Vacuumizing system and method for multi-time low-vacuum-degree high-modulus test of liquid rocket engine

The invention provides the vacuumizing system and method for a multi-time low-vacuum-degree high modulus test of a liquid rocket engine in order to meet the vacuumizing requirement for multi-time vacuum state starting of the engine in the high modulus test of the liquid rocket engine. The system comprises a nitrogen ejector and a vacuum pumping unit, wherein an outlet end of the nitrogen ejector is connected with a nitrogen conveying pipeline, and a manual isolating valve is arranged on the nitrogen conveying pipeline; an outlet end of the vacuum air extractor is connected with a vacuumizing pipeline through a corrugated pipe; the nitrogen conveying pipeline and the vacuumizing pipeline are connected in parallel and then are connected to a vacuum cabin; high modulus test vacuumizing is carried out in a mode of combining a nitrogen ejector and a vacuum pump for the first time, and a problem of potential safety hazards caused by waste gas of propellants and combustion products to waste gas suction of vacuum equ