Mathematical Modelling and Simulation of Heat Dispersion Due to Fire and Explosion

Abstract

Kebakaran dan letupan adalah antara bahaya yang kerap berlaku dalam operasi loji kimia. Dalam kertas kerja ini, perbincangan ditumpukan terhadap model matematik serakan haba yang berpunca daripada kebakaran dan letupan. Model yang diselaku berasaskan MATLAB ini menggunakan kaedah perbezaan terhingga bagi menyelesaikan masalah yang berkaitan dengan fluks haba dan suhu. Tiga kelas kebakaran telah dipertimbangkan, iaitu kebakaran kolam, kebakaran kilat dan bebola api yang berkait dengan Cecair Didih mengembangkan Wap (BLEVE). Program penyelakuan ini digunakan untuk mengkaji kesan ketiga-tiga bahaya kebakaran tersebut yang diandaikan berlaku di kemudahan storan LPG, Loji Pandu Kejuruteraan Kimia, Universiti Teknologi Malaysia. Keputusan penyelakuan menunjukkan bahawa bebola api menyebabkan berlakunya mala petaka yang paling serius dengan kematian mencapai sehingga jarak 300 meter. Kata kunci: kebakaran; model pemindahan haba; penyelakuan; pengagihan fluks haba dan suhu. Fire and explosion are among the commonly occurring major hazards in the operation of chemical plants. In this paper, a mathematical model for heat dispersion in the event of an industrial fire and explosion is presented. The model is simulated numeracally within MATLAB environment to provide both the time and space dependence of the heat flux and temperature using a finite difference method. Three classes of fire were considered. These are pool fire, flash fire and fireball following the event of Boiling Liquid Expanding Vapour (BLEVE). The simulation program that has been developed is employed to study the impact of the three types of fire hazard on a LPG storage facility at the Chemical Engineering Pilot Plant in The Universiti Teknologi Malaysia. Thre results obtained highlights the various hazard condition for all the three events, with fireball imiposing the most severe condition by having safety distance of 300 meters away from the source of release, within which fatalities are expected. Key words: Fire; heat transfer model; simulation; temperature and heat flux distribution; finite difference