A 1D model for the unsteady gas dynamics of ejectors

Ejectors are passive mixing devices that might operate in time-varying conditions, e.g., at start-up or during transients. Nevertheless, modeling efforts literature have mostly been focused on steady conditions. In this work, we propose a novel 1D unsteady model for supersonic single-phase ejectors based pipeline analogy with two inlets and one outlet. Conservation of mass, momentum energy is internally enforced each domain through gas dynamic equations, across the domains by junction model. The characteristics-based formulation admits solution critical sub-critical regime, including backflow, as long primary nozzle choked. Furthermore, not restricted to sonic ejectors. To authors’ knowledge, first enable ejector simulations boundary conditions operating regimes. was calibrated validated experimental data state benchmarked against 2D URANS simulation featuring sudden increase back pressure, triggering traveling pressure waves burst backflow. results show can correctly predict performance stream-wise evolution relevant integral quantities both transient