Experimental evaluation of rational pre-launch acceleration parameters to provide liquid-propellant rocket sustainer engine launch in microgravity

Tis paper presents the results of experimental investigation of liquid propellant deposition processes in the tanks of liquid-propellant rocket propulsion systems (LPRPS) in a free (unperturbed) orbital (suborbital) flight under the influence of a small pre-launch g-force, created by auxiliary engines before starting the sustainer liquid-propellant rocket engine (LPRE). Based on the dimensional analysis, the structure of dimensionless groups was formed. The groups determine the relationship between the time required for deposition on the tank intake device and the overload value, the filling degree and the propellant physical properties. Experimental studies were carried out on the zero-gravity facility, implementing the reduced weightiness conditions through free fall of the equipment tested, and on the microgravity aircraft following a Kepler curve flight pattern. The results of the experiments revealed that deposition rate is practically unaffected by viscosity. However, the experiments also indicated that starting from Bond numbers of 40…50 (the Bond number was determined by the minimum radius of free gas inclusions deformed during separational ascent), the dimensionless separation time is not affected by the Bond number. It was established that with a significant duration of the pre-start g-force pulse, the motion of gas bubbles in the liquid under this influence acquires a quasi-stationary character.