RU2773484C1 - Pulsed resonator ejector - Google Patents

Abstract

FIELD: jet technology.

SUBSTANCE: invention relates to jet technology, and specifically to gas ejectors and can be used in the industrial industry for pumping gases, dusty air mixtures in dustproof devices, in heating, ventilation and air conditioning systems, as well as in aviation in aircraft flow control systems at subsonic and transonic flight speeds. A pulsed resonator ejector, containing a mixing chamber connected to a rarefaction chamber, which is connected to the gas sampling area, and with a resonator installed in front of the mixing chamber, including a resonator cavity and a resonator tube, additionally contains a source of gas oscillations, including an elastic membrane installed with the ability to create vibrations gas in the resonator, and a device for generating membrane oscillations.

EFFECT: proposed device allows the ejection of gas from the external environment without the use of gas as a working fluid.

2 cl, 1 dwg

Description

The invention relates to jet technology, and specifically to gas ejectors and can be used in the industrial industry for pumping gases, dusty air mixtures in dustproof devices, in heating, ventilation and air conditioning systems, as well as in aviation in aircraft flow control systems (LA ) at subsonic and transonic flight speeds.

Devices (actuators) of various types are used to control the flow around an aircraft wing in order to rebuild it in a favorable direction. As a rule, these devices in one way or another form a gas jet, which can be directed to sensitive areas of the flow and cause its rearrangement in a favorable direction.

Known is an actuator operating on high pressure gas, which, using a special pneumatic device, forms a pulsating blow in one flow area and a constant suction of the boundary layer in another: Arwatz, G., Fono, I., and Seifert, A. "Suction and oscillatory blowing actuator modeling and validation," AIAA journal, Vol. 46, no. 5, 2008, pp.1107-1117. The main disadvantage of such actuators is the need to take high pressure gas from the engine or from a special compressor.

Also known is a pulsed plasma thermal actuator of the ejector type (RF patent No. 2637235), consisting of an underwater channel, a check valve, an ejector nozzle, a mixing chamber, a rarefaction cavity, an outlet diffuser and a discharge chamber with built-in needle electrodes, while the rarefaction cavity is made with a slot, connecting it to the surface of the wing.

The disadvantage of this actuator is the need for a high-power switching high-voltage power supply in the control system.

The closest analogue, taken as a prototype of the proposed device, is a pulsed resonator ejector (RF patent No. 2716650), containing a mixing chamber, a rarefaction cavity (rarefaction chamber) with a slot connecting it with the gas extraction area, and an outlet diffuser, and installed between the underwater channel and a mixing chamber, a cavity (resonator cavity) and a resonator tube forming together a resonator.

The disadvantage of this ejector is the need for a source of high-pressure gas.

The objective and technical result of the present invention is to reduce the consumption of high-pressure gas.

The solution of the problem and the technical result is achieved by the fact that the pulsed resonator ejector, containing a mixing chamber connected to a rarefaction chamber, which is connected to the gas extraction area, and with a resonator installed in front of the mixing chamber, including a resonator cavity and a resonator tube, additionally contains a source of gas oscillations, including an elastic membrane installed with the ability to create gas oscillations in the resonator, and a device for generating membrane oscillations.

The solution of the problem and the technical result is also achieved by the fact that the device for generating membrane oscillations is made in the form of an electric motor and a crank mechanism.

In FIG. 1 shows a diagram of a pulsed resonator ejector.

Pulsed resonator ejector (figure 1) consists of a source of gas oscillations, including a device for generating oscillations of the membrane 6 and an elastic membrane 1 installed with the ability to create gas oscillations in the resonator, including the resonator cavity 2 connected to the resonator tube 3, which goes into the mixing chamber 5, connected to a rarefaction chamber 4, which is connected by a channel to the gas sampling area for sampling the ejected gas.

The principle of operation of a pulsed resonator ejector is as follows: reciprocating movements of the elastic membrane 1, created by means of a device for generating vibrations of the membrane 6, form static pressure pulses of variable sign with a certain frequency and amplitude in the resonator cavity 2. At the positive half-cycle of pressure, a certain mass of gas is supplied to the resonator cavity 2 and further to the resonator tube 3, which, flowing out of the resonator tube 3, enters the mixing chamber 5, while ejecting gas from the rarefaction chamber 4. During this positive half-cycle, the entire structure operates like a classic ejector.

With a negative half-cycle of pressure, the gas begins to be sucked into the resonator tube 3 and further into the resonator cavity 2 from the mixing chamber 5 and the rarefaction chamber 4. In this case, the gas extraction from the rarefaction chamber 4 decreases, and from the mixing chamber 5 increases, which is undesirable in this case phenomena, since both of them reduce the total gas flow rate at the outlet of the mixing chamber and the time-averaged ejection coefficient. This happens at an arbitrary (non-resonant) frequency of membrane oscillations. The design works, but is not efficient.

When the frequency of supplying pressure pulses to the resonator cavity 2 coincides with the natural gas-dynamic frequency of the resonator, the intensity and constancy of the selection of the ejected gas from the rarefaction chamber 4 increases sharply. At the same time, on the negative half-cycle of the pressure pulse, gas extraction from the mixing chamber 5 practically stops and is carried out only from the rarefaction chamber 4.

Thus, gas suction through rarefaction chamber 4 occurs continuously both during positive and negative pressure pulses, and a practically stationary gas flow is established at the outlet of the mixing chamber. As a result, at the resonant frequency, the entire structure begins to work as a pulsed resonator ejector (RF patent No. 2637235), but does not require high-pressure gas flow.

To confirm the operability of a pulsed resonator ejector, several such devices were created and tested with different natural gas-dynamic frequency of the resonator, which was calculated using the Helmholtz formula (1) for the natural frequency of the resonator:

where c is the speed of sound, S is the cross-sectional area of the tube, l is the length of the tube, V is the internal volume of the cavity with the tube.

During the tests, to generate pulses of static pressure of variable sign, a round flat membrane made of rubber 1 mm thick was used, placed in a resonator. The membrane was set in motion by an electric motor through a crank mechanism with frequencies from 1 to 70 Hz. The dimensions of the mixing chamber were calculated using the EjCalc program developed by the authors (certificate No. 2019615248). The selection of the ejected gas was carried out from the external environment.

When using a pulsed resonator ejector as a flow control device, it is assumed that the ejected gas will be taken through a channel in the rarefaction chamber from the boundary layer of the streamlined surface.

Claims (2)

1. A pulsed resonator ejector containing a mixing chamber connected to a rarefaction chamber, which is connected to the gas sampling area, and with a resonator installed in front of the mixing chamber, including a resonator cavity and a resonator tube, characterized in that it additionally contains a source of gas oscillations, including an elastic membrane installed with the ability to create gas oscillations in the resonator, and a device for generating membrane oscillations. 2. Pulsed resonator ejector according to claim 1, characterized in that the device for generating membrane oscillations is made in the form of an electric motor and a crank mechanism.

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