Date of Graduation

2016

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

V'yacheslav Akkerman

Committee Co-Chair

Jerome Taveau

Committee Member

Arvind Thiruvengatam

Abstract

Accidental expositions in enclosures, such as industrial and residential buildings, lead to a pressure rise that may injure or kill the personnel as well as damage the construction. For example, an overpressure as small as ∼0.1 atm is enough to kill a person or break glass items, while ∼1 atm overpressures may crucially destroy the structure, including collapsing the walls. A standard remedy strategy against such a disaster is employing venting areas such as windows to allow the expanding gas to escape and thereby reducing the maximal overpressure. There are two common ways how to predict the pressure rise in an enclosure for a given vent size; location and geometry. Namely, either phenomenological models, identified from particular experiments, or those from the comprehensive computational fluid dynamics (CFD) are usually used. However, there is a certain gap between these two approaches. Phenomenological models are simple but less accurate and while CFD models, despite being more accurate, are often too computationally expensive and complex to employ, promptly, in any situation. There is therefore a critical need to reduce such a gap by establishing a simple but viable computational model that will imitate the experiments from the practical reality with an acceptable level of accuracy.;This thesis is a step in developing such a computational explosive vent analyzer (EVA). Specifically, the EVA calculates the initial overpressure in an enclosure for a given vent size, equivalence ratio, enclosure geometry and breaking pressure of the vent cover if necessary. The computational platform is designed to be computationally inexpensive and simple in that it is easy to learn, employ and modify for different situations. The results obtained are generated for near-stoichiometric, methane-air explosions for the venting area of 2.7 m2 and 5.4 m2, with a central or rear ignition. These results are validated by the experimental and computational data from the literature, with good qualitative and quantitative agreement shown. It is demonstrated that the EVA can predict the timing and magnitude of the overpressure in the experiments with accuracy comparable to the best CFD models in the field. Parametric studies are discussed for various vent areas and equivalence ratios.

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