Self-pulsations in coaxial injectors with central swirl liquid stage

Effects of Recess on the Self-Pulsation Characteristics of Liquid-Centered Swirl Coaxial Injectors

“…Among these geometrical parameters, recess length acts as a key parameter in determining self-pulsation characteristics. Im et al [6,11] figured out that the self-pulsation zone becomes wider when increasing the recess length, whereas self-pulsation frequency has no clear trends. However, Bazarov et al [4,7] found that there exists an optimum recess length, making the self-pulsation zone the widest.…”

“…The frequency of self-pulsation is linearly proportional to the liquid and gas axial Reynolds number [5] and is more dependent on the liquid Reynolds number [6]. The ambient pressure suppresses self-pulsation and decreases self-pulsation domain [4,6]. Among these geometrical parameters, recess length acts as a key parameter in determining self-pulsation characteristics.…”

“…The self-pulsation characteristics of the LCSC injector are greatly influenced by injection conditions and injector geometrical parameters. The frequency of self-pulsation is linearly proportional to the liquid and gas axial Reynolds number [5] and is more dependent on the liquid Reynolds number [6]. The ambient pressure suppresses self-pulsation and decreases self-pulsation domain [4,6].…”

“…In another paper [9], they suggested that Kelvin-Helmholtz-like instabilities on conical liquid sheet surfaces are likely to excite self-pulsation. Im et al [5,6] studied the self-pulsation of LCSC injectors systematically and concluded that self-pulsation occurs due to the dominant wave of the liquid sheet. Huang et al [10] pointed out that self-pulsation is a result of resonance because is no extra vibration driver, and it is impossible to resonate between vapor and liquid states.…”

“…As self-pulsation can cause pressure and flow rate oscillations, and finally those oscillations can amplify the combustion instability in rocket engines, self-pulsation must be suppressed [5,6]. To control self-pulsation, a thorough mechanism of selfpulsation is needed.…”