Aviation Fuel Cavitation in a CD Nozzle: A Quantitative Experimental Characterization

This work describes experiments aimed at clarifying several physical aspects of aviation fuel cavitation. The experiments are performed in a simple two-dimensional converging-diverging (CD) nozzle geometry with JP-8 fuel replaced by dodecane, a single component surrogate and its primary component by weight. Experiments are focused on gaseous cavitation with air micro-bubbles injected at the nozzle inlet. Carefully controlled initial void fraction leads to bubble growth in the bulk of the fluid and quasi-1D flow patterns downstream. These experiments seek to characterize the flow patterns with particular focus on propagating shock waves that form due to collapse of gaseous bubble clouds. Experimental documentation is made through arrays of static and unsteady pressure sensors, high-speed video and a volumetric flow rate meter. The results are analyzed to obtain choked mass flow rate, distributions of mean streamwise pressure, shock propagation speed, local shock passage frequency, and static pressure jump across the bubbly shock.