Aerodynamic noise jet noise reduction system for high-speed trains

Abstract

The present application relates to a kind of high-speed train aerodynamic noise jet noise reduction system, including the arrangement of the position of jet air collection port and jet nozzle position, the air required for jet is collected in the front end surface of barrier, air is automatically collected using train front movement, air is transmitted to nozzle and sprayed after passing through internal cavity, jet nozzle is distributed in the leading edge position of bogie cavity, including barrier bottom and car body side two parts.Jet is interfered with the shedding of train surface shear layer after spraying, makes the high-speed shear layer far away from bogie, to form low-speed zone in bogie area, prevent high-speed airflow from directly impacting rear bogie and its chamber surface to reduce its surface aerodynamic sound source.Compared with prior art, the present application can effectively and economically reduce the aerodynamic noise generated by bogie area during train operation, while having the advantages of not increasing additional weight, safe and reliable, without additional power source etc..

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aerodynamic noise, and relates to a system capable of reducing aerodynamic noise of a high-speed train, in particular to arrangement of a jet nozzle and a gas collection port. BACKGROUND

[0002] At present, noise reduction of aerodynamic noise generated in the bogie area of a high-speed train is an international and domestic difficult problem. Common noise reduction measures include modifying the structure of the bogie chamber and installing sound-absorbing materials inside it. However, the existing noise reduction methods usually bring other additional problems. For example, baffle plates are installed on the sides and bottom of the chamber to isolate the impact of high-speed airflow on the internal components to reduce the aerodynamic sound source, but since the two sides of the train are isolated, the potential risks during train operation, such as rollover, are increased, and it is not conducive to the observation of the bogie operation by the staff. Furthermore, although sound-absorbing materials can be installed inside the bogie chamber to absorb part of the sound energy, the sound-absorbing materials increase the weight of the train, thereby increasing the operating cost; at the same time, due to the complex train operating environment, the surface of the sound-absorbing materials is easily blocked by dust and other impurities, and it is difficult and costly to maintain them.

[0003] Patent application CN201811606540.9 discloses a high-speed train aerodynamic noise reduction system and method, which includes a signal collector, a controller and two air gun generating devices; the signal collector is connected with the controller, and the controller is also connected with the two air gun generating devices; each air gun generating device includes an air flow emitter, a total air flow guide pipe, a first booster and a second booster, each booster is connected with the air inlet of the air flow emitter through the total air flow guide pipe; the first booster and the second booster are connected with the controller. Based on the interference ability of air jet to the boundary layer, combined with the aerodynamic characteristics during the running of the high-speed train, without changing the shape and material of the train, through the active noise reduction system, the aerodynamic characteristics of the train are improved, and the comfort, safety and energy saving of the train are improved. However, the aerodynamic noise generated by the boundary layer of the train body is not the main sound source, and the pertinence is not strong; the airflow flow required to interfere with the separation zone of the train head and the train tail is huge, and additional equipment is needed to collect the airflow; the additional equipment such as the booster increases the weight of the train, thereby increasing the operating cost.

[0004] Patent application CN202111645561.3 discloses a high-speed train pantograph cavity aerodynamic noise reduction system based on intelligent jet. The system includes a central control mechanism and a gas intelligent jet generating mechanism. The gas intelligent jet generating mechanism comprises a high-pressure gas source, a proportional pressure regulating valve, a pressure sensor, a proportional gas flow valve, a flow sensor, and an injector, all connected sequentially via gas pipelines. The injector's nozzle is located on the leeward side of the pantograph cavity. The proportional pressure regulating valve, pressure sensor, proportional gas flow valve, and flow sensor are electrically connected to the central control mechanism. This noise reduction system is an active noise reduction system. By installing the injector on the leeward side of the pantograph cavity and injecting gas there, the system alters the shear layer above the pantograph cavity through a gas jet, reducing the collision between the shear layer and the cavity's rear wall, thereby reducing aerodynamic noise in the pantograph cavity and achieving noise reduction. However, since the patented airflow is ejected perpendicular to the front wall of the cavity, the required gas flow rate is large due to the noise reduction principle and nozzle shape, which increases the difficulty of gas supply; secondly, due to the excessive flow rate, the high-pressure airflow itself will become a sound source, thereby reducing the noise reduction effect; and the addition of complex gas source and control equipment increases the weight and maintenance cost of the train, thereby increasing the operating cost of the train. Summary of the Invention

[0005] The purpose of this invention is to provide a high-speed train aerodynamic noise jet noise reduction system in order to overcome the defects of the prior art.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A high-speed train aerodynamic noise jet noise reduction system is provided, wherein a jet air collection port is set at the front of the high-speed train to automatically collect air using the forward motion of the train; jet nozzles are distributed at the leading edge of the bogie cavity; and the jet collection port and the jet nozzles are connected by an airflow passage.

[0008] Furthermore, the jet air collection port is located on the front face of the obstacle clearer or other front of the vehicle that can directly face the incoming airflow, including the nose of the vehicle and the area below the nose.

[0009] Furthermore, the jet nozzles are located at the bottom of the obstacle clearer and on the side of the vehicle body.

[0010] Furthermore, the jet nozzle is provided in multiple rows, arranged in single, double, or multiple rows.

[0011] Furthermore, the jet nozzle is rectangular in shape, with a width of 10-30 mm, preferably 20 mm, and the spacing between adjacent jet nozzles is 30-60 mm, preferably 50 mm.

[0012] Further, the multiple jet nozzles are arranged in a straight line or staggered.

[0013] Further, the air outlet angle of the jet nozzles is perpendicular to the surface of the train or is deflected at an angle of 15-65 degrees with respect to the direction of the incoming flow.

[0014] Further, the jet air collection port is formed by a cutout on the windward surface of the front end of the fender, and the area of the cutout accounts for 50-70% of the area of the front end surface of the fender.

[0015] Further, the jet air collection port is connected to an air flow passage inside the fender, and the air flow is ejected from the jet air collection port through the air flow passage.

[0016] Further, the area ratio between the jet air collection port and the jet nozzle is 1.2-1.3:1. Due to the same mass flow, the flow velocity of the air flow at the jet air collection port is smaller than the flow velocity of the air flow ejected from the jet nozzle. The selected placement position of the nozzle has a smaller hydrostatic pressure, and the pressure difference between the total pressure of the inlet, i.e., the sum of the static pressure and the dynamic pressure head, and the pressure loss caused by the air flow passage, so that the pressure ratio maintained when the air flow reaches the jet nozzle allows the air flow to be ejected at a speed close to the running speed of the train.

[0017] The present application collects the high-speed air flow at the front of the train and ejects it from the nozzle located at the front edge of the bogie chamber, thereby forming a low-speed area around the bogie chamber by interfering with the development of the shear layer, avoiding the direct collision of the high-speed shear layer with the bogie components, and reducing the noise source.

[0018] The present application ingeniously utilizes the forward power of the train to collect the high-speed air flow relative to the train and eject it from the jet nozzle. By ingeniously arranging the nozzle position, the purpose of interfering with the shedding shear layer is achieved.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1. High-efficiency noise reduction and good use effect: ingeniously through the staggered arrangement of the nozzles, the single-column jet noise reduction effect can be increased, and through the multi-column arrangement, the noise reduction effect can be further enhanced. From the perspective of reducing the aerodynamic sound source, the air flow speed in the bogie area is reduced, and the generation of aerodynamic noise is fundamentally reduced.

[0021] 2. No additional weight: the air flow collection and ejection device are realized by opening on the surface of the train, the air flow is transmitted through the train fender and the head cavity, and the transmission power is provided by the pressure formed at the air collection port when the train runs forward. No additional components are needed, thereby reducing the weight.

[0022] 3. Easy maintenance: due to the absence of additional components, there is no need for excessive maintenance, and the service life is long.

[0023] 4. Safe and reliable: due to no additional components, there is almost no potential interference to the safe operation of the train.

[0024] 5. Low operating cost: the present application does not require excessive maintenance, and no additional energy is provided, thereby reducing the operating cost. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 a schematic diagram of the position of the jet air collection port of the present application;

[0026] Figure 2 a schematic diagram of the structure of the jet air collection port of the present application.

[0027] Figure 3 a schematic diagram of the position of the side surface of the jet nozzle of the present application.

[0028] Figure 4 a schematic diagram of the position of the bottom surface of the jet nozzle of the present application.

[0029] Figure 5 a schematic diagram of the structure of the jet nozzle of the present application.

[0030] Figure 6 a schematic diagram of the air flow from the air collection port to the jet nozzle of the present application.

[0031] Reference signs shown in the drawings:

[0032] 1. Jet air collection port

[0033] 101. Front panel of the snowplow, 102. Air collection port;

[0034] 2. Jet nozzle

[0035] 201. Jet plate, 202. Jet nozzle.

[0036] 3. Air flow passage. DETAILED DESCRIPTION

[0037] The technical solutions of the present application will be further described clearly and completely in combination with the drawings and examples.

[0038] Examples

[0039] A high-speed train aerodynamic noise jet noise reduction system, comprising the arrangement of the position of the jet air collection port 1 and the position of the jet nozzle 2. The required air for the jet is collected at the front end of the snowplow, and the air is automatically collected by the forward motion of the train. The jet air collection port 1 can be located at the front end of the snowplow or other positions of the car head that can directly face the airflow, including the car nose and the area near the car nose. The jet nozzle 2 is distributed at the front edge position of the bogie cavity, including the bottom of the snowplow and the side of the car body. The air flow passage 3 is located inside the snowplow.

[0040] AsFigure 1 As shown in the figure, the air required by the jet flow is collected at the front end surface of the deflector, and the front panel 101 of the deflector is provided with an air collection port 102, which has an area of 60-70% of the area of the front panel 101 of the deflector. Figure 3 and Figure 4 As shown in the figure, the jet flow nozzles 2 are distributed at the front edge of the bogie chamber, that is, the front edge of the bogie chamber is used as a jet flow plate 201, and a plurality of jet flow nozzles 202 are provided on the jet flow plate 201. Figure 5 As shown in the figure, the plurality of jet flow nozzles 202 can include linear arrangement and staggered arrangement, and the number of nozzle columns can be single column, double column, and multiple columns, etc. In the embodiment, the width of the jet flow nozzle 202 is 10-30mm, and the distance between the two jet flow nozzles 202 is 40-60mm. Figure 6 As shown in the figure, the gas flow path 3 is located inside the deflector and connects the air collection port 1 and the jet flow nozzle 2. When the train moves forward at high speed, the airflow enters the airflow passage 3 through the air collection port 102, and then reaches the position of the jet flow nozzle 2. Due to the principle of conservation of mass, the air entering the airflow passage 3 is equal to the mass of the fluid ejected from all jet flow nozzles 202, and the ejected airflow is ejected outward at a speed close to the running speed of the train and interferes with the shear layer on the surface of the train, forming a low-speed area in the bogie area, reducing the intensity of the aerodynamic sound source and thus reducing the aerodynamic noise. For example, when the train runs at a speed of 300km / h, the sound power emitted by the bogie near the train head is 133dB, and after adding the system, the sound power emitted is 127dB, and the noise is reduced by 6dB. The air required by the jet flow is collected at the front end surface of the deflector by the jet flow air collection port 1, and the air is automatically collected by the forward motion of the train. The collected air is transmitted through the internal cavity to the jet flow nozzle 2 for ejection. Three-dimensional numerical calculation and experimental research show that due to the viscous effect of the airflow, a shear layer will be formed on the surface of the train. After the jet flow is ejected vertically to the surface of the train, an airflow barrier will be formed on the surface of the train, which hinders the forward development of the shear layer and pushes it away from the surface of the train. The high-speed shear layer that falls off will deflect outward, thereby preventing the high-speed airflow from reaching the bogie area and forming a low-speed area with a speed lower than the main flow area, preventing the high-speed airflow from directly impacting the rear bogie and the surface of the chamber to reduce the surface aerodynamic sound source.

[0041] The present application can effectively reduce the aerodynamic noise generated by the bogie area during the running of the train, and has the advantages of not increasing additional weight, being safe and reliable, and not requiring an additional power source.

Claims

1. A high-speed train aerodynamic noise jet noise reduction system, characterized in that, The jet air collecting port (1) is arranged on the head of the high-speed train, and the air is collected automatically by the movement of the train; the jet nozzles (2) are arranged on the front edge of the bogie cavity; the jet nozzles (2) are arranged in single, double or multiple columns, and are formed by the cutouts on the surface of the train body, and have a rectangular shape with a width of 10-30 mm and a spacing of 30-60 mm between adjacent jet nozzles (2); the jet nozzles are arranged in a straight line or staggered, and the air outlet angle of the jet nozzles (2) is perpendicular to the surface of the train or is deflected at an angle of 15-65 degrees to the flow direction; The jet air collecting port (1) is formed by the cutout on the windward surface of the front end of the fender, and has an area of 50-70% of the area of the front end of the fender; the collected air flow is discharged through the air flow passage (3) and the jet nozzles (2); The flow velocity of the air flow at the jet air collecting port (1) is less than the flow velocity of the air flow discharged from the jet nozzles (2), the fluid static pressure at the selected position of the jet nozzles (2) is small, the pressure difference between the total pressure of the inlet, i.e. the sum of the static pressure and the dynamic pressure head, and the partial pressure loss is balanced, and the pressure ratio maintained when the air flow reaches the jet nozzles (2) allows the air flow to be discharged at a speed close to the running speed of the train.

2. The aerodynamic noise jet noise reduction system of a high-speed train according to claim 1, characterized in that, The jet air collecting port (1) is located on the front end of the fender or other positions of the train head that can directly face the air flow, including the nose and the area near the bottom of the nose.

3. The system of claim 1, wherein the system is configured to reduce the aerodynamic noise of a high-speed train. The jet nozzles (2) are arranged on the bottom of the fender and the side of the train body.

4. The system of claim 1, wherein, The area ratio between the jet air collecting port (1) and the jet nozzles (2) is 1.2-1.3:1.

Images