Numerical simulation of compartment fires: investigation of opening flow characteristics

Πικιοκός, Δημήτρης; Pikiokos, Dimitris

dc.contributor.author	Πικιοκός, Δημήτρης	el
dc.contributor.author	Pikiokos, Dimitris	en
dc.date.accessioned	2016-07-19T09:19:50Z
dc.date.available	2016-07-19T09:19:50Z
dc.date.issued	2016-07-19
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/43165
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.5222
dc.description	Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Υπολογιστική Μηχανική”	el
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc/3.0/gr/	*
dc.subject	Numerical simulation	en
dc.subject	FDS	en
dc.subject	Opening flow	en
dc.title	Numerical simulation of compartment fires: investigation of opening flow characteristics	en
heal.type	masterThesis
heal.generalDescription	The thesis was written under the supervision of Maria Founti, Professor at the School of Mechanical Engineering of the National Technical University of Athens, Greece, and director of the Laboratory of Heterogeneous Mixtures and Combustion Systems.	en
heal.classification	Fire Protection - Numerical Simulation	en
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2016-02
heal.abstract	The release of heat due to compartment fire causes the surrounding gases to move as a result of expansion and buoyancy. Flow fields encountered in enclosure fires are highly three-dimensional and span a large spatial extent. CFD simulations using the FDS code are presented, aiming to determine the best modelling approach to achieve optimum agreement between numerical and experimental data and the most accurate simulation of the flow field. Two experimental configurations were simulated, ranging from a small scale to a large scale compartment. Details of the experiments can be found in the work of Suard et al. (2015) and Bryant (Bryant, 2009a, Bryant 2009b) for each configuration respectively. The simulations investigated the effects of grid cells’ sizes from 10mm to 50mm for the small scale compartment and from 30mm to 100mm for the large scale compartment. Investigation has been made in the effects of setting both adiabatic or conductive wall boundary conditions and different heat release rates for the fire, including the four values of 15.5kW, 21.7kW for the small scale and 160kW and 320kW for the large scale compartment. The adiabatic simulations proved to perform poorly in almost all aspects for the examined quantities, at any heat release rate examined. The comparisons between experimental measurements and numerical simulation results, focused mainly on the temperature and velocity profiles at the opening of the enclosures. The investigation showed clear superiority of the fine meshed models, for all the cases examined. A grid of 10mm for the small scale and 50mm for the large scale compartment were able to model the flow field parameters adequately. Algebraic relations of the mass outflow and inflow rates of the burning compartment, dependent on various quantities, underwent careful manipulation in order to appear simplified and grouped since many of them appeared multiple times in the literature from different sources. The correlations were separated in two categories, estimating the mass flow rate of either the inflow or the outflow. The best performance in terms of mean absolute error was 9%-11% overestimation of the inflow and 4%-6% overestimation of the outflow. The error values of the aforementioned comparisons were used to further compare the results with one another in order to determine which discharge coefficient is most suitable for the cases examined. The results were doubtful giving a small lead to the values proposed by Prahl and Emmons (1975), namely 0.68 for both the inflow and the outflow coefficients. The average relative error of the correlation provided by Rockett’s (1976) work was also examined giving an underestimation of the thermal discontinuity height by 13.5%. The results were acquired after careful comparison to 14 experimental results using a doorway as their only opening, provided by Steckler et al (1982).	en
heal.advisorName	Φούντη, Μαρία	el
heal.committeeMemberName	Φούντη, Μαρία	el
heal.committeeMemberName	Μπουντουβής, Ανδρέας	el
heal.committeeMemberName	Ριζιώτης, Βασίλειος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Χημικών Μηχανικών	el
heal.academicPublisherID	ntua
heal.numberOfPages	117 σ.	el
heal.fullTextAvailability	true