Due to the limitations of computer storage and time the flow boundary conditions at an air inlet device have to be specified for numerical simulations of air flow patterns in rooms. With regard to this the present work gives velocity measurements near an industrial air inlet using a Laser-Doppler-Anemometer. From the stochastic velocity data the time-averaged velocity components, standard deviation and turbulent kinetic energy are evaluated.

The paper discusses methods to set boundary conditions at the air supply opening in predictions of room air flows with computational fluid dynamics. The work is a part of the International Energy Agency project "Air Flow Patterns within Buildings", Annex 20. The air supply terminal in the Annex 20 project is a commercial diffuser which creates a stagnation region and a complicated wall jet below the ceiling. Fairly well predictions in the wall jet region were obtained replacing the diffuser by a simple opening which has the same momentum flow as in the diffuser.

Recent full scale experiments has detected the presence of low Reynolds number effects in the flow in a ventilated room. This means that one are unable to predict the flow patterns in some geometries for air change rates - or Reynolds numbers - which are relevant for ventilation engineering by a standard model of turbulence. In this paper it is investigated if it is possible to simulate and capture some of the low Reynolds number effects numerically using time averaged momentum equations and low Reynolds number k-e model.

Modern inlet devices applied in the field of ventilation of rooms are getting more complex in terms of geometry in order to fulfil the demand for thermal comfort of the occupants in the room and in order to decrease the energy consumption This expresses the need for more precise calculation of the flow jield. In order to apply CFD for this purpose it is essential to be able to model the inlet conditions precisely and effectively, in a way which is comprehensible to the manufacturer of inlet devices and in a way which can be coped by the computer resources.

Numerical modelling is performed to predict air movement, thermal comfort level and contamination distribution within an open office space. The office located in the building interior has a concentrated thermal load at its center and is conditioned by cool air delivered from a ceiling-mounted linear diffuser. the air velocity and temperature distributions and contaminant dispersion in the office are calculated for three different cooling loads and air exchange rates with a three-dimensional turbulent finite difference model.

Results of 3-D computational fluid dynamic simulations of the air flows, temperature distribution and contaminant remove efficiencies for typical workstation configurations which include the option for localized supply of outdoor air will be presented. A typical office configuration including desks, partitions, localized heat and contaminant sources will be modelled. The results will be compared to similar simulations the same workstation environment using ceiling supply and return plenum configurations.

The airflow pattern and thermal comfort in a naturally ventilated classroom were predicted using CFD techniques. The CFD model for turbulent flow consists of equations for the conservation of mass, momentum and thermal energy and the equations for the k-E turbulence model, taking account of the effects of buoyancy and obstacles in the room. The thermal comfort was assessed according to the predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD).

A mathematical model has been developed which will facilitate the prediction of infiltration rates within multi-zone buildings. The aim was to cater for: (i) significantly different temperatures in different parts of the building; (ii) flow paths at any height, including vertical connections between zones; and (iii) flow paths extending over large vertical distances. These aims led to the requirement in the associated computer program that the variation of pressure with height be accounted for independently within each zone of the building.

The concentrations of indoor pollutants should be maintained below recommended values at all occupied locations at any time. A design method based on minimal air change rates may not be satisfactory, since the ventilation effectiveness is determined not only by the nominal air exchange rate but also many other factors, such as the airflow pattern the space, location of contaminant sources, and properties of the contaminants. It is the objective of the present study to investigate numerically the effect of airflow patterns due to the various factors of ventilation effectiveness.

The evaluation of a code can be done by investigating two items: solving the correct equations and solving equations correctly and eficiently. An indoor airflow code VentAirI has been developed and is evaluated here. An evaluating procedure is suggested. The code is characterized by the standard high-Reynolds-number k-E model with wall function, the two-band radiation model and the SIMPLE algorithm. Test examples are: 1. A three-dimensional forced convection problem (Re=5000), 2. A natural convection problem (Ra=5 *10^10), 3.