Fläkt Woods, which manufactures a wide range of ventilation equipment, has undertaken a programme of experimental verification of the concepts of new displacement ventilation equipment, as well as validation of a CFD (Computational Fluid Dynamics) package

The accumulation of heat, contaminant and water vapour into the upper part of rooms is utilized in stratification and zoning room air conditioning strategies. For the zoning strategy the plume penetration through the supply air jet is an essential parameter in modelling the temperature, concentration and humidity in the lower and upper zones of the room. This paper presents an analytical method for modelling the plume penetration for an air distribution method based on horizontal inclined jets of industrial grilles.

The mean velocity in rooms predicted by CFD simulations based on RANS equations differs from the mean (in time) magnitude of the velocity, i.e. the mean speed, in rooms measured by low velocity thermal anemometers with omnidirectional sensor. This discrepancy results in incorrect thermal comfort assessment by the CFD predictions as well as incorrect validation of the predicted velocity field. In this paper the discrepancies are discussed and identified, and a method for estimating the mean speed based on the CFD predictions of mean velocity and kinetic turbulence energy is suggested.

The contribution deals with the research on temperature fields in rooms heated in differentways at heating-up as well as in steady state conditions. The investigations are being carried out byphysical modelling with the use of interferometry, numerical modelling as well as measuring real rooms by thermocouples. The results show that interferometric research of two-dimensional temperature fields can be used for modelling in smaller heated rooms, in cars and various air-conditioned boxes. Numerical modelling seems to be more effective and can be used in wider range of application.

A Lagrangian-Eulerian model for the dispersion of solid particles in a three-dimensional, incompressible, laminar or turbulent flow is reported, tested and partly validated. Prediction of the continuous phase is done by solving an Eulerian model using a Control-Volume Finite Element Method (CVFEM). A Lagrangian model is also applied, using alternatively an analytical and a Runge-Kutta 4th order method to obtain the particle trajectories. The effect of fluid turbulence upon particle dispersion is taken into consideration through a simple stochastic approach.

The paper describes the design of a fire and a smoke source for scale-model experiments with smoke ventilation. It is only possible to work with scale-model experiments when the Reynolds number is reduced compared to full scale, and it is demonstrated that special attention to the fire source (heat and smoke source) may improve the possibility of obtaining Reynolds number independent solutions with a fully developed flow. The paper shows scale-model experiments for the Ofenegg tunnel case.

The air movement in the occupied zone of a room ventilated by displacement ventilation exists as a stratified flow along the floor. This flow can be radial or plane according to the number of wall-mounted diffusers and the room geometry. This paper addresses the situations where plane flow is obtained and a semianalytic expression for the velocity level in the occupied zone is given.

This study examines the way of utilizing a ceiling fan for airflow control in a large air-conditionedroom. Although it seems that CFD simulation is useful in predicting the airflow around a ceiling fan, modeling of a ceiling fan as a body of rotation is very complicated. Therefore, in this study, airflow of a ceiling fan is modeled as boundary conditions of air velocity data measured near the ceiling fan.

The techniques available for the simulation of the complex geometries common in air diffusers are quite different from the ones optimized for a complete room simulation. For this reason the full room simulation usually neglects the complexities of the diffusers introducing ad hoc boundary conditions
often requiring extensive experimental setups for a correct definition. An alternative approach could be the use of numerical analysis for the diffuser characterization. In this work a detailed analysis

This paper presents an analytical model for predicting the air flow and velocity in an open vertical air channel due to natural convection. It can be used in the study of ventilated windows and double-faade systems, which are arousing interest as an energy-efficient means of providing fresh air, daylight and solar radiation to rooms. Unlike most previous work in this field, it proceeds from known surface temperatures instead of known surface heat flux.