A vacuum pumping system and method for a ramjet vacuum chamber

Abstract

The invention belongs to the technical field of ramjet engine tests, and in particular relates to a vacuumizing system and a vacuumizing method for a vacuum cabin of a ramjet engine. The system comprises a vapor source, a vapor distributer, a first-stage ejection device, a second-stage ejection device, a muffling tower and a switch valve, wherein the first-stage ejection device and the second-stage ejection device are connected in series; a vapor inlet of the first-stage ejection device communicates with the vapor distributor through the switch valve; a vapor inlet of the second-stage ejection device communicates with the vapor distributor; a vapor outlet of the second-stage ejection device communicates with the external environment through the muffling tower; a vacuumizing inlet of the first-stage ejection device communicates with the vacuum cabin to be vacuumized; and the vapor distributor is connected with the vapor source. The system and the method, provided by the invention, have the advantages of large working range and high vacuumizing ability.

Description

technical field [0001] The invention belongs to the technical field of ramjet testing, and in particular relates to a vacuuming system and method for a ramjet vacuum chamber. Background technique [0002] When the ramjet engine is performing a high-altitude simulated test run, it is necessary to eject the exhaust gas generated by the engine in the vacuum cabin and the simulated high-temperature air from the incoming flow to the outside of the cabin to maintain a certain degree of vacuum in the cabin. If the required vacuum degree cannot be reached, the engine will hold pressure and the test will fail. [0003] At present, the vacuum system adopts a two-stage steam injection device connected in series for vacuuming, and the negative pressure generated by the injection nozzle of the first-stage ejection device injects the gas in the vacuum chamber into the first-stage pump, and the working The steam and ejection gas are sucked into the secondary pump by the negative pressure ...

AI Technical Summary

Problems solved by technology

But this type of ejection device is only suitable for the situation where the incoming flow of the vacuum chamber is small and the vacuum degree is high. When the incoming flow of the vacuum chamber is large and the vacuum degree is not high, the capability of the secondary ejection device is not enough to extract The mixed gas of jet steam and primary working steam is all injected into the atmosphere, causing the gas blockage of the secondary inlet

This blockage will produce a "gasp" phenomenon, resulting in unstable pressure in the vacuum chamber, or even instantaneous overpressure, which brings risks to the test

[0004] At present, the capacity of the vacuum pumping system is only the maximum flow rate of 30kg / s to maintain the cabin pressure of 10-35kPa (absolute pressure). The vacuum pumping system cannot meet the large flow conditions

Therefore, although the first and second ejection devices are connected in parallel, although the suction vacuum is high, the working range is small, which seriously limits the test capability of the ramjet.

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