الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
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Abstract
In this thesis, general CFD code (CFX‐16.2, ANSYS, Inc.) and Froude scaling modeling were validated with experimental data for developing atrium fires. Historically, CFX was validated with experimental data for compartment fires including natural ventilation only. In the present study validation was performed for developing fires during transient period in a large space, including a combination of natural and forced ventilation.
The present study investigates the measured data attained in Murcia Atrium fire tests using CFX. The tests were executed by burning heptane as a fuel for three different fires capacities (1.32, 2.28 and 2.34MW). Two different combustion models were used to present the combustion of heptane.
Four different approaches were employed to determine the predicted dynamic behavior of the smoke layer height and to evaluate the accuracy of CFX predictions.
The capability of Froude scaling modeling to replicate the fire dynamics in full-scale Murcia Atrium Fires tests equipped with natural and transient forced ventilation was investigated experimentally and numerically by using a 2:27 physical Scale Down Model (SDM) of the full-scale Atrium and CFX-Ansys16.2, respectively. Five experiments were conducted using different heptane fire capacities located at the center of the floor. Two different turbulence models were used for simulation namely the Shear Stress Transport (SST) and k-ε models. Experimental results of the SDM and full-scale atrium fire tests were compared with those predicted for SDM through the preservation of the Froude number to cover the gap between experimental facts and scientific understanding. The validations were focused primarily on the transient temperatures at near and far fire fields and the descending smoke layer. The predicted velocity and visibility were assessed. The results showed that Froude scaling modelling is acceptable from a threshold of greater than 50% of the full-scale.
The results display CFX predictions have a reasonable concord with the experimental data. Therefore, CFX can be a valid tool for performance‐based engineering to evaluate the smoke systems required for complex enclosed structures.
In addition, sensitively analysis for significant parameters were studied in this thesis to assess the performance of impulse ventilation system (IVS) to guarantee a safe evacuation of occupants, public and fire fighters due to fire in an existing underground car park. The significant parameters include parked cars, extract rate, jet fan number and fire location.
An analysis is performed using CFX to simulate 9 different scenarios in a 10,021 𝑚2 car park with a fire source of an experimental transient heat release rate to simulate two car fires. Results showed that the existing ventilation system is under expectation of tenability criteria for temperature and visibility. The influence of significant parameters on the IVS performance for smoke clearance was illustrated to provide a certain insight to performance-based design of IVS in an underground car park.