Numerical methods to prevent pressure oscillations in transcritical flows

The accurate and robust simulation of transcritical real-fluid effects is crucial for many engineering applications, such as fuel injection in internal combustion engines, rocket engines and gas turbines. For example, in diesel engines, the liquid fuel is injected into the ambient gas at a pressure that exceeds its critical value, and the fuel jet will be heated to a supercritical temperature before combustion takes place. This process is often referred to as transcritical injection. The largest thermodynamic gradient in the transcritical regime occurs as the fluid undergoes a liquid-like to a gas-like transition when crossing the pseudo-boiling line (Yang 2000, Oschwald et al. 2006, Banuti 2015). The complex processes during transcritical injection are still not well understood. Therefore, to provide insights into high-pressure combustion systems, accurate and robust numerical simulation tools are required for the characterization of supercritical and transcritical flows.