Excitation of slosh waves associated with low frequency impulsive reverse gravity acceleration of geyser initiation

Hung, R. J.; Shyu, K. L.

doi:10.1016/0094-5765(92)90071-p

Cited by 34 publications

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“…Since V f can be predetermined from geyser-initiation gravity level and average liquid height, as shown in Eq. (1), one can make a prediction of maximum flow velocity during the liquid reorientation for the various liquid fill levels.Comparisons of impulsive acceleration with a frequency of 1.0 Hz and with frequencies of O.l 20 -24 and 10 Hz 18 Selected sequences of time evolution of fluid reorientation with liquid-filled level of 70% for impulsive acceleration with frequency of 1.0 Hz: a) initial profile; b) flow profile before the initiation of geyser; c) flow profile with geyser; and d) flow profile after the ending of geyser.that use of the former frequency can activate higher maximumf low velocity (VJV f = 6.6-6.7) than that of the latter two cases of frequency-dependent thrust acceleration (V m /V f = 5.0-5.2 for/ -0.1 Hz 20 '24 ; and VJV f = 5.shows the ratio of time for liquid to reach the tank bottom to the average free-fall time t R /i f , and the associated parameters of t R and t f , in terms of liquid-fill levels, for impulsive acceleration with frequency of 1.0 Hz. The figure shows that the ratio of t R li f varies in the range of 1.1-1.2 for all liquid-fill levels, whereas t R and t f vary from 0.19 to 0.35 s (decreasing with increasing liquid-fill levels) and from 0.15 to 0.32 s (also decreasing with increasing liquid-fill levels), respectively.…”

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Medium-frequency impulsive-thrust-activated liquid hydrogen reorientation with Geyser

Hung

Shyu

1992

Journal of Propulsion and Power

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The requirement to settle or to position liquid fluid over the outlet end of a spacecraft propellant tank prior to main-engine restart, poses a microgravity fluid-behavior problem. Resettlement, or reorientation of liquid propellant, can be accomplished by providing optimal acceleration to the spacecraft so that the propellant is reoriented over the tank outlet without any vapor entrainment (or by eliminating vapor entrainment), any excessive geysering, or any other undesirable fluid motion to accomplish fluid management in a microgravity environment. The purpose of the present study is to investigate the most efficient technique to accomplish propellant resettling through the minimization of propellant usage through impulsive thrust. A comparison between the use of constant-thrust and impulsive-thrust accelerations for the activation of propellant resettlement shows that impulsive thrust is superior to constant thrust for liquid reorientation in a reduced-gravity environment. This study shows that when impulsive thrust with 0.1-, 1.0-, and 10-Hz frequencies for liquid-fill levels in the range between 30-80% is considered, the selection of 1.0-Hz-frequency impulsive thrust over the other frequency ranges of impulsive thrust is the optimum. Characteristics of the slosh waves excited during the course of 1.0-Hz-frequency impulsive-thrust liquid reorientation were also analyzed. 1 Nomenclature a g = geyser-initiation acceleration, cm/s 2 a m = scale flow acceleration associated with maximum velocity, cm/s 2 , defined by Eq. (5) D = diameter of propellant tank, cm / = frequency of impulsive thrust, Hz gt = impulsive reverse-gravity acceleration, defined by Eq. (6) &0 = geyser-initiation gravity level, g 0 go = normal Earth gravitational acceleration = 9.81 m/s 2 h -average liquid height, cm h m = maximum liquid height, cm L = height of propellant tank, cm L m = scale length of maximum liquid height, cm, defined by Eq. (4) i f = average free-fall time, s t m = time for observing maximum flow velocity, s t R = liquid reaching tank bottom time, s V f = average free-fall velocity, cm/s, defined by Eq. (2) V fm = free-fall velocity from maximum liquid height, cm/s, defined by Eq.(3) V m = maximum flow velocity, cm/s

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