Experimental studies of hydrogen-air mixing processes.

摘要

Increasing concerns over pollutant emissions and fuel scarcity have led to increased interest into new fuel sources in general and hydrogen in particular. Hydrogen has the potential to be sourced as a renewable fuel with no net carbon emissions and low pollutant emissions. However, to achieve the low pollutant emissions, a thorough understanding of the fuel and its mixing properties are required. To aid in this understanding, this study focuses on the mixing processes of hydrogen and air. To accomplish this understanding, measurements of fuel concentration and velocity were obtained at a number of planes downstream of the fuel injection plane. Injection type and flow conditions were varied to evaluate their impact on the mixing, and measurements were obtained for both hydrogen and methane. The primary findings of the study suggest that for low pressure drop fuel injection the jet-momentum flux ratio is the controlling value for the injection mixing behavior, and that little to no discernable difference was found in the spatial distribution of hydrogen in comparison to methane. Additionally, it was found that the addition of flow swirl improved mixing near the injection plane, but that it created a reduced level of radial mixing further downstream as it worked to maintain a core of high fuel concentration. Overall, the results suggest that many of the standard design tools employed for more standard fuels such as methane still hold true for hydrogen, with the difference between the two being the larger volume of hydrogen due to its lower density.