The use of hypochlorite for water disinfection is source of chloramines production, which are transferred to the atmosphere.Nitrogen trichloride (NCl3) is the main component, which is a major cause of respiratory and ocular problems for swimmers and lifeguards. This first part comprised a sampling campaign concerning the measurement of NCl3 in a swimming pool (Picardie-France) during 15 days (October 2001). This campaign concerned the air quality diagnostics and showed that the majority of detected levels were critical (P50 = 0,44 mg/m 3 ).
Basis of this work was the question of the formation of air flows in ventilated test rooms with regard to wall influences. In order to determine the effects of the room geometry and the air inlet angle a on the airflow a jet which was placed just below the ceiling was observed in symmetrically designed test rooms. Since there is a correspondence between measurement and CFD simulation, velocity vectors are extrapolated from the CFD simulation and analysed for different geometrical data.
A validated CFD model was used to generate concentration distribution data for CO2, radon and moisture in a Hong Kong workshop with displacement ventilation.Contaminant concentration distribution depends on the contaminant source type and location. A low concentration may be obtained in the occupied zone when the contaminant source is associated to a heat source whose thermal plume is sufficiently strong to reach the upper zone.
The objective of this paper was to illustrate the potential of the CFD technique to compare the effectiveness of different general ventilation systems in reducing the workers' exposure to styrene vapour in a workroom. . Thanks to the CFD technique predicted airflow velocities and styrene distribution are shown for the 3 different ventilation arrangements at identical planes across the room. And predicted values of styrene concentration at workers'position are given.
2 examples of extract systems are presented in this paper : the first one concerns dust removal in a public waste plant and the second smoke separation in a smoker/non-smoker zone with no visual impact (i.e. no walls).Thanks to the CFD simulation, proper exhaust systems for dust and smoke have been successfully designed and optimised for each case with simulation results. The proposed solutions were then realized and with few minor modifications led to excellent working conditions on the one hand and excellent smoke caption on the other hand.
This paper deals with a computer simulation of airflow and indoor environment in livestock buildings. Simulation results have been analysed and visualized with a Virtual reality visualization . The definition of virtual reality is given first , then the presentation of the 3 Virtual reality systems possibly used for the visualization, and finally a simulation tool.
5 cases were selected to demonstrate the different simulation and visualisation possibilities for people form the industry.
The REinforced EXhaust System (REEXS) is a local ventilation principle for industrial ventilation with improved efficiency for capturing contaminants released by working processes .This paper discusses the validation of a 3D CFD model for the determination of the capture efficiency of standard local exhaust ventilation systems.That study has shown good results in 3 ways :- Properly designed REEXS hoods , compared to conventional exhaust devices have a significant increase capture efficiency.- CFD is an excellent tool to predict different local ventilation strategies in a quantitative way.
The first part of this paper deals with the performance of a ventilated ceiling system. Field measurements were made in a kitchen of a dietitics school in Kyoto practising mass cooking. The kitchen was half equipped with air canopy hoods to compare with the ventilated ceiling system.
A numerical simulation was conducted with CFD in order to understand the trends of the indoor thermal environment of the kitchen.
Calculations using CFD are presented for adventitious openings in which the flow is not fully developed. It is shown that the quadratic equation performs significantly better than the power law i.e. a recent claim that the power law equation is preferable to the quadratic equation under such circumstances is not supported. Other recent claims that have been made to support the power law in preference to the quadratic are also examined and reasons are given as to why they are unfounded for conditions of typical, naturally driven air infiltration.
This paper deals with two general approaches used to determine multizone air flow by tracer gas experiments : a tracer gas decay model and a simultaneous release of n different tracer gases in n zones (n x n approach) . The results show a suitable agreement between the model and measurements made, at work-time, in a 3-store building equipped with an hybrid ventilation system.