Title

Dispersion of hydrogen in air in vented three-dimensional enclosures

Date of Award

1994

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

First Committee Member

Michael Swain, Committee Chair

Second Committee Member

T. Nejat Veziroglu, Committee Member

Third Committee Member

George Harvey, Committee Member

Abstract

The search for a viable alternative clean energy source is a subject of extensive contemporary research. Among the different sources identified to date, hydrogen seems to be the most promising. One of the important aspects that needs to be addressed before it is put into active use, is its safety. Hydrogen is the lightest gas, and explodes violently posing a potential explosion hazard when it may leak into the enclosed chamber of an automobile, or an aeroplane or in domestic settings. Such chambers can be made safe if vented properly.The experiments to test hydrogen leaks in a 3-D enclosure were conducted in the indoor setting of Miami laboratory of National Oceanic and Atmospheric Administration to find how hydrogen would behave under real world conditions. The laboratory had light, electric and other fixtures, and was representative of any industrial and domestic settings. The scaled experimental enclosure kept in the laboratory had an inlet at the center of the bottom and was vented by providing the outlet at the top. Two leakage rates of hydrogen of 977 ml/min and 1942 ml/min were tested to find any burnable mixture in the chamber.A theoretical analysis was done to determine hydrogen concentration levels for the experimental geometry. Flows arising out of mass transport in an enclosure can be predicted by solving mass, momentum and advection-diffusion equations. These transient strongly coupled (because of buoyancy term) nonlinear partial differential equations were solved by finite difference methods. FLUENT, a computational fluid dynamics software was used to solve these equations and determine the concentration levels of hydrogen in air.Theoretical study was also conducted to analyze unsafe scenarios that might occur in real life environs, such as kitchen enclosures, due to hydrogen leaks. Besides hydrogen, concentration levels of other commonly used gaseous fuels viz., methane and propane in air were determined and compared regarding their nature and extent of the burnable cloud produced.

Keywords

Engineering, General; Engineering, Automotive; Engineering, Mechanical

Link to Full Text

http://access.library.miami.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9426881