Toward a validated model of a transcritical fluid jet in crossflow

Numerical modeling of transcritical fluid injection into a high-speed gaseous crossflow faces significant challenges due to the presence of multiple physically relevant processes that manifest on different scales. Beyond mechanical jet breakup, the system involves heat transfer, interfacial mixing, and phase transitions—phenomena that remain incompletely understood. This work describes our development of an experimental framework designed to generate quantitative data on jet behavior, which will inform the creation and validation of computationally efficient, physically accurate numerical models. While in reality transcritical injection is specifically important for engine design, where liquid fuel is often injected into gaseous flow carrying the oxidizer, our benchmark experiment uses injection of carbon dioxide into a flow of air or nitrogen. Our approach involves creating benchmarks of progressive complexity, beginning with non-transcritical jet-in-crossflow configurations to ensure accurate representation of each relevant physical mechanism. Attention is also paid to facilitating quantitative comparison between experiment and numerics. Fully three-dimensional numerical results are used to inform the design of the experiment and the parameter selection (pressures, temperatures, flow rates).