Assessment of Cavitation Models for Computational Fluid Dynamics Analysis of Erosion Risk in a Hydrocarbon-Fueled Nozzle
Technical Report,01 Jan 2017,31 Aug 2018
US Army Research Laboratory Aberdeen Proving Ground United States
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Shear-driven cavitation plays an important role in many technological applications, particularly in fuel injectors for piston and gas-turbine engines. Cavitation affects the performance and longevity of fuel injectors hence it is desirable to understand and predict its behavior since it can have favorable as well as adverse effects. Although there have been a vast number of studies, a full understanding describing its behavior has not yet been achieved. This is in part due to the complexities associated with cavitating flows, including internal flow physics, two-phase flow, and non-equilibrium thermodynamics. In this work, an assessment of the AVL-Fire computational fluid dynamics CFD solver coupled to an Eulerian-Eulerian cavitation model is conducted to investigate cavitation onset and the risk of erosion damage in a nozzle. The cavitation models in AVL-Fire are interrogated by comparing its ability to capture cavitation onset to experiments from a laboratory-scale optical nozzle. The models are also compared to existing CFD models across nozzle conditions in the range 20 dP 85 bar using n-dodecane fuel. The models captured the cavitation process near the injector wall regions and were able to predict the critical cavitation points and the chocked flow regions, as well as quantify erosion damage. The findings will be useful to guide the design of innovative Army propulsion technologies with improved engine endurance and enhanced performance.
- Fluid Mechanics
- Reciprocating and Rotating Engines