numerical simulation

CFD simulations were conducted to assess turbulent forced convection heat transfer and pressure drop through a ventilation channel using a stack of panels with different ridge configurations containing Phase Change Material (PCM). First, an experimental rig using an existing commercial panel provided by a PCM manufacturer validates the model simulated in Ansys FLUENT. After that, 3D simulations with different designs were tested until the optimum configuration in terms of heat transfer and pressure drop was achieved.

Typical heat sources in indoor environments include humans, electrical devices, and computers. The number of such sources in operating room environments is even higher due to the presence of surgical staff members and medical equipment. The exchange of thermal energy between indoor surfaces and air is usually modelled by considering contributions from both radiation and convection. Complete heat transfer simulations in indoor environments are normally difficult since radiation models have a tendency to generate numerical instability and, hence, problems with convergent solutions.

The indoor fire induced by gas leakages can cause a lot of property losses and fatalities. One of the  primary fire reasons is the explosion caused by the leaked gas concentrated within the explosive limits and an ignition source offered. In the paper, the characteristics of indoor gas leakages are disscussed and the theoretical models of the release rate and diffusion of gas are presented firstly.

The purpose of this study is to develop a thermal design tool for architectural designer by combining a heat balance simulation for urban surfaces, including buildings, the ground and greenery, with a 3D-CAD. This tool is constructed by improving the previous simulation model, which uses the Geographic Information System for the input data. The simulation algorithm is improved so as to predict the surface temperature distribution of urban blocks while taking into account the actual design of the outdoor space using the 3D-CAD system.

The proposition of an assessment method of wind condition in urban structures is presented in the paper. In the second part of the paper two virtual residential districts with different urban organisation have been investigated. An assessment model used to examine wind conditions in selected urban organisation structures defines quantitative and qualitative features of the study area. Two elements of the urban environment, wind conditions and urban development, are evaluated.

By k− ε  turbulence model, the indoor air fluid flow and heat transfer conjugated programs in the YZ25K air-conditioned passenger car are solved with SIMPLE algorithm. The effect of solar radiation and body heat is taken into account and these auxiliary heat flows are the source terms of the energy equation.

In this paper, three-dimensional air flow distributions in a typical island platform under both natural and mechanical ventilation operation modes were simulated for the whole process of the train entering, staying in and departing from the platform. The mechanical ventilation modes include over-platform supply/under-platform exhaust (OSUE) and overplatform supply/over- platform exhaust (OSOE). Based on the data obtained from the simulations, the effects of natural and mechanical ventilation system on platform air distribution were analyzed.

Cyclone purifier has been conventionally used for separating particles from exhaustion. This paper, however, tried to develop a cyclone purifier for fresh air treatment in ventilation. Simulations were carried out based on continuity equation, momentum equation, RNG k-epsilon turbulent flow equation and Discrete Phase Model; the discrete griddings were both structural and non-structural; the software used was FLUENT. The separation efficiencies, pressure drops and the flow patterns of air in the cyclone purifier were simulated.

The air barrier technique is to apply the special airflow through window fan to improve the thermal environment near the windows in winter and summer, and especially in winter, to simplify the air conditioning system of perimeter zone of office building and avoid condensation on the surface of window. By using numerical simulation, the paper analyzed the thermal environment of the office building, both applied the air barrier technique or not. The paper also compared the two different methods in winter and summer respectably.

In the previous study, a numerical method which simulates combined heat and moisture transfer process in solid desiccant materials was investigated. The calculation results successfully reproduced the cyclic process of the moisture adsorption and desorption. The validity of the numerical simulation method for the desiccant wheel was examined by the comparison between the experiment and the numerical simulation of the desiccant dehumidifier.