by 38 publications

(16 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The heat transfer coefficient is used to model the heat transfer (convective and radiant) between the environment and the surface of the porous material (walls, furniture…). The mass transfer coefficient models the moisture transfer between the air and the porous material [13]. They have to be determined indirectly through empirical or analytical correlations or from CFD calculations.…”

mentioning

confidence: 99%

Sensitivity analysis of CFD coupled non-isothermal heat and moisture modelling

Belleghem

Steeman

et al. 2010

Building and Environment

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 99%

Sensitivity analysis of CFD coupled non-isothermal heat and moisture modelling

Belleghem

Steeman

et al. 2010

Building and Environment

View full text Add to dashboard Cite

show abstract

“…The air and salt solution flows are assumed to be laminar and fully developed for the practical operating range of RAMEEs, therefore the convective heat and mass transfer coefficients for a given design are constant since the Nusselt number for a fully developed laminar flow is constant and is equal to 8.24 for a uniform heat flux in a parallel plate channel [26].Thus, U m /U is only a function of air channel thickness, th, (since for a constant Nusselt number, the convective heat and mass transfer coefficients change with th) the thickness of membrane, d, and the heat conductivity and mass conductivity of the membrane, k and k m . Therefore, for a given membrane and air channel thickness the ratio of U m to U is constant Therefore, for a given membrane and air channel thickness, the ratio of U m to U is constant provided that analogy between heat and mass transfer applies in the airstream and the flow configuration (counterflow in this paper) remains constant [27,28]. For other conditions and designs, the heat and mass transfer coefficients and the ratio of Um to U may change [27][28][29][30][31][32].…”

Section: System Parametersmentioning

confidence: 92%

Application of neural networks to predict the transient performance of a Run-Around Membrane Energy Exchanger for yearly non-stop operation

Akbari¹,

Simonson²,

Besant³

2012

International Journal of Heat and Mass Transfer

View full text Add to dashboard Cite

“…An internal coupling approach is used where both the porous material domain and the air domain are solved within the same solver. As a result there is no need for mass transfer coefficients to couple the mass transport between both domains [51]. In a more classical approach, HAM models use transfer coefficients to link the transport in the porous material with transport in the surrounding air.…”

Section: Experimental Validation Of a Cfd-ham Modelmentioning

confidence: 99%

“…This means that the airflow and by consequence the transfer coefficient depend on the air temperature and relative humidity. More details on this matter are found in [14,51]. Figure 9 shows a comparison of the measured and simulated relative humidity and temperature at three depths in the calcium silicate sample.…”

Section: Experimental Validation Of a Cfd-ham Modelmentioning

confidence: 99%

Benchmark experiments for moisture transfer modelling in air and porous materials

Belleghem

Steeman

Willockx

et al. 2011

Building and Environment

Self Cite

View full text Add to dashboard Cite

Abstract.The presence of hygroscopic materials has a large impact on the moisture balance of buildings. Nowadays, HAM (Heat, Air and Moisture) models are widely used to investigate the role of hygroscopic materials on the performance of buildings, i.e. on the building envelope, the indoor climate and valuable objects stored within the building. Recently, these HAM models are being coupled to CFD models to study the moisture exchange between air and porous materials on a local scale (microclimates), or to BES (Building Energy Simulation) models which focus on the interaction between air and porous materials at building level. Validation of these numerical codes is essential to gain confidence in the codes. However, available experimental data are rather scarce. This paper describes the design of a new test facility for humidity experiments. A dedicated AHU system is used to provide well-controlled air (constant temperature and RH) to an airtight and well-insulated room-size test chamber. In one of the walls of the chamber a calcium silicate sample is installed. A step in RH of the supply air is imposed. Temperature and RH of the supply air, the room air and on various depths inside the sample are continuously registered during the experiments. Two types of experiments were carried out to validate a coupled CFD-HAM model and a coupled BES-HAM model. The temperature outside the test chamber was controlled and there was no temperature difference imposed across the chamber walls. Comparing the models with the measured data gave satisfactory agreement.

show abstract

Evaluation of the different definitions of the convective mass transfer coefficient for water evaporation into air

Cited by 38 publications

References 19 publications

Sensitivity analysis of CFD coupled non-isothermal heat and moisture modelling

Sensitivity analysis of CFD coupled non-isothermal heat and moisture modelling

Application of neural networks to predict the transient performance of a Run-Around Membrane Energy Exchanger for yearly non-stop operation

Benchmark experiments for moisture transfer modelling in air and porous materials

Contact Info

Product

Resources

About