Noise reduction air inlet bypass recirculation structure of air compressor

Abstract

The invention discloses a noise reduction air inlet bypass recirculation structure of an air compressor, and particularly relates to the technical field of air inlet structures of superchargers, the noise reduction air inlet bypass recirculation structure comprises an air inlet pipe and an air inlet bypass recirculation annular sleeve, the air inlet pipe is fixedly sleeved with the air inlet bypass recirculation annular sleeve, and the air inlet bypass recirculation annular sleeve comprises an inner ring and an outer ring; the inner ring is sleeved with the outer ring, an annular sealing cavity is formed between the inner ring and the outer side wall of the air inlet pipe, an annular cavity is formed among the outer side wall of the air inlet pipe, the outer side wall of the inner ring and the inner side wall of the outer ring, a bypass air inlet and a bypass air outlet which are communicated with the annular cavity are formed in the side wall of the air inlet pipe, and the bypass air inlet is close to the air outlet of the air inlet pipe. The bypass gas outlet is close to the gas inlet of the gas inlet pipe, the side wall of the end, away from the gas inlet pipe, of the inner ring can elastically deform, and the annular sealing cavity is filled with gas with certain pressure. Noise reduction can be carried out on discrete single sound of the gas compressor at different rotating speeds, and potential hazards of normal operation of equipment are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of an air intake structure of a supercharger, and in particular to a noise-reducing air intake bypass recirculation structure of an air compressor. Background Art

[0002] In recent years, in order to meet the requirements of high power and high economy of modern internal combustion engines, especially the requirements of supercharged diesel engines for transport and engineering machinery to maintain sufficient boost pressure in a wide range of speed and load to obtain satisfactory low-speed performance, the matching supercharger compressor must have a wide stable working range while having high efficiency, especially at low flow rates, requiring a higher pressure ratio. In this way, the surge line of the compressor must move toward the direction of low flow. The use of a compressor intake bypass recirculation system is an effective technical measure to broaden the stable working range of the compressor at low flow rates, and it has been widely used.

[0003] With the advancement of design technology, turbochargers are constantly developing towards large flow and high pressure ratio, and the noise problem of turbochargers is becoming increasingly prominent. A large number of studies have confirmed that the sound pressure level frequency of the compressor's aerodynamic noise is high and is one of the main noise sources of the turbocharger. Therefore, reducing the aerodynamic noise of the compressor can effectively reduce the overall noise of the turbocharger. One of the main ways to reduce noise is to control the noise in the noise propagation path. At present, the method of installing a muffler is mostly used to reduce noise, and there are few measures to reduce noise by changing the structure of the compressor intake pipe. The main contribution of centrifugal compressor aerodynamic noise comes from discrete single-tone noise, and its frequency is closely related to the compressor speed. In the actual operation of the diesel engine, different situations require the compressor to work at different speeds, and currently there are few studies that consider the compressor intake pipe structure for noise reduction at different speeds. Summary of the invention

[0004] The purpose of the present invention is to provide a noise-reducing intake bypass recirculation structure for a compressor to solve the problems existing in the above-mentioned prior art, and to be able to reduce the noise of discrete single sounds of the compressor at different speeds, reduce potential hidden dangers in the normal operation of the equipment, and be beneficial to the normal work and life of the staff.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a noise reduction intake bypass recirculation structure of a compressor, comprising an intake pipe and an intake bypass recirculation annular sleeve, the intake bypass recirculation annular sleeve being fixedly sleeved outside the intake pipe, the intake bypass recirculation annular sleeve comprising an inner ring and an outer ring, the outer ring being sleeved outside the inner ring, a hollow annular sealed chamber being formed between the inner ring and the outer wall of the intake pipe, a hollow annular chamber being formed between the outer wall of the intake pipe, the outer wall of the inner ring and the inner wall of the outer ring, a bypass inlet and a bypass outlet being provided on the side wall of the intake pipe, the bypass inlet and the bypass outlet being both connected to the annular chamber, the inner ring being located between the bypass inlet and the bypass outlet, the bypass inlet being close to the intake pipe outlet, the bypass outlet being close to the intake pipe inlet, the side wall of the inner ring at an end away from the intake pipe being able to undergo elastic deformation, and the annular sealed chamber being filled with gas at a certain pressure.

[0007] Preferably, it also includes an air inlet pipe flange, and the air inlet pipe flange is fixedly connected to one end of the air inlet pipe outlet.

[0008] Preferably, the axis of the air intake pipe, the axis of the inner ring and the axis of the outer ring are collinear.

[0009] Preferably, the gas is nitrogen.

[0010] Preferably, the bypass air inlet and the bypass air outlet are both circular ring-shaped openings.

[0011] Preferably, the opening width of the bypass air inlet is the same as the opening width of the bypass air outlet.

[0012] Preferably, a plurality of connecting struts are provided on the circumference of the bypass air outlet, and the connecting struts are used to fix one end of the air inlet of the air inlet pipe with the middle part of the air inlet pipe.

[0013] Preferably, the plurality of connecting struts are evenly arranged along the circumference of the air intake pipe.

[0014] Preferably, the side wall of the inner ring at one end away from the air inlet pipe is an elastic circular ring film.

[0015] Preferably, the two side walls of the inner ring connected to the air intake pipe are made of hard material.

[0016] Compared with the prior art, the present invention has achieved the following technical effects:

[0017] The present invention provides a noise reduction intake bypass recirculation structure for a compressor. The aerodynamic noise generated by the compressor is transmitted into an annular chamber through a bypass air inlet and then transmitted out from a bypass air outlet. At the bypass air outlet, the sound waves from the annular chamber and the sound waves from the air inlet pipe will interfere with each other destructively, and the stroke difference between the two sound waves is continuous within a range, so that the noise reduction effect on wide-band noise including discrete single-tone noise frequency can be achieved; and the working speed of the centrifugal compressor in the diesel engine is variable, and the discrete single-tone noise frequency corresponding to each speed is different. The pressure of the airflow in the annular chamber is different at different speeds, while the air pressure inside the annular sealing chamber is constant, so that the side wall of the end of the inner ring away from the air inlet pipe will deform differently at different speeds, so as to change the stroke of the sound wave in the annular chamber, so as to achieve the purpose of destructive interference of the discrete single-tone noise corresponding to different speeds, and achieve the effect of reducing the discrete single-tone noise of the compressor at different speeds. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 The schematic diagram of the structure of the noise reduction intake bypass recirculation structure of the compressor in the following case;

[0020] Figure 2 The acoustic wave travel diagram of the noise reduction intake bypass recirculation structure of the compressor in the following case;

[0021] Figure 3 is a structural schematic diagram of a noise reduction intake bypass recirculation structure of a compressor under situation 2;

[0022] Figure 4 The acoustic wave travel diagram of the noise reduction intake bypass recirculation structure of the compressor in case 2;

[0023] Figure 5 Schematic diagram of the structure of the noise reduction intake bypass recirculation structure of the compressor under situation three;

[0024] Figure 6 This is the sound wave travel diagram of the noise reduction intake bypass recirculation structure of the compressor under situation three.

[0025] In the figure: 1-intake pipe; 2-outer ring; 3-inner ring; 4-annular sealing chamber; 5-annular chamber; 6-bypass air inlet; 7-bypass air outlet; 8-intake pipe inlet; 9-intake pipe outlet; 10-intake pipe flange; 11-connecting support. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The purpose of the present invention is to provide a noise-reducing intake bypass recirculation structure for a compressor to solve the problems existing in the above-mentioned prior art, reduce the noise generated by the compressor, reduce potential hidden dangers in the normal operation of the equipment, and facilitate the normal work and life of the staff.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The present invention provides a noise reduction intake bypass recirculation structure of a compressor, such as Figure 1-6As shown, it includes an intake pipe 1 and an intake bypass recirculation annular sleeve, the intake bypass recirculation annular sleeve is fixedly sleeved outside the intake pipe 1, the intake bypass recirculation annular sleeve includes an inner ring 3 and an outer ring 2, the outer ring 2 is sleeved outside the inner ring 3, a hollow annular sealed chamber 4 is formed between the inner ring 3 and the outer wall of the intake pipe 1, a hollow annular chamber 5 is formed between the outer wall of the intake pipe 1, the outer wall of the inner ring 3 and the inner wall of the outer ring 2, a bypass air inlet 6 and a bypass air outlet 7 are opened on the side wall of the intake pipe 1, the bypass air inlet 6 and the bypass air outlet 7 are both connected to the annular chamber 5, the inner ring 3 is located between the bypass air inlet 6 and the bypass air outlet 7, the bypass air inlet 6 is close to the intake pipe outlet 9, the bypass air outlet 7 is close to the intake pipe inlet 8, the side wall of the inner ring 3 away from the intake pipe can undergo elastic deformation, and the annular sealed chamber 4 is filled with gas under a certain pressure. One side of the air inlet pipe outlet 9 is a high-pressure environment, and one side of the air inlet pipe inlet 8 is a low-pressure environment. The airflow flows from the high-pressure side to the low-pressure side. Therefore, a bypass air inlet 6 is set on the side close to the air inlet pipe outlet 9. The airflow generated by the compressor is introduced into the annular chamber 5 through the bypass air inlet 6, flows out from the bypass air outlet 7 after passing through the annular chamber 5, and then flows to the impeller again for pressurization. At the bypass air outlet 7, the sound waves from the annular chamber 5 and the sound waves from the air inlet pipe 1 will destructively interfere, and the stroke difference of the two beams of sound waves is continuous within the range, so it is possible to achieve the sound wave interference containing discrete single-tone noise. The noise reduction effect of wide-band noise including the rate is achieved; and the working speed of the centrifugal compressor in the diesel engine is variable, the discrete single-tone noise frequency corresponding to each speed is different, the pressure of the air flow in the annular chamber 5 is different at different speeds, and the air pressure inside the annular sealing chamber 4 is constant, so that the side wall of the end of the inner ring 3 away from the intake pipe will undergo different deformations at different speeds, thereby changing the propagation path of the sound wave in the annular chamber 5, so as to achieve the purpose of destructive interference of the discrete single-tone noise corresponding to different speeds, and realize the effect of noise reduction of the discrete single-tone noise of the compressor at different speeds.

[0030] It is further preferred in the embodiment of the present invention that the noise reduction intake bypass recirculation structure of the compressor further includes an intake pipe flange 10 , and the intake pipe flange 10 is fixedly connected to one end of the intake pipe outlet 9 .

[0031] It is further preferred in the embodiment of the present invention that the axis of the air intake pipe 1 , the axis of the inner ring 3 and the axis of the outer ring 2 are collinear.

[0032] In the embodiment of the present invention, it is further preferred that the gas is nitrogen or other gas with a certain pressure and a large acoustic impedance. Gas with a large acoustic impedance can serve as an effective acoustic barrier.

[0033] It is further preferred in the embodiment of the present invention that the bypass air inlet 6 and the bypass air outlet 7 are both circular openings, and the opening width of the bypass air inlet 6 is the same as the opening width of the bypass air outlet 7 .

[0034] It is further preferred in the embodiment of the present invention that a plurality of connecting struts 11 are provided in the circumferential direction of the bypass air outlet 7, the connecting struts 11 are used to fix one end of the air inlet of the air intake pipe with the middle part of the air intake pipe, and the plurality of connecting struts 11 are evenly arranged along the circumference of the air intake pipe.

[0035] In the embodiment of the present invention, it is further preferred that the side wall of the inner ring 3 at one end away from the intake pipe is an elastic annular film or other elastic element that can deform differently with different pressures. When the compressor speed changes, the pressure on the outside of the annular film will also change. The annular film can produce different deformations as the gas pressure in the annular chamber 5 changes, thereby affecting the path of sound propagation inside the intake bypass recirculation cavity, so that the variable air cavity structure can achieve noise reduction effects at different speeds. Specifically, there are three typical situations: In the first situation, the gas pressure in the annular chamber 5 is the same as the pressure in the annular sealing chamber 4, and the annular film does not deform; in the second situation, the gas pressure in the annular chamber 5 is greater than the pressure in the annular sealing chamber 4, and the annular film bends and deforms inwards; in the third situation, the gas pressure in the annular chamber 5 is less than the pressure in the annular sealing chamber 4, and the annular film bends and deforms outwards. In the three cases, the stroke of the sound wave 2 in the annular chamber 5 is different, while the stroke of the sound wave 1 is constant. Therefore, the stroke difference between the two sound waves at the bypass outlet 7 changes with the compressor speed, so that the suppressed noise frequency band changes with the compressor speed.

[0036] Assume that the compressor has three speeds: speed 1, speed 2 and speed 3. At speed 1, the variable air cavity structure corresponds to case 1, at speed 2, the variable air cavity structure corresponds to case 2, and at speed 3, the variable air cavity structure corresponds to case 3. The discrete single-tone noise frequency at speed 1 is λ1, the discrete single-tone noise frequency at speed 2 is λ2, and the discrete single-tone noise frequency at speed 3 is λ3. In cases 1, 2 and 3, the travel of sound wave 2 in the intake bypass recirculation structure cavity is d 21 ,d 22 ,d 23 , the distance traveled by sound wave 1 in the intake pipe is d1.

[0037]

[0038] n is an integer (0, 1, 2, ...), and its physical meaning is to mark the frequency at which destructive interference occurs. Each integer corresponds to a specific stroke difference condition, thereby determining the frequency band in which the sound waves cancel each other out in space. The pressure in the sealing chamber and the material of the annular film can be reasonably obtained through experiments or simulations. As long as the stroke difference between the two columns of sound waves at each speed satisfies this formula, the two columns of sound waves will interfere destructively, and the noise reduction effect can be achieved for discrete single-tone noise at different speeds. The present invention changes the stroke (d2) of the sound waves in the intake bypass recirculation chamber by changing the speed of the compressor, and the change in speed itself will cause the wavelength (λ) to change, and finally continuously satisfy this formula, thereby achieving an adaptive passive control noise reduction effect.

[0039] It is further preferred in the embodiment of the present invention that the two side walls of the inner ring 3 connected to the intake pipe 1 are made of hard material, and when the gas pressure in the annular chamber 5 changes, the deformation of the two side walls of the inner ring 3 connected to the intake pipe 1 is small.

[0040] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A noise reduction intake bypass recirculation structure for a compressor, characterized in that: The vent pipe has an inner wall that is provided with a vent for venting the intake air, and an outer wall that is provided with a vent for venting the intake air.

2. The noise reduction intake bypass recirculation structure of the compressor according to claim 1, characterized in that: It also includes an air inlet pipe flange, which is fixedly connected to one end of the air inlet pipe outlet.

3. The noise reduction intake bypass recirculation structure of the compressor according to claim 1, characterized in that: The axis of the air intake pipe, the axis of the inner ring and the axis of the outer ring are collinear.

4. The noise reduction intake bypass recirculation structure of the compressor according to claim 1, characterized in that: The gas is nitrogen.

5. The noise reduction intake bypass recirculation structure of the compressor according to claim 1, characterized in that: The bypass air inlet and the bypass air outlet are both circular ring-shaped openings.

6. The noise reduction intake bypass recirculation structure of the compressor according to claim 5, characterized in that: The opening width of the bypass air inlet is the same as the opening width of the bypass air outlet.

7. The noise reduction intake bypass recirculation structure of the compressor according to claim 5, characterized in that: A plurality of connecting struts are arranged on the circumference of the bypass air outlet, and the connecting struts are used to fix one end of the air inlet of the air inlet pipe with the middle part of the air inlet pipe.

8. The noise reduction intake bypass recirculation structure of the compressor according to claim 7, characterized in that: The plurality of connecting struts are evenly arranged along the circumference of the air intake pipe.

9. The noise reduction intake bypass recirculation structure of the compressor according to claim 1, characterized in that: The side wall of the inner ring at one end away from the air inlet pipe is an elastic circular ring film.

10. The noise reduction intake bypass recirculation structure of the compressor according to claim 9, characterized in that: The two side walls of the inner ring connected to the air intake pipe are made of hard material.

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