Mathematical modelling of factory fires

• Main Author: Chua, Wei Yang
• Other Authors: Ang Whye-Teong
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/167251
• Institution: Nanyang Technological University

Over the years, sawdust fires and explosions have always been a constant mainstay as a serious threat towards the wood and timber industry. Despite that, the prominence of their dangers always somehow seems to take a back seat as compared to their glaring exposure to fire risks. One of the main obstacles that risk managers have to face in these related industries, is the lack of understanding behind the self-igniting conditions of the sawdust pile, so they can take the appropriate measures to prevent the fire hazard. This project investigates the causes and determines the conditions required for the occurrence of spontaneous ignition in sawdust piling on top of a hot press. The report covers the derivation of equations that can be utilized in the determination of conditions that can result in unpremeditated ignition of the sawdust layer and the temperature distribution of the sawdust. This research focuses mainly on the graphical analysis of a one-dimensional heat flow sawdust model to ascertain a steady state solution, by using properties of sawdust layer height and its applicable maximum temperature. For an initial set of assumptions for certain constant assumptions, the sawdust pile model is evaluated over a series of different sawdust lengths from 0.3 m to 0.5 m in order to determine its critical length such that it is possible for ignition. The other parameters are then varied individually to study the effects of their variation on the steady state solution derived. Through this research, it has been uncovered that the variation in parameters, u_s, k, u_1, h and b is effective in altering the heat transfer process and the steady state temperature in the sawdust at certain threshold values. The results of this research show that the steady state solutions for a pair for defining equations can change depending on several factors, but the essence of the spontaneous ignition of sawdust holds true. Even in the presence of thermal equilibrium, once the maximum steady state temperature exceeds the critical ignition temperature of the specified sawdust material, then spontaneous ignition can occur.