The combustion behavior of methane and ethane is important to the study of natural gas and other alternative fuels that are comprised primarily of these two basic hydrocarbons. Understanding the transition from methane-dominated ignition kinetics to ethane-dominated kinetics for increasing levels of ethane is also of fundamental interest toward the understanding of hydrocarbon chemical kinetics. Much research has been conducted on the two fuels individually, but experimental data of the combustion of blends of methane and ethane is limited to ratios that recreate typical natural gas compositions (up to ~20% ethane molar concentration). The goal of this study was to provide a comprehensive data set of ignition delay times of the combustion of blends of methane and ethane at near atmospheric pressure. A group of ten diluted CH4/C2H6/O2/Ar mixtures of varying concentrations, fuel blend ratios, and equivalence ratios (0.5 and 1.0) were studied over the temperature range 1223 to 2248 K and over the pressure range 0.65 to 1.42 atm using a new shock tube at the University of Central Florida Gas Dynamics Laboratory. Mixtures were diluted with either 75 or 98% argon by volume. The fuel blend ratio was varied between 100% CH4 and 100% C2H6. Reaction progress was monitored by observing chemiluminescence emission from CH* at 431 nm and the pressure. Experimental data were compared against three detailed chemical kinetics mechanisms. Model predictions of CH* emission profiles and derived ignition delay times were plotted against the experimental data. The models agree well with the experimental data for mixtures with low levels of ethane, up to 25% molar concentration, but show increasing error as the relative ethane fuel concentration increases. The predictions of the separate models also diverge from each other with increasing relative ethane fuel concentration. Therefore, the data set obtained from the present work provides valuable information for the future improvement of chemical kinetics models for ethane combustion.

Shock-tube experiments were performed with syngas mixtures near atmospheric pressure with varying equivalence ratios behind reflected shock waves. Pressure and hydroxyl radical (OH*) emission traces were recorded and used to calculate ignition delay time for a single mixture at equivalence ratios of [phi ]=0.4, 0.7, 1.0, and 2.0 over a range of temperatures from 913-1803 K. The syngas mixture was tested at full concentration as well as with 98% dilution in Argon. The full concentration mixtures were used to compare ignition delay time measurements with the theoretical calculations obtained through the use of chemical kinetics modeling using the Davis et al. mechanism. The dilute mixtures were used to study the OH* emission profiles compared to those of the kinetics model. The model was in poor agreement with the experimental data especially at lower temperatures with an ignition delay difference of more than an order of magnitude. These ignition delay time data supplement the few existing data and are in relative agreement. The species profile comparison of OH* compared to the model also showed poor agreement, with the worst agreement at the highest temperatures. While the disagreements with ignition delay time and profile comparisons cannot be explained at this time, the data presented support other findings. The data provide additional information towards understanding this disagreement relative to syngas mixtures despite the relatively well known kinetics of the primary constituents Hydrogen and Carbon Monoxide.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Approximately 14,500 people were killed in traffic crashes where the driver was legally intoxicated in 2005, constituting 33% of all traffic fatalities that year. While social efforts to reduce the number of traffic fatalities have shown to be moderately successful, alcohol has remained a factor in 40% of all traffic deaths over the past decade. Transdermal ethanol detection is a promising method that could prevent drunk driving if integrated into an ignition interlock system; potentially preventing 90 million drunk driving trips a year in the US. However, experimental data from previous research has shown significant time delays between alcohol ingestion and detection at the skin which makes real time estimation of blood alcohol concentration via skin measurement difficult. Using a validated model we studied the effects that body weight, metabolic rate and ethanol dose had on the time lag between the blood alcohol concentration and transdermal alcohol concentration. The dose of alcohol ingested was found to have the most significant effect on the skin alcohol lag time. Additionally, custom transdermal ethanol sensors were designed and fabricated and a pilot study on human subjects was conducted to determine if inexpensive transdermal ethanol sensors could be used to detect alcohol in drivers. / Master of Science

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Mehdi Namazian. / Ph.D.