56results about How to "Reduce jet noise" patented technology

An exhaust nozzle assembly for a gas turbine engine, the assembly comprises a main axis, an inner nozzle, an outer nozzle, a translatable centre-body and an actuator for translating the centre-body between a forward position and a rearward position. The centre-body is disposed radially inwardly of the inner nozzle thereby partly defining an inner duct for a core engine gas flow, an outer duct for a bypass gas flow is defined by the inner nozzle and the outer nozzle. The outer nozzle extends downstream of the inner nozzle and with the centre-body defines a final mixing duct having a final exhaust exit area. When the centre-body is in the forward position the final exhaust exit area is at a maximum area, and when the centre-body is in a rearward position the final exhaust exit area is at a minimum area.

In a supersonic aircraft, turbojet engine nacelles each containing two remote fans in the front half of the nacelle, for noise reduction at takeoff. During supersonic flight, a front wedge at the nacelle nose achieves external compression of intake air. The wedge is vertical, sending the airflow left and right inside the nacelle along its side walls. The two flows follow mirror image curved paths on their way to a turbojet, leaving unused space between them to house the fans in tandem. For takeoff, clutches connected to the turbojets's compressors are engaged. Driveshafts turn pinions against a gear on the same shaft as the remote fans. The fan output is discharged backward under the nacelle to produce thrust. The energy to turn the fans is taken from the turbojet cycle. The reduced exhaust jet velocity decreases its noise. Supercharging produces the extra power to turn the remote fans if multistage.

A plurality of hatches are distributed on the rear periphery of an engine cowl. The hatches are opened only when turbojet engine power is greater than cruising power. In an open position, the hatches draw hot air jets passing through an intermediate chamber before ejecting the jets through longitudinally-distributed communication components.

The invention discloses a water pipe flow stabilizing broadband muffler which comprises a water delivery pipe and a muffler casing. An expanded perforated pipe is fixedly installed on the inner side of one end of a muffler casing body fixedly connected with the water delivery pipe. An end plate is fixedly arranged at the other end of the muffler casing. A shunting perforated pipe is further fixedly connected onto the end plate, and a throttle ring is fixedly arranged at the port position of the inner end of the shunting perforated pipe. The inner diameter of the expanded perforated pipe is larger than the outer diameter of the shunting perforated pipe, the inner end of the expanded perforated pipe and the inner end of the shunting perforated pipe are in fixedly sleeved connection in a gapped mode, and the flowing cross area of the water delivery pipe is smaller than the sum of the hole flowing cross area of the end plate and the flowing cross area of the shunting perforated pipe. The water pipe flow stabilizing broadband muffler can achieve broadband muffling of the water pipe, effectively stabilize a flow field at the outlet end of the water pipe, reduce the water spraying-flowing speed and pressure, accordingly reduce water pipe port noise effectively and achieve the effects of flow stabilizing and broadband muffling.

A device for reducing the jet noise of a turbomachine, the turbomachine having a longitudinal axis and a substantially cylindrical nozzle extending along the longitudinal axis of the turbomachine, having a downstream end for mixing the flows of gas inside and outside the nozzle, the device comprising a plurality of corrugations disposed to extend the downstream end of the nozzle, and a plurality of notches disposed between pairs of successive corrugations in the plurality of corrugations, and the plurality of corrugations and the plurality of notches are asymmetrical relative to at least one axis perpendicular to the longitudinal axis of the turbomachine so as to generate a dual counter-rotating effect between the gas flows.

The invention discloses a method for calculating the radiation noise generated by the pipe wall of a water-filling pipeline during the reverberation method. According to the method, firstly, the radiation noise and the jet noise, generated due to the vibration of the pipe wall of a water-filling pipeline, are measured based on the reverberation method. Secondly, only the jet noise of the water-filling pipeline is measured and obtained based on the reverberation method, so that the radiation noise of the underwater water-filling pipeline generated during the vibration process is obtained. The above method is simple in calculation and high in efficiency. The radiation noise and the jet noise, generated by the pipe wall of the water-filling pipeline in a single non-noise-elimination pool and measured based on the reverberation method, is subtracted by the jet noise of the water-filling pipeline measured based on the reverberation method. In this way, the radiation noise of the water-filling pipeline generated during the vibration process is obtained.

The invention relates to an annular cover for a turbomachine nozzle, the cover having a plurality of patterns extending a trailing edge of said cover and spaced apart circumferentially from one another, each pattern having an outline that is substantially triangular in shape, with a base formed by a portion of the trailing edge of the cover and a vertex spaced downstream from the base and connected thereto by two sides. For each pattern, the vertex presents an outline that is substantially curved; each side is connected to the trailing edge of the cover following an outline that is substantially curved having a radius of curvature that is greater than the radius of curvature of the outline of the vertex; and the outline of each of the sides includes at least one point of inflexion having a tangent that is substantially parallel to the base.

The invention relates to a cowl for a turbomachine nozzle, the cowl including a plurality of repetitive patterns disposed to extend a trailing edge of said cowl and spaced circumferentially apart from one another. Each pattern is in the form of a quadrilateral having a base that is formed by a portion of the trailing edge of the cowl and two vertices that are spaced downstream from the base and that are connected thereto via two sides, each side having the shape of a parabola. Each pattern is asymmetrical relative to a midplane of the pattern containing a longitudinal axis of said cowl, and it comprises a first portion inclined radially towards the inside of the cowl, and a second portion inclined radially towards the outside of the cowl.

The invention relates to a primary cowl for a turbofan comprising a primary body generating a primary stream to be ejected through a primary nozzle, and a secondary body generating a secondary stream to be ejected through a secondary nozzle, the primary cowl being shaped so as to be positioned downstream from the primary body and to define, on the inside of the turbofan, the path followed by the primary stream downstream from the primary nozzle and, on the outside, the path followed by the secondary stream downstream from the secondary nozzle. The primary cowl comprises a coupling to a system for supplying a pressurized gas and at least one perforation for injecting the pressurized gas, through the perforation, into the secondary stream. The primary cowl preferably comprises a ring which has perforations and which is rotated about the axis of rotation of the turbofan.

According to the invention, a plurality of embossments (20) having a rectangular section is provided at the inner periphery of the outlet opening (7) of the fan duct (12), said embossments being separated by longitudinal channels (21) having a convergent (22C) and a divergent (22D) for the cold flow (9).