319 results about "Helmholtz resonator" patented technology

An incubator can include a body, a bed supported by the body, and a canopy defining an interior chamber that includes the bed. The incubator can include any combination of various features configured to reduce sound energy inside the incubator. The incubator can include a passive radiator, a Helmholtz resonator, a meta material absorber, an active noise cancelation system, a vented door latch assembly, an acoustically permeable seal, a pressure relief valve, a lift mechanism that uses a belt drive, double paned canopy walls, a bin with insulating compliant elements, a manual pressure release valve, a pressure differential notification system, non-parallel or curved canopy walls, a mattress with reticulated foam, and / or an acoustic filter.

The technology described herein is directed towards one or more modular metasurfaces arranged with unit cells for sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. The metasurfaces can be arranged in a modular frame structure of surrounding unit cells, positioned behind the server's fan(s), with an opening in the frame structure to facilitate airflow therethrough, without obstructing or substantially obstructing the airflow to the surrounding environment.

The technology described herein is directed towards modular metasurfaces arranged with unit cells for narrowband, wideband and / or multiband sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed in a server rack, proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Differently-dimensioned unit cells can be built into a single metasurface module, thereby facilitating wideband and / or multiband sound absorption with that metasurface. The modular metasurfaces can be attached to the sidewalls of a server rack, or positioned in otherwise empty slots above and below a server, optionally coupled to blanking panels for covering the openings of those slots.

The invention discloses a bionic TENG sensor unit for an artificial throat and a preparation method thereof, and relates to the field of artificial throats, and the sensor unit comprises a gradient micro-dome friction layer, a strain amplification layer, an electrode layer and a back cavity substrate layer. The gradient micro-dome array realizes gradual contact through gradient change of height and diameter; the strain amplification layer converts vertical vibration into horizontal strain by using a cantilever beam-sliding block structure; the back cavity array selectively amplifies vibration at a specific frequency based on the Helmholtz resonance principle. The invention further provides a corresponding preparation method. The preparation method comprises the steps of back cavity forming, electrode deposition, microstructure manufacturing, surface treatment and the like. The sensor has the advantages of high sensitivity, good frequency selectivity and strong durability, and is particularly suitable for detecting weak laryngeal vibration signals of laryngeal patients.

The multifunctional acoustic device is formed by periodically arranging unit cells in the horizontal direction, and each unit cell comprises an upper frame body, a lower frame body and a vibration absorption sandwich layer located between the upper frame body and the lower frame body; the upper frame body is provided with a through hole; the vibration absorption sandwich layer comprises a central cantilever beam located at the transverse center position, a sandwich plate surrounding the periphery of the central cantilever beam and fixed between the upper frame body and the lower frame body, and vibrator mass blocks arranged above and below the central cantilever beam; the sandwich plate is connected with the central cantilever beam through a plurality of L-shaped beams; and the plurality of L-shaped beams surround the periphery of the central cantilever beam. The lattice sandwich structure is used as a basic frame, a local resonance system with a spring mass part is formed, a sub-wavelength elastic wave band gap frequency band is obtained, a low-frequency vibration reduction effect is generated, holes are formed in the upper frame body, the remaining part in the structure is used as an air spring, a Helmholtz resonant cavity is formed, and meanwhile low-frequency vibration reduction and broadband sound absorption are achieved.

The technology described herein is directed towards a metasurface arranged with unit cells for broadband and / or multiband sound absorption, in which the unit cells are based on the principles of Helmholtz resonators. Deeply subwavelength sound absorbing unit cells are designed and constructed based on desired resonance frequencies. Each unit cell includes a neck portion and air chamber dimensioned to resonate at a desired resonance frequency and thereby inverse phase cancel corresponding frequencies of incoming sound waves. Differently designed and arranged subgroups of unit cells are part of the metasurface, which can be positioned proximate to a noise source. As practical examples, the metasurface or multiple metasurfaces can be placed near or wrapped around a computer server or rack of servers to absorb fan noise. The metasurface components (including the unit cells) can be printed by a 3D printer to result in a thin, light-weight, and cost effective noise absorbing metasurface.

The invention relates to the technical field of noise control, and discloses a combined noise reduction and sound absorption unit and a sound absorption board, sound absorption unit structures are periodically arranged and combined to form the sound absorption board with a large area, the sound absorption board is installed on an indoor wall or ceiling of a gas power plant, and indoor low-frequency broadband sound absorption and noise reduction are achieved. The sound absorption device comprises a first sound absorption assembly, the first sound absorption assembly comprises a first shell and a first micro-perforated plate arranged on the first shell, and the first micro-perforated plate is arranged on the first shell; the second sound absorption assembly comprises a second shell, a second micro-perforated plate arranged above the second shell and a second Helmholtz resonant cavity arranged below the first shell; the third sound absorption assembly comprises a third shell, a third micro-perforated plate arranged above the second shell and a plurality of third Helmholtz resonant cavities arranged below the first shell; the first sound absorption assembly, the second sound absorption assembly and the third sound absorption assembly are distributed in parallel.

The present invention relates to a broadband sound absorption device using area division, the device comprising: Helmholtz resonators including a neck portion and a cavity portion connected to the neck portion and having a predetermined area and thickness; and a unit sound absorber including at least one pair of the Helmholtz resonators, wherein a plurality of unit absorbers are arranged on a plane or curved surface, and the plurality of sound unit absorbers are formed to have cavity portions with different areas to minimize the thickness while enabling sound absorption for a wider band.

------ Acoustic Enclosure and Method for Leveling an Acoustic Enclosure The present invention relates to an acoustic enclosure (20) comprising a loudspeaker (21) mounted flush on a front face of the enclosure (20), characterized in that at least one Helmholtz resonator (26) is formed on the front face of the enclosure (20) between each lateral edge of the front face and the loudspeaker (21), the at least one Helmholtz resonator (26) being dimensioned to have a band gap to block the propagation, in the plane of the front face of the enclosure (20), of acoustic waves in the useful frequency band of the loudspeaker (21). Figure to be published with the abstract: Figure 6a

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies selected via interchangeable portions. A sound absorbing unit cell is designed and constructed in two parts based on a desired resonance frequency, such as a neck portion and air chamber portion. The portions are dimensioned such that when coupled together, Helmholtz resonators are formed that resonate at a desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A portion with different dimensions can be interchanged to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The invention relates to the technical field of sound absorption, noise reduction and impact resistance, in particular to a multifunctional tunable bionic sound absorption and collision prevention integrated superstructure and a preparation method thereof.The multifunctional tunable bionic sound absorption and collision prevention integrated superstructure comprises a shell, an upper sound absorption layer, a lower sound absorption layer and a middle collision prevention layer, the sound absorption layer is provided with a plurality of curved-surface microwell plates which are connected end to end to form a cavity, and the embedded pipe is combined with the cavity to form a Helmholtz resonator; the anti-collision layer is composed of an energy absorption unit array. The preparation method comprises the steps that a three-dimensional model is firstly built, then a laser scanning mode and parameter printing are set, then heat treatment is conducted, then cutting and layer taking are conducted, and finally the superstructure is manufactured through glue joint. The sound absorption and noise reduction functions and the energy absorption and anti-collision functions are integrated, the sound absorption performance is improved through the bionic structure, energy is efficiently absorbed through the middle layer dot matrix, adjustable performance and lightweight design are achieved through parameterized design, the additive manufacturing process is simple, convenient and efficient, and large-scale production and application are facilitated.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via MEMS actuators. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A bimorph MEMS actuator and / or moveable part in the resonators, controlled by a controller, facilitates changing of the airflow the unit cells to adjust the resonant frequencies thereof, to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via a shared tuning element, e.g., a screw, or a piezoelectric actuator. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Collectively moveable floors in the resonators facilitate changing the resonators' air cavity dimensions, to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The invention discloses a perforated plate structure based on Helmholtz and acoustic black holes, which comprises a perforated plate and a bottom rigid wall which are distributed in parallel, and the perforated plate, the bottom rigid wall and an outer side rigid wall are closed to form a resonant cavity; the bottom rigid wall is provided with a plurality of partition plates distributed in a latticed mode, the resonant cavity is divided into a plurality of sub resonant cavities, the perforated plate is provided with a plurality of acoustic black hole structures, and one acoustic black hole structure is arranged in each sub resonant cavity. A round hole is formed in the perforated plate at the central position of the acoustic black hole structure, and the round hole is used as a neck part of the Helmholtz resonance structure; a gap neck exists between the partition plate and the perforated plate, and an acoustic black hole molded line II is arranged on the partition plate. The perforated plate structure can increase the absorption efficiency of sound waves with specific frequency, dissipation is carried out through the damping sound absorption material, an energy absorption-energy consumption trap is formed, the vibration and noise reduction effect is achieved, and meanwhile the sound waves entering the resonant cavity are dissipated again through the gap type Helmholtz resonance structure between the partition plate and the perforated plate.

The invention relates to a parallel Helmholtz resonant cavity with adjustable sound absorption performance, and the resonant cavity comprises a main body cavity which is internally provided with a plurality of sound absorption cavities in parallel, and the top surface of each sound absorption cavity is provided with a first sound absorption hole and a second sound absorption hole at an interval along a first direction; the upper cover plate is slidably connected with the main body cavity in the first direction, a plurality of communicating areas are arranged on the upper cover plate, and a plurality of third sound absorption holes and fourth sound absorption holes are formed in each communicating area at intervals in the first direction; the plurality of sound absorption cavities and the plurality of communication areas are arranged in a one-to-one correspondence manner; the PVC gel drivers are connected with the upper cover plate, the corresponding first sound absorption holes and the corresponding third sound absorption holes are overlapped and communicated when the PVC gel drivers are not powered on, and the PVC gel drivers contract when the PVC gel drivers are powered on so that the corresponding second sound absorption holes and the corresponding fourth sound absorption holes can be overlapped and communicated. Through the design of the parallel sound absorption cavities, low-frequency broadband sound absorption with multiple sound absorption peaks is generated, and further, the low-frequency broadband sound absorption effect aiming at different frequencies is achieved on the premise that the size parameters and the structures of the sound absorption cavities are not changed.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via actuators, e.g., piezoelectric motors. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Moveable partitions in the resonators, controlled by piezoelectric actuators, facilitates changing of the resonators' air cavity dimensions, to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The invention discloses a low-frequency sound absorption device for a wind tunnel corner flow deflector, and the device comprises a housing which is internally provided with a low-frequency sound absorber and an impedance matching layer. The low-frequency sound absorber comprises a Helmholtz resonance cavity, a sealing ring and an elastic support, the Helmholtz resonance cavity is distributed in the sealing ring in a square lattice or rectangular lattice mode, and the sealing ring is connected with the shell through the elastic support; the impedance matching layer comprises a porous material layer, an air matching layer and a gradual change section cavity, the porous material layer is connected with the surface, closest to sound wave incidence, of the shell, the air matching layer is located between the porous material layer and the gradual change section cavity, and the sectional area of the gradual change section cavity is gradually increased in the sound wave incidence direction. The thickness of the low-frequency sound absorption device does not exceed 650 mm, the low-frequency sound absorption device is high in aerodynamic noise absorption coefficient at the low frequency band of 50-200 Hz, has excellent high-temperature resistance, can stably operate in the working environment of 150 DEG C or above, and meets the strict working conditions of a wind tunnel laboratory.

The invention belongs to the technical field of fluid mechanical control, and particularly relates to an integrated water pump energy-saving control system which comprises a heterogeneous sensing array, an intelligent optimization controller, a dual-mode energy recovery device, a multi-scale feature analysis module and a cloud platform diagnosis system. The heterogeneous sensing array comprises pressure gradient sensors, multi-frequency voiceprint sensors and an electromagnetic-ultrasonic composite flowmeter, the pressure gradient sensors are arranged at 0.5 D intervals in the axial direction of the pipeline, the voiceprint sensors are provided with Helmholtz resonant cavities, and the composite flowmeter automatically switches electromagnetic / ultrasonic measurement modes according to Reynolds numbers. A dual-mode energy recovery device is adopted, control optimization energy saving and energy recovery energy saving are achieved, the comprehensive energy saving amount reaches 33.7%, the flywheel-piezoelectric composite energy storage system achieves 82% of energy conversion efficiency, and compared with a traditional single mode, the energy conversion efficiency is improved by 19.6%.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via MEMS actuators. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A moveable partition in the resonators, controlled by MEMS actuators, facilitates changing of the resonators' air cavity dimensions, to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The invention discloses a bionic high-bearing-capacity Helmholtz resonator, belongs to the field of engineering bionics and acoustic superstructures, and aims to solve the technical problem that a traditional sound absorption material and excellent mechanical properties are difficult to integrate. The resonator comprises a plurality of top plates, a plurality of bionic Helmholtz resonator arrays and a bottom plate, one top plate is positioned above one bionic Helmholtz resonator array to form a group of bionic Helmholtz resonator array units, the plurality of bionic Helmholtz resonator array units are arranged from top to bottom, and the lowest bionic Helmholtz resonator array unit is arranged on the bottom plate. On the premise of perfecting the structural design of the sound absorption cavity and having a high sound absorption coefficient, the structure of the sound absorption unit is remodeled, the overall toughness and strength of the sound absorption device are remarkably improved, the service life of the sound absorption device is prolonged, and a novel application direction is developed. The overall sound absorption structure is light, thin and compact, the mechanical properties such as compression resistance and bending resistance are remarkably improved, and manufacturing and using are easy.

The invention discloses a multilayer Helmholtz resonator coupled with an acoustic black hole. The multilayer Helmholtz resonator comprises a shell, a Helmholtz resonator A and a Helmholtz resonator B. The Helmholtz resonator A and the Helmholtz resonator B are arranged in the shell. A double-layer Helmholtz resonator is used, and an acoustic black hole structure is coupled to the joint of a Helmholtz resonator A and a Helmholtz resonator B. Firstly, the acoustic black hole structure reduces the quality of the Helmholtz resonator A and ensures that the multilayer Helmholtz resonator is light and thin, and the opening A generated by cutting off the multilayer Helmholtz resonator also provides an access port for the neck tube B; moreover, due to the structural characteristics of the acoustic black hole structure, part of sound waves can be effectively prevented from being reflected any more, and certain sound absorption performance is improved. In addition, the acoustic black holes can absorb sound in a wide frequency domain, and the sound absorption frequency band of the Helmholtz cavity is expanded.

The invention provides a conical embedded tube type Helmholtz resonator structure parameter generation method and device, and belongs to the field of mechanical engineering, and the method comprises the steps: obtaining sound absorption coefficient curves of a plurality of sample conical embedded tubes with known structure parameters; training the constructed forward prediction network by taking the structural parameters as input and the sequence extracted from the corresponding sound absorption coefficient curve as a label to obtain a trained forward prediction network; the constructed reverse design network and the trained forward prediction network are connected in series, a sequence extracted by an acoustic absorption coefficient curve is used as an output label and an input of the series network at the same time, forward prediction network parameters are fixed, and reverse design network parameters are trained; wherein the output of the reverse design network is the input of the forward prediction network, and the trained reverse design network is used for generating structural parameters. According to the method, the design steps are simplified, the design time is shortened, meanwhile, the design complexity is reduced, and the accuracy of structural parameter design is improved.

The invention discloses an acoustic metamaterial sound absorption structure and a transformer substation equipment noise reduction device, and relates to the technical field of transformer substation noise reduction, the acoustic metamaterial sound absorption structure comprises two shells arranged in parallel and a honeycomb structure arranged in the two shells; the honeycomb structure comprises a plurality of cavity units, the cavity units are periodically and continuously arranged, an opening of each cavity unit faces one shell, a hole is formed in the position, corresponding to the opening of each cavity unit, of one shell, and a Helmholtz resonance cavity is formed by each cavity unit, the two shells and the holes. Low-frequency-band noise enters the Helmholtz resonance cavity through the holes and resonates with the inherent frequency of the cavity, potential energy of sound waves is converted into heat energy to be counteracted, therefore, propagation of the sound energy is weakened, the sound waves are continuously consumed in the propagation process, the noise is further absorbed, and the problem that an existing noise reduction device is poor in low-frequency noise reduction effect is solved.

The invention discloses a tunable MEMS (Micro Electro Mechanical System) structure based on a piezoelectric laminated structure, which comprises a substrate, the substrate is provided with a front surface and a back surface, the back surface of the substrate is provided with a back cavity, the back cavity provides a vibration space for a vibrating diaphragm, and a piezoelectric layer grows on the front surface of the substrate. A height plate is arranged on the front side of the substrate in a sealed mode, a dielectric cavity is formed by the internal space of the height plate and the substrate, the piezoelectric layer is located in the dielectric cavity, a through hole communicated with the dielectric cavity is formed in the side wall of the height plate, and a Helmholtz resonant cavity of the vibrating diaphragm is constructed by the dielectric cavity. According to the tunable MEMS structure based on the piezoelectric laminated structure, the height plate can form a Helmholtz resonant cavity of the vibrating diaphragm, the resonant frequency of the vibrating diaphragm is adjusted, and energy is efficiently coupled.

The present invention belongs to the field of noise control, and discloses a low-frequency broadband ventilation duct muffler based on a rough necked Helmholtz resonator. The low-frequency broadband ventilation duct muffler includes a cylindrical shell (1), a ventilation hole (2) and a sound absorption unit (3). A ventilation hole (2) is arranged at the center of the cylindrical shell (1), and the sound absorption unit (3) is uniformly arranged between the ventilation hole (2) and the cylindrical shell (1), and the sound absorption unit (3) is annular; the sound absorption unit (3) includes a rough neck (3-1) and a cavity (3-2), the bottom end of the rough neck (3-1) is connected to the top end of the cavity (3-2), and the cavity (3-2) is arranged at the lower end of the whole low-frequency broadband ventilation duct muffler. The present invention is used to solve the problems that the existing ventilation duct muffler has a relatively high sound absorption peak frequency, a single sound absorption peak, and a relatively low sound absorption coefficient in the low-frequency range.

The invention discloses a low-frequency broadband sound absorption metamaterial adaptive wing and a design method thereof, and belongs to the technical field of aircraft design. The problem that in the prior art, a traditional aircraft wing and a design method thereof are difficult to achieve the low-frequency and broadband noise reduction effect is solved. The wing comprises a leading edge inner side slat, a leading edge outer side slat, a main wing, a trailing edge inner side flap and a trailing edge outer side flap, the leading edge inner side slat and the leading edge outer side slat are connected with the front side of the main wing, and the trailing edge inner side flap and the trailing edge outer side flap are connected with the rear side of the main wing; the metamaterial sound absorption strips are embedded into concave cavities of the leading edge inner side slat and the leading edge outer side slat respectively, the metamaterial sound absorption strips are embedded into the leading edge of the main wing, each metamaterial sound absorption strip is composed of a Helmholtz resonator array composed of single-layer Helmholtz resonator units, and each metamaterial sound absorption strip is provided with a micro-perforated surface with continuous curvature. The noise reduction level of the wing is effectively improved, the sound absorption frequency band is wider, and the method can be applied to sound absorption wing design.

The invention relates to the technical field of acoustic metamaterial structures, in particular to a high-bearing coupling stepped Helmholtz cavity honeycomb sound absorption structure which comprises a plurality of honeycomb structures arranged periodically. A top micro-perforated hole is formed in the center of the top surface of the honeycomb structure, a vertical sound channel is formed in the center of the interior of the honeycomb structure, and a plurality of Helmholtz resonant cavities are formed in the periphery of the interior of the honeycomb structure; the vertical sound channel is communicated with the micro-perforated structure, and the heights of the Helmholtz resonant cavities are distributed according to an arithmetic progression; and the vertical sound channel is communicated with the Helmholtz resonant cavity through a resonant cavity micro-perforated hole. Through collaborative innovation of acoustic topological optimization and mechanical bearing design, the technical paradox that low frequency needs a thick layer and light weight is difficult to bear load of a traditional sound absorption material is broken through, and an innovative solution is provided for cabin acoustic design of aerospace, high-speed rails and other high-end equipment.

The invention discloses a neck embedded ring type Helmholtz resonator, which relates to the technical field of low-frequency sound absorption structures and comprises a resonator main body, an embedded neck and a porous material lining. The resonator main body comprises an outer wall surface and a closed cavity; the embedded neck part penetrates through the top wall surface of the main body and comprises a neck part wall surface and an internal periodic convex ring structure; the porous material lining is attached to the inner wall of the closed cavity, and a first gap is formed between the porous material lining and the wall face of the neck. According to the resonator, the sound energy dissipation capacity and parameter harmonility are improved through the neck circular ring, the low-frequency sound absorption capacity is enhanced through the porous material in the cavity, the sound absorption peak value and frequency can be regulated and controlled by adjusting the parameters of the neck and the circular ring and selecting the type of the porous material, and the resonator is simple in structure, wide in application and beneficial to production.

The invention relates to the technical field of sound absorption and noise reduction, in particular to an anti-impact sound absorption and noise reduction lattice superstructure which comprises an array formed by connecting a plurality of sound absorption cavities, each sound absorption cavity is a truncated octahedron formed by a plurality of panels, and the panels comprise eight regular hexagonal panels and six quadrilateral panels. The two adjacent edges of every two adjacent panels are connected through a hollow truss, and a micro hole is formed in the center of each panel. According to the adjustable Helmholtz resonator, the hollow structure is introduced, stress concentration at truss nodes is effectively reduced, the panels are arranged between the adjacent trusses, an internal air phase is constructed through the micropore design, the sound absorption frequency band of the structure is widened, the sound impedance of the structure can be adjusted through the micropores, and therefore the multiple complete adjustable Helmholtz resonators are formed; when the frequency of incident sound waves is close to the inherent frequency of the resonator, the air columns in the micropores generate strong vibration, sound energy is consumed due to the thermal viscosity effect, and the sound absorption and noise reduction structure can have good sound absorption and energy absorption effects while having good mechanical performance.

The invention relates to the technical field of vehicle air duct noise reduction, in particular to a noise reduction pipeline, a vehicle air conditioner noise reduction air duct and a vehicle. The noise reduction pipeline comprises a first noise reduction pipe section, the first noise reduction pipe section comprises a plurality of noise reduction units, each noise reduction unit is provided with a Helmholtz resonant cavity, and the Helmholtz resonant cavities communicate with the circulation space of the first noise reduction pipe section. By designing the noise reduction units with the Helmholtz resonant cavities, the noise reduction frequency of each noise reduction unit can be designed within a certain range, so that the noise reduction frequency band of the first noise reduction pipe section can be adjusted within a certain range, and broadband noise reduction is achieved.