On the development of a model of coupled heat and moisture transfer in unsaturated soil

1992 ◽  
Vol 29 (6) ◽  
pp. 1107-1112 ◽  
Author(s):  
H. R. Thomas
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Unsaturated Soil ◽  
Moisture Transfer ◽  
Complex Model ◽  
Spatial Discretisation ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

The salient characteristics of a model of coupled heat and mass transfer in unsaturated soil are presented as a subset of a more complex model of the thermal–hydraulic–mechanical behaviour of unsaturated soil currently under development. Liquid and vapour flow continuity are considered separately before combining the two into a conservation of mass equation. Heat transfer by means of conduction, latent heat of vaporisation effects, and sensible heat transfer are included. A numerical simulation of the complete formulation is achieved via the use of the finite element method for spatial discretisation, with the time varying behaviour accommodated by a finite difference technique. An application of the model to the simulation of well-controlled laboratory experiments of heat and mass transfer in nondeforming medium sand is presented. Good correlation is obtained. Confidence in the approach developed is therefore achieved before proceeding to simulate the combination of the above flow processes with the deformation of engineered clay barriers. Key words : temperature, heat transfer, moisture flow, unsaturated soil, numerical model, experimental results, numerical simulation.

NUMERICAL SIMULATION FOR EFFECTS OF MICROCAPSULED PHASE CHANGE MATERIAL (MPCM) DISTRIBUTION ON HEAT AND MOISTURE TRANSFER IN POROUS TEXTILES

2009 ◽  
Vol 23 (03) ◽  
pp. 501-504 ◽  
Author(s):  
FENGZHI LI
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Materials ◽  
Moisture Transfer ◽  
Physical Parameters ◽  
Heat And Moisture Transfer ◽  
Numerical Predictions ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture ◽  
Transfer Properties

In recent years, the use of phase change materials (PCM) to improve heat and moisture transfer properties of clothing has gained considerable attention. The PCM distribution in the clothing impacts heat and moisture transfer properties of the clothing significantly. For describing the mechanisms of heat and moisture transfer in clothing with PCM and investigating the effect of the PCM distribution, a new dynamic model of coupled heat and moisture transfer in porous textiles with PCM was developed. The effect of water content on physical parameters of textiles and heat transfer with phase change in the PCM microcapsules were considered in the model. Meanwhile, the numerical predictions were compared with experimental data, and good agreement was observed between the two, indicating that the model was satisfactory. Also the effects of the PCM distribution on heat transfer in the textiles-PCM microcapsule composites were investigated by using the model.

Comparisons between Experiments and a Theoretical Model of Heat and Mass Transfer in Rotary Regenerators with Nonsorbing Matrices

1981 ◽  
Vol 103 (2) ◽  
pp. 189-195 ◽  
Author(s):  
J. G. van Leersum ◽  
C. W. Ambrose
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Mass Transfer ◽  
Theoretical Model ◽  
Heat And Mass Transfer ◽  
Equilibrium Model ◽  
Experimental Facility ◽  
Heat And Moisture ◽  
Good Agreement

A mathematical model of condensation, evaporation and heat transfer in a regenerator having a non sorbing matrix is derived. Good agreement between heat and moisture effectivities predicted by a simulation of the model, and corresponding results from an independently derived equilibrium model is shown for a particular case. Details of an experimental facility for testing the performance of a rotary regenerator are given, and a comparison between results obtained from the facility and those produced by the model are given.

Numerical Simulation of Heat and Moisture Transfer in System of Human-Clothing with Phase Change Materials-Environment

2011 ◽  
Vol 88-89 ◽  
pp. 470-474
Author(s):  
Feng Zhi Li ◽  
Peng Fei Wang ◽  
Yi Li
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Phase Change ◽  
Skin Temperature ◽  
Phase Change Materials ◽  
Moisture Transfer ◽  
Heat And Moisture Transfer ◽  
Model Predictions ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

A model of heat and moisture transfer in human-clothing with PCM-environment system is developed. In the model, the improved 25-node model is used for simulating human thermo- regulation, and the coupled heat and moisture model is applied to the PCM’s clothing. The model predictions and experimental data are compared. Also, the influences of the PCM on human skin temperature and sweat accumulation are predicted. The results are helpful to design of thermal functional clothing.

Numerical Simulation of Thermal Hydraulic Phenomena During Spray Injection Using Lagrangian and Eulerian Approaches

2018 ◽  
Author(s):  
TaeHyub Hong ◽  
JongWook Go ◽  
MiRo Seo
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Experimental Results ◽  
Dynamics Simulation ◽  
Severe Accident ◽  
Particle Model ◽  
Multiphase Model ◽  
Cfd Model

In this study, computational fluid dynamics simulation of gas-droplet flow in a spray injection in a THAI vessel is performed and the heat and mass transfer between the gas and the droplets are investigated. The purpose of the numerical simulation was validation of a CFD model to use in a hydrogen risk assessment in a containment building under severe accident conditions. The numerical simulation has to cover the physical phenomena that occur when spray water is injected downward into stationary gas in a large closed vessel. In order to model the two phase flow of the gas and droplets, two different modelling approaches are applied, one based on the Lagrangian approach and the other based on the Eulerian approach. In both approaches, the gas-droplet interactions are modelled using the two-way Lagrangian particle model and dispersed multiphase model to simulate gas-droplet interaction, two way coupling of momentum, and the heat and mass transfer between gas phase and droplet phase. For droplet heat and mass transfer, convective heat transfer and diffusion limited mass transfer are assumed. The calculated change in the temperature of the gas shows qualitative agreement with the experimental results but the gas temperature decrease was over predicted with both approaches. The calculated pressure shows good agreement with experimental results in both approaches. Both approaches also show similar prediction of temperature and pressure; therefore, they can both be applied to the containment analysis. The heat transfer coefficient in the gas-droplet heat transfer should be modified to be suitable for the spray flow. When considering that the spray system in the containment building is to be operated de-pressurized, the CFD model for the spray flow should be suitable for the thermal hydraulic analysis of the containment building.

Analysis of the Coupling of Heat and Moisture of the Soil under Circulating Action of Temperature

2012 ◽  
Vol 433-440 ◽  
pp. 6356-6362
Author(s):  
Dong Zhou ◽  
Xiao Duo Ou ◽  
Li Ming Wang ◽  
Guan Yong Yue
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Unsaturated Soil ◽  
Calculation Result ◽  
Maximum Error ◽  
Water Migration ◽  
Heat And Moisture ◽  
Test Result ◽  
Concentration Phenomenon

This article has used the equations of coupled heat-moisture anisothermal flow of the unsaturated soil, and conducted the numerical simulation coupling of heat and humidity by FLAC. By comparing the calculation result with the test result, it shows that the calculation result is close to the experiment result. The error is tending to be larger as the depth of the soil adds. The maximum error between the calculation and the experiment result is 1°C, and the smallest one is 0.1°C. Moreover due to the hysteresis of the heat transfer in the soil, the middle of the soil occurs temperature concentration phenomenon; Their trends of water migration variation are similar as the depth of the soil adds. The model of the coupling of heat and moisture is able to better simulate the change of heat and moisture of the soil under circulating action of temperature.

Ground-Coupled Heat and Moisture Transfer From Buildings: Part 2 — Application

2001 ◽  
Author(s):  
Michael P. Deru ◽  
Allan T. Kirkpatrick
Keyword(s):  
Heat Transfer ◽  
Moisture Transfer ◽  
Transfer Program ◽  
Soil Thermal Conductivity ◽  
Heat And Moisture Transfer ◽  
Conduction Model ◽  
Building Foundation ◽  
Dimensional Finite Element ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

Abstract In this paper the effects of moisture on the heat transfer from two basic types of building foundations, a slab-on-grade and a basement, are examined. A two-dimensional finite element heat and moisture transfer program is used to show the effects of precipitation, soil type, foundation insulation, water table depth, and freezing on the heat transfer from the building foundation. Comparisons are made with a simple heat conduction model to illustrate the dependency of the soil thermal conductivity on moisture content.

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