Recent Experimental Efforts on High-Pressure Supercritical Injection for Liquid Rockets and Their Implications

Figure 26

Consecutive frames from high-speed shadowgraph movies or a coaxial injector (LN₂/GN₂ into N₂-filled chamber) with the acoustic driver turned off (in rows 1, 3, and 5) and on (in rows 2, 4, and 6) at ~3 kHz. Time increases from left to right with an interval of 55.6 ms between frames. The first two rows are at a subcritical chamber pressure (~1.5 MPa), the third and fourth rows are at a near-critical chamber pressure (~3.5 MPa), and the fifth and sixth rows are at a supercritical chamber pressure (~4.9 MPa). The acoustic driver is turned off for the first, third, and fifth rows and on for the second, fourth, and sixth at ~3 kHz. The light gray lines in the first and second rows connect fluid structure as they evolve in time. Davis and Chehroudi [42].