The absence of a dense potential core in transcritical injection

Abstract

Injection of cryogenic nitrogen into a chamber at supercritical conditions has become a popular test case for real gas CFD validation. However, there is a systematic discrepancy: a measured immediate drop of density upon entering the chamber could not be found with theory or CFD. It is shown here that heat transfer to the cryogenic injectant does take place and may explain the exhibited behavior. In a numerical study, different break-up modes could be reproduced by varying heat transfer inside the injector. This thermal break-up is essentially a new break-up mechanism, strongly associated with pseudoboiling, a supercritical state transition from liquidlike to gaslike.