Combustion Characteristics and Energy Utilization of Hydrogen-Blended Fuels

Due to the stress from the shortage of hydrocarbon fuels and the reduction of greenhouse gases, this research project is aimed at energy conversion and utilization of hydrogen blended fuels such as hydrogen-natural gas (methane), hydrogen-primary reference fuels (octane), and synthesis gases (syngas or reformer gases). The combustion characteristics of the hydrogen blends are investigated, and effects of hydrogen addition in engine designs and performance are studied. The following contents of the three-year project provide the fundamental knowledge to hydrogen energy application and solution to hydrogen safety issues. 1. The analysis of laminar flame speed of hydrogen blended fuels: The basic chemical and physical properties, thermodynamic and transport properties, chemical equilibrium and kinetics of hydrogen blends are analyzed theoretically. The laminar flame speeds of the blended fuels are computed and compared with a model of free-propagation premixed flames. The effects of the equivalence ratio and the amount of hydrogen are discussed at various atmospheric pressure and temperature. The equivalence ratios cover the range from lean-burn to rich-burn, and the amount of hydrogen is varied from none to 100%. 2. The analysis of flammability of hydrogen blended fuels: By using the configurations of counterflow premixed flames and counterflow diffusion flames, the flammability of hydrogen blends are investigated. The extinction boundary of premixed flame is constructed with the equivalence ratios and the stretch rates as coordinates, while the flammability limits of diffusion flames are computed with the stretch rates and the percentage of diluents (like nitrogen) or extinguish media (such as carbon dioxide and water) as variables. The model predictions of the flammability provide the combustion applications and fire safety for utilizations of hydrogen blends. 3. The combustor design and combustion analysis of hydrogen addition to microturbine: For the hydrogen combustion or hydrogen addition in microturbines, the combustor designs and combustion properties are studied with different hydrogen blends. The combustor performance including combustion efficiency, flammability, ignitability, pressure loss, flame stabilization, flashback, cooling, pattern factor and emission are examined with model analysis to evaluate the benefits of engine by adding hydrogen.

Project ID:PB9706-1243
External Project ID:NSC96-2221-E182-033-MY3