Analytical Study of the Cavitation on a Vibrating Wall

Cavitation induced cylinder liner erosion can be a significant durability problem in high power density diesel engines. It is typically discovered in the field, thus causing costly redesigns. The application of a predictive simulation to analyze the liner cavitation process upfront could identify the problem early on and enable significant savings. Hence, this work investigates the ability of the computational fluid dynamics (CFD) multiphase flow simulation tool to handle vibration induced cavitation. A flow of liquid through a U-shaped duct is analyzed, where a middle segment of the duct is set to vibrate in a manner resembling vibration of the cooling jacket walls in an internal combustion engine. Velocity, pressure and vapor concentration fields are tracked for two cases, distinguished by different frequencies of duct wall vibration. In a high-frequency case, a sharp increase in the volume fraction of the vapor phase is observed near the vibrating wall, with a higher peak value occurring at the upstream end of the section. The observed changes in volume fraction correspond to the displacement cycle of the mesh and do not change from cycle to cycle. Results illustrate the evolution of the cavitating flow along the axis of the duct, with cavitation being initiated and most pronounced at the transition from the upstream elbow to the straight vibrating section. Overall, the results demonstrate the ability of the multiphase flow CFD code to detect conditions leading to vibration induced cavitation and to characterize the spatial evolution of the vapor fraction.