Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2001. / Includes bibliographical references.

Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2002. / Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 79-81). Also available via the Internet.

Thesis (M.S.) -- Worcester Polytechnic Institute. / Keywords: Hot surface ignition temperature; self-heating; combustible liquid additives. Includes bibliographical references (leaves 134-135).

Thesis (M.S.)--University of Central Florida, 2008. / Adviser: Michael Sigman. Includes bibliographical references (p. 118-122).

Digitized by Kansas State University Libraries

A study was made of the feasibility of putting hazardous area classification (HAC) on a more quantitative basis. A review of current HAC practice showed that the widespread policy of setting fixed zone distances around sources of hazard was subjective and sometimes led to inconsistencies between different codes of practice when applied to the same situation. Fatality and injury statistics were used to show that there is a significant risk to workers from the ignition of flammable atmospheres. which should be reduced. Data were researched and compiled to fit into a proposed framework for the quantification of HAC. These included information concerning leak source inventory: source leak frequency: and source leak size distribution. Mathematical models were collected which could be used to describe the emission and dispersion of flammable releases. Example calculations were performed for typical leak scenarios to illustrate the variation in hazard distances. Estimates were made of the ignition and explosion probabilities of flammable leaks. which depended princi pally on emission size. To compensate for uncertainties in the researched data. a fire and explosion model was devised to estimate the ignition frequency on a typical process plant. The model was applied to a "standard" plant which was formulated from researched data. By iteratively checking the estimated ignition frequencies against historical data it was concluded that reasonable agreement was achieved with some adjustment of the input data. The special problems of HAC of indoor plants were also addressed. It was concluded that the results of this study provided a basic framework for the quantification of HAC. although the quality of currently available data necessary for quantification is generally poor. The acquisition of better quality leak and ignition data should provide a platform from which the current work may progress. Further work should include the further refinement of the basic fire and explosion model to account for ignitions which HAC cannot protect against such as autoignitions. It was also noted that the behaviour of indoor releases requires clarification. together with the concept of a minimum flammable inventory below which there is negligible risk of ignition.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on February 12, 2010). Thesis advisor: Dr. Galen J. Suppes. Includes bibliographical references.

<p>A hot surface is one of the ignition sources which may lead to fires in the presence of aviation fluid leakage. Bleeding ducts and exhaust pipes that are at elevated temperatures are potential sources of ignition. A database of Minimum Hot Surface Ignition Temperatures (MHSIT) resulting from experiments conducted three decades ago at the Air Force Research Laboratory (AFRL), Dayton, OH has served as a valuable source of estimating safe operating temperatures. However, MHSIT for some of the aviation fluids such as Jet-A and MIL-PRF-23699 (lubrication oil) are not readily available. Further, the ranges of the hot surface and flammable liquids’ temperatures and the range of the air stream velocities need to be extended for use in higher pressure ratio and higher performance aircraft engines developed since the generation and interpretation of the original data. The air velocities (V_A) in the modern engines have increased by a factor of two and documenting their effects on the MHSIT for a range of test fluid temperatures and air temperatures (T_F, T_A) is important.</p> <p>The objectives of this study are to develop a generic test apparatus to study MHSIT and to model an air-fuel mixture space to find the range of temperatures and velocities that lead to ignition. Among various leakage scenarios, the test apparatus simulates spray (atomized particles injected through a nozzle) and stream (dripping from a 3 mm tube) injection. A semiempirical ignition model was developed using an ignition temperature and delay time expression based on an energy balance between the heat lost to the cross-stream flow, the heat added from the hot surface and the heat released by the nascent chemical reactions to estimate the MHSIT.</p> <p> </p> <p>MHSIT is measured including the effects of V_A, T_F, T_Aand the effects of obstacles. Ignition probability is evaluated as a function of the hot surface temperature. The probabilistic nature of the hot surface ignition process was established. New flammable fluids (Jet-A & MIL-PRF-23699) have been tested and MHSIT database was expanded. A large number of ignition experiments were completed to evaluate ignition probability at various flow conditions of aviation fluids: (1) Jet-A, (2) Hydraulic oil (MIL-PRF-5606) and (3) Lubrication oil (MIL-PRF-23699). Uncertainty of the experimental measurements for these tests have been documented. Air velocities were extended up to 7 m/s. Effects of flammable liquid and air temperature on MHSIT were studied. The empirical constants for the semi-empirical model were determined using these experimental data.</p><p>The ignition probability is strongly correlated with hot surface temperature and progressively weakly correlated with air velocity, fluid parcel size, air temperature, and test fluid temperature. Parameters investigated in this study are useful design choices considering MHSIT for a given flow condition.</p><p></p>