Application of CFD for interior flow analysis influenced by exterior conditions


Krajewski G., Żurański J. A., Węgrzyński W., Sulik P.

Building Research Institute, Warsaw, Poland
Fire Research Department and Building Structures and Geotechnics Department

The aim of the paper is the presentation of application CFD analisys for interior flows in chimneys and flats in a building. It is a summary of a case study of fatal intoxication by carbon monoxide coming from a gas heater of flowing water at a bathroom. That kind of accidents mostly happens due to problems with ventilation and very popular old construction gas water heaters. Closed, airtight windows are the main causes of the production of carbon monoxide but sometimes wrong construction of the chimney outlets versus the roof shape causes the backdraught of combustion products. The paper deals with an accident which took place in one of Polish cities. Gas heater of flowing water installed in a bathroom at the first floor was connected to the vent pipe with a low outlet. During windy weather conditions, at the end of October, so in a cold season, one of the inhabitants of the apartment died in bathroom due to carbon monoxide intoxication.
An investigation has been carried out, which has shown various irregularities in the construction of the chimney, as well as misuse of the outlet. Explanation of the causes of the accident was possible thanks to the numerical calculations using CFD methods, the scope and extent of which is presented in the paper. Different shapes of chimney outlet were taken into consideration during the analysis. Three dimensional model of a building and flats was created. That kind of simulations gives the possibility to find out the reason of the accident.

1. ANSYS Fluent 6.3.26 User’s Guide.
2. Krajewski, G., Zuranski, J.A. 2009. Effect of wind on evacuation of burned gas from home gas appliances – a case study. – XII Polish Conference of Science and Technology Building Physics in Theory and Practice. Lodz – Slok (in Polish).
3. PN-77/B-02011 Loads in static calculation. Wind loads (in Polish.).
4. PN-89/B-10425 Flues and ventilating ducts of bricks. Technical requirements and acceptance tests (in Polish).