Mixing Length of Hydrogen in an Air Intake

Greg Lilik Due: 5/1/07 EGEE 520 Abstract Hydrogen is currently being examined as a transportation fuel. One example of the way in which hydrogen has been examined is in diesel pilot ignited hydrogen combustion. This is achieved by injecting hydrogen into the air intake of an engine. The mixing of fuel and air greatly effect the polluting emission created during combustion. The hydrogen and air should be mixed homogenously to reduce polluting emission. A two-dimensional jet in a cross flow model was created to examine the mixing length of hydrogen being injected into the air intake of an engine. The model was created in Comsol Multiphysics 3.3 and was governed by the turbulent incompressible NavierStokes equation and the convection diffusion equation. Given the parameters used in the model, hydrogen and air move at a rate of 14.98 m/s homogenously mix in 0.052 s at a length of 0.77 m. The model was qualitatively compared to experimental results from a jet in a cross flow experiment and both appeared to agree with each other.