Near-wall liquid film interaction with co-current gas flow inside nozzle and under outflow into vacuum

Visualization of Coolant Liquid Film Dynamics in Hypergolic Bipropellant Thruster

“…Then, V local gradually decelerates to being 0 m∕s at the film front. Since the trend of V local is consistent with V front , the effect of wettability on the film motion is insignificant, as previously reported by Yarygin et al [24].…”

“…One of the issues that arises is a lack of experimental data for coolant liquid film dynamics under an operating combustion condition inside a practical thruster. Yarygin et al [24] experimentally measured the film thickness and velocity subjected to a sonic air flow by using capacitance sensors and quantified the amount of droplet entrainment. Knuth [25] conducted experiments using the hot air flow with water as the liquid coolant in a tube.…”

Evaporation of Three-Dimensional Wavy Liquid Film Entrained by Turbulent Gas Flow

“…Table 1 shows the two types of analysis conditions, corresponding with the recent experiments for pipe flow [14] and flow on flat plate [5]. The distinct working liquid is ethanol and water, subjected to the fast air stream.…”

“…4 Entrainment ratio. The gas velocity is fixed as = 320m/s, while the gas density is varied in a vacuum chamber [14]. The liquid conditions are constant.…”

“…of a thin liquid film extending on a wall exposed to a fast gas flow is a general thermo-fluid issue in many practical situations, such as film-cooling technology [1][2][3], icing on aircraft wings [4][5][6], and drying of paints and cleaning solutions [7]. Past and recent studies including quantitative measurements [5,[8][9][10][11][12][13][14][15] provide a scenario that the turbulent gas flows over the initially smooth film, soon drives the film with complex wavy structures by Kelvin-Helmholtz (KH) instability as a roll wave, accelerates the wave crests producing transverse wave by Rayleigh-Taylor (RT) instability as a ripple wave, stretches ligaments, and eventually entrains droplets disintegrated by Plateau-Rayleigh instability, all in a sequential fashion. The waves intricately merge and break downstream [10,16] being a disturbance wave [5,13,17,18] with large amplitude.…”