Motivation and Background

The direct injection of hydrogen is a must for future internal combustion engines, however, such dedicated injectors are not yet (commercially) available. Fundamental research into the mixing behavior of such jets allows characterization of the turbulence intensity and velocity

in a two-dimensional plane. Such measurements were performed on axisymmetric jets of air in the past, but there is a lack of experimental data available for pulsed hydrogen jets inliterature.

Using a nanosecond-pulsed Yb:YAG fiber laser, high-speed imaging of round jets is possible (previous results, bottom-left), revealing the spatially- and time-resolved velocity of flow. When choked flow conditions are met, the compressible hydrogen jets are expected to exceed the speed of sound near the nozzle exit hole. Several injectors are available, with differing nozzle geometry. Additionally, a benchmarking strategy has already been established from which the loss of flow coefficients can be evaluated.

(Optionally) Mole fraction distributions and self-similarity results are available for certain injectors and could be compared with the obtained velocity results.

Tasks

• Modifications to existing setup
• Experimental plan
• Performing measurements
• Post-processing using Davis and Matlab/Python
• Result analysis
• Report writing