498 results about "Helmholtz resonator" patented technology

The present invention is a system and method to significantly reduce noise associated with air-moving devices such as an axial flow fan using a fan shroud and barrel combination with built in silencers such as Helmholtz resonators. The invention can be applied to a variety of applications such as a thermal management system for a fuel cell powered vehicle. The resonator can be a hollow cavity in networks attached to an outer or inner barrel or shroud and tuned to reduce noise at predetermined noise frequency ranges within the airflow. The invention can also attach stator members on the inner surface of the outer barrel to further reduce noise. Additional sound absorbing material, such as steel wool, can be disposed within the resonator cavity.

An acoustic resonance device is installed in a compartment of a vehicle so as to reduce a low-frequency sound pressure (or noise) dependent upon a natural vibration. Specifically, an acoustic resonance device is a panel/diaphragm resonator, a resonance pipe, or a Helmholtz resonator, the inner space of which communicates with the compartment via an opening. The acoustic resonance device is positioned in proximity to an antinode of sound pressure owing to a natural vibration occurring in a driver/passenger space inside the compartment. Alternatively, the acoustic resonance device increases a particle velocity at a specific natural frequency or decreases sound pressure at an excitation frequency which occurs due to an external condition of the vehicle. The acoustic resonance device can be installed in a roof, a seat, a pillar supporting the roof, or a door of a vehicle.

A bleed air duct that preferably includes an inlet section configured to include a flush scoop and a louver. The louver is located and configured such that in the desired operating flow range of the duct, the fluid entering the flush scoop is disturbed and as a result creates a low pressure region downstream of the louver. The low pressure region substantially eliminates the generation of any pressure pulses and acoustic resonance also known as Helmholtz resonance.

Under certain conditions, the fuel delivery system can contribute to the formation of strong dynamic pressures in the combustor of a turbine engine. Embodiments of the invention provide a system for dynamically stiffening the fuel supply passage to suppress damaging combustion dynamics. To that end, a Helmholtz resonator can be placed along and in branched relation to the fuel supply passage. The resonator can produce the effect of adding a pressure release opening at a selected location in the fuel line, causing a shift in the fuel line pressure wave pattern that blocks fuel flow fluctuations at the outlet of the fuel passage at the frequency of the oscillation. The pressure wave shift results in a shifting of the volume velocity wave pattern. Ideally, the resonator can be positioned along the flow path such that the volume velocity of the fuel at the fuel passage exit is minimized.

The invention relates to a multiple helmholtz resonator parallel cellular sandwich wood sound absorption plate, belonging to the field of sound absorption technologies. The invention solves the problems of small chamber volume ratio, narrow sound absorption frequency band and poor sound absorption effect in the traditional sound absorption panels. Technical essential is characterized in that a sandwich layer is a cellular sandwich layer; the cellular sandwich layer is formed from splicing a plurality of cylinder bodies with hexagonal cross sections; an inner cavity of each hexagonal cylinder body is a cell cavity chamber; the chamber volume ratio of the sandwich layer is larger than 90%; the area of perforation shape surrounded by contour lines of each perforation is less than a half of the hexagonal area of corresponding sandwich layer; and each small through hole on a panel is communicated with the cell cavity chamber at the corresponding position of the sandwich layer. The invention has wider sound absorption frequency band and better medium high frequency sound absorption performance, and the sanding wave tube method sound absorption coefficients respectively reach 0.8, 0.9 and 0.7 at 500Hz, 1000Hz and 2000Hz. In addition, the invention also has the characteristics of light weight, high ratio of strength to weight, good decorative effect, and the like; and wood resources can be saved, preparation process is simple, and cost is low.

An in-line resonator for an air induction system of an internal combustion engine is provided. The system includes a resonator housing, an upstream duct, a downstream duct, a conduit, a partition, and a sleeve. The conduit extends through the resonator housing connecting the upstream duct and the downstream duct. The partition is moveable within the resonator housing and divides the housing into an upstream chamber and a downstream chamber. The downstream chamber, the conduit, and the downstream sleeve cooperate to form a first Helmholtz resonator that is in fluid communication with the downstream duct. The upstream chamber, the conduit, and the upstream sleeve cooperate to form a second Helmholtz resonator that is in fluid communication with the upstream duct. Further, a means is provided to axially move the partition to vary the volume of the chambers concurrently with the length and/or area of the passages.

A gas turbine combustor having a Helmholtz resonator in a post-swirler homogenization zone upstream of the combustor zone. Embodiments of the present invention provide Helmholtz resonators that include cavities that occupy a remainder of a post-swirler homogenization zone, which also includes at least one flow-directing structure that passes a fuel/oxidizer mixture from a main swirler assembly into a combustion zone of a combustor. Thus, an open annular region of the combustor is converted into a multi-purpose zone that includes at least one Helmholtz resonator.

A piezoelectric microblower includes a vibrating plate including a piezoelectric element and arranged to be driven in a bending mode by applying a voltage of a predetermined frequency to the piezoelectric element, and a blower body arranged to fix both ends or a periphery of the vibrating plate and to define a blower chamber between the blower body and the vibrating plate, an opening being provided in a portion of the blower body facing a central portion of the vibrating plate. In a portion of the blower chamber corresponding to the central portion of the vibrating plate, a partition is provided around the opening and a resonance space is defined inside of the partition. A size of the resonance space is set such that a driving frequency of the vibrating plate and a Helmholtz resonance frequency of the resonance space correspond to each other.

An acoustic energy source for imparting acoustic energy into the Earth's subsurface includes an electrically driven transducer coupled to a source of swept frequency alternating current. A tunable Helmholtz resonator is disposed proximate the transducer. In one example, the resonator has a tuning device configured to maintain a resonant frequency substantially equal to an instantaneous frequency of the alternating current. The tuning device includes an actuator coupled to a sleeve, wherein the sleeve is disposed over selected numbers of openings in a wall of a tube on the resonator. The transducer and the resonator are disposed in a wellbore drilled through rock formations. The wellbore has a plurality of layers of fluid therein, each layer thereof having a different density and/or viscosity.

The tunable resonator is coupled to the engine speed control such that the resonator is set to a different frequency range when the engine speed is changed. The frequency range is changed by opening and closing necks and/or changing the effective volume of the resonator.

A supercharger has an inner wall defining an inner cavity for receiving lobed rotors for rotation therein, a low-pressure inlet and a high-pressure outlet. A sound attenuator is associated with the housing and located adjacent to the high-pressure outlet. The sound attenuator has a tuner chamber and circumferentially spaced tuner ports fluidly connecting the tuner chamber with the internal cavity of the housing to define a Helmholtz resonator. A land is defined between the circumferentially spaced tuner ports such that the high-pressure outlet and low-pressure inner chambers defined between the rotor lobes and the inner wall are fluidly connected when the rotor lobes are in alignment with the land to reduce the pressure differential between the high-pressure outlet and the low-pressure inner chambers.

An electronic apparatus includes a drive for recording/reproducing a recording medium, and a sound absorbing member having a Helmholtz resonator for insulating sounds at a predetermined frequency among sounds generated by the drive.

The invention provides a noise power-generating device and noise power-generating equipment consisting of the same. The noise power-generating device comprises a sound wave collecting pipe, wherein one end of the sound wave collecting pipe is opened; an air-isolating and sound-transmitting thin film is sealed at the opening of the sound wave collecting pipe; a trumpet-shaped inlet is also formed at the opening of the sound wave collecting pipe; a sound-isolating plate is arranged outside the sound wave collecting pipe 4; one end of the sound-isolating plate is connected with the trumpet-shaped inlet 1; the other end of the sound-isolating plate is connected with the closed end of the sound wave collecting pipe 4; the sound-isolating plate and the outer wall of the side surface of the sound wave collecting pipe form a cavity; a plurality of columns of acoustical-electrical converting units which are uniformly arranged along the axial direction are arranged on the side surface of the sound wave collecting pipe; each of the acoustical-electrical converting unit comprises a helmholtz resonator with a resonating cavity and an acoustical-electrical converter connected with the helmholtz resonator; the acoustical-electrical converter comprises a vibrating film arranged in the cavity in the tail end of the resonating cavity and connected with a coil through a connecting rod; a coil is sleeved on a magnetic pole; and the magnetic pole is arranged on the sound-isolating plate. The coil is connected with an output bus through a current-collecting wire, so that the mechanical energy of noise is converted into electric energy.

The invention relates to heat exchanger tubes acting like resonant tubes of a Helmholtz resonator and used as swirl tubes. They are capable of drastically increasing heat transfer in the boundary layers determining the heat flow to be exchanged as a result of their geometrically deformed surfaces.

A resonator is provided, having an adaptable resonator frequency for absorbing sound generated by a gas stream of a gas turbine. The resonator includes a neck section, a chamber and a deformable element being deformable under influence of a change of a gas turbine temperature of the gas stream. The shape of the deformable element is predetermined with respect to a respective gas turbine temperature. The neck section and the chamber form a volume of the resonator. The neck section forms a passage coupling the volume with the gas turbine. The deformable element is thermally coupled to the gas turbine in such a way that the shape of the deformable element depends on the respective gas turbine temperature. The deformable element forms a spiral and is installed to the neck section in such a way that an effective diameter of the neck section depends on the gas turbine temperature.

A noise reduction system for a device having a noise generating subsystem includes a Helmholtz resonator and a controller. The Helmholtz resonator is disposed in fluid communication with the noise generating subsystem, and includes an active material responsive to a control signal that adjusts a dimensional characteristic of the Helmholtz resonator in such a manner as to affect a resonance characteristic of the Helmholtz resonator. The controller is responsive to an operational characteristic of either the device or the noise generating subsystem to produce the control signal. In response to the operational characteristic, the control signal serves to affect the resonance characteristic of the Helmholtz resonator in such a manner as to reduce a noise arising from the noise generating subsystem, or create a desirable sound quality alteration.