IJV2

The 3DFLOW code has been developed based on:
· The standard three-dimensional K-epsilon two-equation turbulence model;
· A modification for buoyancy effects;
· Wall functions applied to deal with solid boundary conditions;
· An adaptation of the SIMPLE algorithm.
The representative indoor air flows in conditioned spaces, including downward mixing, partition and displacement ventilation cases, were simulated and analysed in detail using the 3DFLOW code. Good agreement was found between the numerical predictions and experimental data.

In the present study, a numerical simulation to simulate an experiment for evaluating the cross-ventilation performance at an inflow opening by using Large Eddy Simulation (LES), the standard k-e model, and Durbin's k-e model was performed. Results showed that too much turbulent kinetic energy was produced at the leeward opening frame in the standard k-e model. However , Durbin's k-e model improved this defect , and reproduced the wind tunnel results fairly well, as did the LES approach.

A Local Dynamic Similarity Model, applicable to dynamic similarity of cross-ventilation, has been applied to outflow openings. Cross-ventilation performance at the openings on the outflow side has been evaluated, and the structure of air flows around the outflow openings has been studied by LES and wind tunnel experiments. It was found that LES reproduces the wind tunnel experiment results fairly well, such as the extensive increase of discharge coefficient in a small region where dimensionless room pressure, PR*, is low.

In computer simulations of buildings and other structures, in relation to HVAC and fire, it is fairly common to need to represent boundaries which are made up of double semi-transparent membranes. An obvious example is a double-glazed window. When setting up a Computational Fluid Dynamics (CFD) model of the building, it is sometimes the case that detailed representation of this type of boundary is superfluous, and the CFD user wishes simply to replace the assembly by thermal and radiative boundary conditions.

To evaluate the property of cross ventilation quantitatively, it is important that the calculated air flow field is compared with measurement. In this paper, the air flow field in the wind tunnel of the Building Research Institute of Japan (BRI) was calculated by CFD analysis using the standard k- e model, and the adequacy of the calculation was examined by comparison with measured values.

The National Institute of Standards and Technology (NIST) is conducting a study on the indoor air quality (IAQ) impacts and engineering solutions related to the transport of pollutants from attached garages to residential living spaces. Natural or fan-induced pressure differences across air leakage paths in house-garage (HG) interfaces can result in the transport of the contaminants generated in garages into adjacent living spaces.

The mechanism of cross ventilation is dealt with in this paper. The results are obtained by a combination of wind tunnel studies and CFD predictions using a Reynolds stress model as the turbulence model. All buildings have been exposed to a uniform velocity field and therefore the reference flow rate for an opening is equal to the velocity multiplied by the opening area. The openings were located at or close to the position of the stagnation point on the corresponding sealed building.

The present paper aims at investigating the indoor air quality in fifteen school buildings located in the greater Athens area. Experimental investigations were performed in fifteen different school classrooms and the concentration levels of various pollutants such as CO2, CO, TVOC, HCHO, and radon, were measured. Moreover, the experimental investigation included measurements of several environmental parameters such as temperature, relative humidity and air velocity inside each classroom, while ventilation was examined by estimating the air changes using the tracer gas technique.

The efficiency of an exhaust system is especially important in a kitchen environment in which the exhaust is located at ceiling level. The capture efficiency of the total system must be guaranteed so that the spread of impurities throughout the kitchen is prevented. A capture efficiency model is derived and it is used to estimate the efficiency of a ventilated ceiling.