1998 Fiscal Year Final Research Report Summary
Experimental Study on Variety Modes of Smoke Movement on Fire
Grant-in-Aid for Scientific Research (C)
|Kyoto Institute of Technology
NITTA Katsumichi Kyoto Institute of Technology, Faculty of Engineering & Design, Professor, 工芸学部, 教授 (70026342)
|Project Period (FY)
1997 – 1998
|Smoke Movement / Ventilation Network Model / Variety Modes / Chaos / Model Experiment / Visualization / Analytical Calculation
It's a subject of discussion that the smoke flows in rooms, corridors or vertical shafts generated by fire should not be contrary to our expectations from the safety viewpoint of the human evacuation. The assessment of the existence of variety modes for the directions of smoke flows must be required in its early stage of the disaster prevention planning.
In our research, the verifications of the variety modes latent in the building ventilation system or the smoke vent system were done by both the approach of the analytical and experimental studies.
In our analytical study, it is shown that the governing fundamental equations of the ventilation (or smoke vent) system are non-linear, and the variety modes are caused by the variable buoyancy terms for the case of the unknown variable Cs), namely known heat supply rate (s). The concrete examples of the ventilation variety are shown by the numerical calculation results for the two or three story building, From the investigation for the related physical parameters, we could indicate that the wind speed have the most impact on the variety modes. In connection with the prediction in the occurrence frequency of a specified ventilation mode, we showed for the first time that the 'CHAOS' is possessed in the building ventilation and the flow patterns result in another mode with slightly different initial conditions of numerical calculation.
In our experimental work, we get the verifications of the ventilation variety by means of the model tests on the scales of 41100 and 61100. Two modes of ventilation were confirmed for the models of symmetrical three story buildings, though the five modes were admitted in the numerical calculation for the same conditions with the models. By the visualization test with liquid paraffin mist, the cause of the difference in the variety occurrence between the analysis and experiment.
Research Products (2 results)