Experimental Investigation of Reactive Liquid Oxygen/CH4 Coaxial Sprays

摘要

LOX/CH4 has aroused increasing interests as a promising green propellant combination. Experimental investigation of cryogenic reactive coaxial sprays of LOX/CH4 has been conducted in DLR, Germany. The sprays and flames have been investigated by visualization methods like shadowgraphy and imaging of the flame emission. The experimental Weber number ranges from 7000 to 20 000 and momentum flux ratio at 0.47-7.9. The liquid oxygen intact core length is measured from the shadowgraph images with 4000 frames per second acquisition rate and the power spectrum of the intact core length oscillation is analyzed. The results show that the dominant frequency of liquid jet oscillation is in low-frequency range and there are some high-frequency contents for jets at low J-number. J-number shows prominent effect on the dominant frequency of jet oscillation and increase of J-number or velocity ratio may result in decrease of the dominant frequency. Weber number does not affect the intact core oscillation obviously. Under the conditions investigated, the frequency of liquid core oscillation appears independent of the feed system and combustion process.