RU2534639C2 - Noise suppression method - Google Patents

Abstract

FIELD: physics, acoustics.

SUBSTANCE: method is intended for suppressing noise in a moving gas stream. In the method, a gas stream at an audio frequency characterised by a certain pressure amplitude value, in a stack of ribbon coils, is broken by the spirals into separate streams with the same direction of rotation, which interact with each other and the surface of the spirals to maintain a common direct flow direction. Active forced dissipation of pressure energy, accompanied by accelerated reduction of frequency of sound vibrations, occurs.

EFFECT: high efficiency of suppressing noise while reducing material consumption and making production easier.

6 cl, 3 dwg

Description

1. FIELD OF THE INVENTION

The invention relates mainly to the engineering industry.

2. BACKGROUND

There are many known solutions to reduce noise from moving gas streams. As an analogue of the proposed method for damping noise, the method adopted in the muffler is adopted, the element of which is spiral inserts installed in series inside the pipe, with different pitch and opposite directions of twist (patent RU 2059838). The disadvantage of this solution is the lack of efficiency of using a single spiral.

3. SUMMARY OF THE INVENTION.

The claimed invention A METHOD FOR SILENCING NOISE is intended to increase the efficiency of damping noise of gas flows by using packages of tape spirals, i.e. tapes twisted around their longitudinal axes.

The essence of the proposed method of damping noise is that a gas stream characterized by certain values of frequency and pressure amplitude in a packet of tape spirals is preferably of the same rotation and preferably of a dense packing scheme (triangle) is divided by spirals into separate rotating flows interacting with each other and the surfaces of the spirals with maintaining the general direct flow direction. In this case, active (forced) dissipation (dissipation) of the pressure energy (amplitude) of the flow occurs, accompanied by an accelerated decrease in the frequency of sound vibrations, while simultaneously contributing to a sharp decrease in the noise level.

The technical result of the claimed invention is to increase the efficiency of damping noise with a decrease in material consumption and laboriousness of manufacture, as well as an increase in the useful power of internal combustion engines.

4. BRIEF DESCRIPTION OF THE DRAWINGS.

The sketches below show:

FIG. 1 is a diagram of the interaction of gas flows in a package of spirals;

FIG. 2 - the proposed installation scheme of the package of spirals;

FIG. 3 - a fragment of a layer of a spiral nozzle.

5. The implementation of the invention.

FIG. 1, 2 - cross sections of a packet of spirals with the arrows indicated by the direction of rotation of the flows and the placement of the packet (1) relative to the arrows indicated by the passage of the gas stream gives an idea of the mechanism of the method of damping noise. From a packet of spirals, gases can additionally pass through a dissipation chamber (2) and exit into the atmosphere.

Given the low drag of the tape spiral, the smoothness of the curvature of its surface and the large coefficient of free section of the packet (more than 90% when the ratio of the thickness of the tape to its width is less than 0.1), as well as the fact that the flow energy will be spent mainly on the rotation and interaction of the rotating flows (forced dissipation), one should expect a low resistance of the package, low material consumption and the complexity of manufacturing. A package of spirals can be installed both on the intake side and on the exhaust side of internal combustion engines. These design features contribute to an increase in the effective power of the engines, as well as an increase in the continuous run of the package.

Packages of spirals can be of various configurations in the cross section, including options with unfilled zones inside the cross section of the packet.

The package can be assembled from layers of variable spirals (for a fragment of the layer, see FIG. 3), according to patent RU 2289473. The essence of the method of manufacturing spiral layers is that the elements of the layer — two coaxial one-piece spirals of opposite rotation with a bend of up to 90 ° —are obtained by deformation of the sheets simultaneously perforation and flanging on opposite sides of the sheet with perforating and flanging elements. The spiral layers for forming the bag can be twisted around the axis of the flow.

Spiral bags can be made of materials with catalytic properties for neutralizing exhaust gases, or coated with substances with such properties, which greatly simplifies the system for cleaning and damping exhaust noise and also reduces the material consumption and laboriousness of its manufacture.

The package is used as an element in silencers of noise from moving gas streams. The optimality of the package for a specific characteristic of the gas flow depends on the design parameters of the spiral: the width and thickness of the tape, the module (the ratio of the width of the tape to the length of the spiral with a rotation of 360 °), its length and configuration of placement in the package, as well as on setting the level of noise suppression.

Claims (6)

1. A method of damping noise, characterized in that a gas stream with certain values of frequency and pressure amplitude in a packet of tape spirals is preferably of the same rotation and preferably of a dense packing scheme (triangle) is divided by spirals into separate rotating flows interacting with each other and the surfaces of the spirals while maintaining the common direct flow direction. 2. The method of damping noise according to claim 1, characterized in that the package of spirals can be installed both on the inlet side and on the exhaust side of internal combustion engines. 3. The method of damping noise according to claim 1, characterized in that the package of spirals can be of various configurations in cross section, including options with unfilled zones inside the cross section of the package. 4. The method of damping noise according to claim 1, characterized in that the packet of spirals can be assembled from layers of variable spirals obtained by deformation of the sheets by simultaneous cutting and flanging and which can be twisted around the axis of the flow to form a packet. 5. The method of damping noise according to claim 1, characterized in that the package of spirals can be made of materials having catalytic properties for neutralizing exhaust gases, or coated with substances with such properties. 6. The method of damping noise according to claim 1, characterized in that the packet of spirals is used as an element in silencers of noise from moving gas streams.

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