382results about How to "Reduce aerodynamic noise" patented technology

Flap side edge noise mechanisms have been addressed in a large number of studies during the last decades. A specific vortex system emanates from the flap side edge due to the static pressure difference between the upper and lower flap surfaces. Such pressure difference leads to a merging between the two vortex systems that are generated on the upper and lower edges of the flap side contour. The present invention intends to show the application of a perforated blade seal (21) at the lower (11) and/or upper (8) side edges of the control surface contour, such as a flap (3), with the purpose of acting as a vortex generator, making difficult for the lower vortex system to move upwards and merge with the upper vortex system. The perforated blade seals (21) are preferably arranged on the inboard and outboard edges of high lift flaps (3).

The invention discloses a range hood centrifugal fan with a double air inlet structure. The range hood centrifugal fan comprises a volute and an impeller arranged in the volute, the volute comprises a front cover plate, a rear cover plate, an annular middle shell and volute tongues, the annular middle shell is connected between the front cover plate and the rear cover plate, a motor is arranged at the center of the impeller, each volute tongue is provided with a volute tongue surface projecting along a direction far away from the joint of the volute tongue and the shell, each volute tongue surface comprises a front inclined curved surface and a rear inclined curved surface which are asymmetric and are in smooth transition connection, and the intersecting line of the two inclined curved surfaces is the outermost projection of the volute tongue surface. By the aid of the bidirectionally inclined volute tongues, distribution of the inclined curved surfaces conforms to airflow velocity distribution, a new noise source generated at the volute tongue more effectively offsets part of original noise, and noise reduction capacity is improved. The intersecting line of the two inclined curved surfaces of each bidirectionally inclined volute tongue is aligned to a central disk of the impeller as far as possible, the inclined directions of the volute tongues corresponding to air inlets in two sides of the double air inlet impeller are consistent, and better noise reduction effects are achieved.

The invention discloses a centrifugal fan impeller, which comprises a front ring and a back ring, wherein a plurality of blades are fixedly arranged between the front ring and the back ring. The centrifugal fan impeller is characterized in that the outlet ends of the blades form a wave-shaped sawtooth type by a plurality of sawteeth. The outlet ends (tail edges) of the blades are provided with structures in the wave-shaped sawtooth type, and the wake vortex shedding positions of the tail edges of the blades are changed, so the distance between the vortex centers is increased, the disturbance of the shedding vortex on the wake flowing is inhabited, and the pneumatic noise caused by the wake vortex and the unsteady pressure fluctuation of the blade surfaces is further reduced. The height and the width of the sawteeth are limited, the noise is further reduced, and the influence of the sawteeth on the pressure and air quantity reduction of a fan can also be reduced.

PROBLEM TO BE SOLVED: To provide an outdoor device for an air conditioner increasing the air capacity and reducing the noise by improving the structure of a bellmouth guiding the air delivered from a ventilation fan. SOLUTION: This outdoor device is provided with a housing formed with a suction port and a delivery port, a heat exchanger and the ventilation fan provided inside the housing, and the bellmouth provided in the delivery port and disposed in the outer circumference of the ventilation fan. The bellmouth has its inlet part having a fixed curvature and formed of a curved part enlarged inward the delivery port, and its outlet part making a prescribed angle and formed of a straight slope part enlarged outward the delivery port, and a horizontal straight line part is formed between the curved part and the straight slope part. The bellmouth is so formed that the ratio of the lengths of the curved part, the horizontal straight line part, and the straight slope part becomes approximately 7:1:2, the curvature radius of the curved part becomes approximately 20-35 mm, and the inclination angle of the straight slope part becomes approximately 40 deg.-50 deg..

The invention discloses a pressure expander of a centrifugal compressor. The structure of the pressure expander is improved, and high application value is achieved for further improving working performance of the pressure expander. A short blade is arranged in runners of every two adjacent long blades; the front edges of the long blades are curved surfaces and are arranged obliquely, and the included angles between front edge lines and the central axis of a wheel disc are 6 degrees to 8 degrees; the radius of curvature of the front edges of the long blades is gradually increased from the wheel disc to a wheel cover; each long blade is provided with three broken-line-shaped channels penetrating through a corresponding pressure surface and a corresponding suction surface; tail edge wing tips are arranged on the portions, located on the pressure surfaces, of the rear edges of the long blades. Occurrence of separation of airflow on the surfaces of the blades is restrained through the short blades in the runners of the adjacent long blades; the pressure differences between the pressure surfaces and the suction surfaces are reduced through the broken-line-shaped channels, the adverse pressure gradient is reduced, and separate airflow on boundary layers of the suction surfaces at the tails of part of the blades is effectively blown away; increase of wing tip vortexes generated by the pressure differences between the suction surfaces and the pressure surfaces on the rear edges of traditional wing-type blades can be restrained through parabola-shaped winglets on the tail edges.

The invention relates to the technical field of ventilators, in particular to a ventilator integral impeller and method for preparation. An impeller angle is not accurate, which is caused by the affect of many reasons which are machining error, blade installation angle measurement error, electric welding thermal deformation error and worker processing technical level and the like, thereby the intensity of a ventilator fan is reduced, the noise is increased, the work efficiency is low, the power consumption is large and the maintenance ratio is high. In order to overcome the above defects, the invention uses the technical scheme that the ventilator integral impeller comprises a blade, a hub, a spoke and a bearing sleeve, wherein the blade, the hub, the spoke and the bearing sleeve are a whole body which are connected together through casting in one time. The ventilator integral impeller is made through casting in one time, the problems which are common in processing of the impellers such as rosin joint and unclosed riveting and the like do not exist, the intensity is high, the security is excellent, the production cost is low, the energy consumption is saved, the environmental condition is improved, and the economic benefit is increased.

A railway vehicle brake disc which can reduce aerodynamic sound raised high speed running, improve cooling performance during braking, and improve durability comprises a donut-shaped disc section having a sliding surface on a front surface side, a plurality of fin sections, each convexly provided in a rear surface of the disc section in a radial pattern, and a bolt hole passing through the disc section and the fin section. The disc section is mounted on a wheel in a state where the fin sections contact a plate section of the wheel using a bolt inserted into the bolt hole. The fin section has a groove formed along a circumferential direction in at least one of an area on an inner peripheral side and an area on an outer peripheral side of the bolt hole when viewed in a radial direction of the disc section.

A wind turbine blade having a noise reducing device attached at its trailing edge including serrations, whereby the serrations and the trailing edge include an angle between 75° and 90° is provided. The wind turbine blade may be provided wherein the angle is between 80° and 90°. In an embodiment, the wind turbine blade may be provided wherein a serration has a rounded shape at its tip and/or its notch. A wind turbine including a tower, an electrical generator with a rotor shaft and a hub to which wind turbine blades are connected, wherein the wind turbine includes wind turbine blades.

The invention discloses a range hood and a volute thereof. The range hood includes: a casing provided with a first external air exit and a second external air exit; a volute disposed in the casing, with the volute body comprising a base plate, a top plate, and a side wall plate arranged between the base plate and the top plate and being equipped with an external air outlet communicated with the first external air exit and a second external air exit; a wind wheel disposed in the casing body, with the opening direction of the external air outlet being orthogonal to the opening direction of the second external air exit; and an external switching cover plate, which is movably disposed on the volute or casing between a first position where the first external air exit is opened and the second external air exit is closed and a second position where the first external air exit is closed and the second external air exit is opened, wherein the angle alpha between the external switching cover plate at the second position and the opening direction of the second external air exit is greater than 0 and smaller than 90 degrees. According to the embodiment of the invention, the range hood has the advantages of small air volume and wind pressure loss, high wind wheel efficiency, and low pneumatic noise, etc.

The invention discloses an axial-flow swept blade. The surface of the axial-flow swept blade comprises a suction curved surface, a pressure curved surface, an upper curved surface and a lower curved surface, wherein the upper curved surface and the lower curved surface are covered with side surfaces of two cylinders, and the radii of the cylinders corresponding to the upper curved surface and the lower curved surface are recorded as R2 and R1 respectively, and R2 is larger than R1; the side surfaces of a series of coaxial cylinders formed by changing the radius r from R1 to R2 intersect with the axial-flow blade to form a series of intersection planes, the series of the intersection planes are spread along the plane, a series of spread sections are obtained, and a spatial stacking line of the blade is obtained accordingly; the projection line of the spatial stacking line in a YOZ plane is a cubic spline curve with the change of the height ratio. The problems of lower efficiency and large noise of an axial-flow fan can be effectively solved by means of improvement of key shape parameters.

The invention discloses a noise-reducing method for an electric fan based on blade modification and an improved blade structure of the electric fan. The method comprises the following steps of: (1) establishing a hydromechanic calculating model of an original blade structure of the electric fan; (2) performing kinetic analysis on the original blade structure of the electric fan to obtain fluid field data and monitoring the sound pressure level of noise of a preset measuring point, wherein the fluid field data comprises a blade surrounding vorticity value and vortex structure distribution; (3) performing a modified design on the fan blade structure of the electric fan continuously and performing kinetic analysis on the modified blade structure of the electric fan to obtain fluid field data and measured point noise data, and reducing the blade surrounding vorticity value and crushing large vortexes into small vortexes till the sound pressure level of noise of the preset measuring point is reduced on the premise that the blast capacity is invariable at same input power; and (4) manufacturing a fan model, measuring the blast capacity and the sound pressure level through experiments, and verifying the reducing effect of the sound pressure level of the noise of the measured point. By modified noise reduction on the blade of the fan by means of computational fluid mechanics, the method is high in pertinence and high in operability.

The invention relates to an eddy generator for a wind turbine blade. The eddy generator comprises multiple fins, and each fin is a triangular plate part with a circular corner as a top corner. According to the eddy generator, stalling can be effectively delayed, the pneumatic performance of the blade is improved, the situation can be reduced that the power generation loss of a wind turbine is caused by blade surface pollution, and the eddy generator can be applied to power increase transformation of the wind turbine blade which is operated. The invention further relates to a method for determining the mounting position of the eddy generator on the wind turbine blade and a method for installing the eddy generator on the wind turbine blade. According to the methods, the mounting and positioning process is precise and reliable, and the mounting efficiency is high.

The invention discloses a combined jet-flow control device for a helicopter rotor blade and a control method of the combined jet-flow control device. The combined jet-flow control device comprises a plurality of blades with a geometric shape of NACA0012-CFJ airfoil shape, each blade is provided with a combined jet flow device, the combined jet flow devices are continuously distributed along the unfolding direction of the blade, each combined jet flow device comprises a high pressure air chamber and a low pressure air chamber, the high pressure air chamber is communicated with an air blowing opening at the front edge, the low pressure air chamber is communicated with an air suction opening at the rear edge, and the high pressure air chamber and the low pressure air chamber are communicated with an air pump device inside a helicopter by virtue of an airflow pipeline. A novel-concept initiative flow control technique of combined jet flow is innovatively adopted to suppress the dynamic stalling of the rotor blade, the air is blown from the opening adjacent to the front edge of the upper surface of the airfoil to the rear edge, the air is sucked through the opening adjacent to the rear edge, and the air suction volume and the air blowing volume are ensured to be the same, so that the recycling of the air is realized, and the control method is flexible.

The invention discloses a whole vehicle thermal management system of a pure electric vehicle and a management method. A heat pump type air conditioner system, a battery pack thermal management systemand an electronic control cooling system are arranged on the pure electric vehicle. The system comprises a heat pump type air conditioner refrigerant liquid circulating loop, a coolant liquid circulating loop of the battery pack thermal management system and the electronic control cooling system, and an ECU control center. The two liquid circulating loops are coupled on a first evaporator and a second evaporator, two liquid inlet and outlet internal pipelines of the first evaporator and the second evaporator are independent, and liquid flow directions are designed in a convection mode. Heat among the three sub-systems can be utilized under the condition of guaranteeing driving and riding comfort, an external cold source and sub-system heat sources are fully utilized, and the energy consumption of the whole vehicle thermal management system is reduced.

The invention discloses a novel multi-blade centrifugal fan. The novel multi-blade centrifugal fan comprises a volute, a volute tongue and a plurality of fan blades fixed in the volute, wherein one lateral side of the volute tongue is fixed on the inner lateral side of the air outlet of the volute, the other lateral side of the volute tongue is a concave face, a plurality of air guide grooves are formed in the concave face, the two end faces of each fan blade are arc-shaped faces, a zigzag structure is arranged on one arc-shaped face of each fan blade, a bionic non-smooth structure is arranged on the other arc-shaped face of each fan blade, and airflow sequentially passes the bionic non-smooth structures and the zigzag structures and then is discharged from the air outlet of the volute. The novel multi-blade centrifugal fan has the advantages that the air quantity and air pressure of the fan are increased effectively, the noise of the fan is lowered effectively, and the efficiency of the fan is increased effectively.

The invention discloses a method for predicting the acoustic radiation rule value of the noise of a wind turbine. The method comprises the steps of establishing a wind turbine model, defining flow field grids, calculating a flow field based on large eddy simulation and calculating sound field distribution based on the indirect boundary element method. The method is used for predicting the acoustic radiation rule value of the noise of the wind turbine by means of flow field calculation data combined with the boundary element method, with the assistance of software, the calculating processes can be simplified greatly, the prediction process is made simple, the calculating result is accurate, the calculated amount is small, speed is high, and the method has great application value in engineering.

The invention specifically relates to a wheel rim-driven shaftless fan. The wheel rim-driven shaftless fan comprises a stator component, a rotor component and a lubrication device, wherein the stator component comprises a front end cover 4, an inlet-side slide bearing 5, an air barrel 3, an armature 10, an outlet-side slide bearing 14 and a rear end cover 13, wherein the rotor component comprises an inlet-side shaft neck 6, a wheel hub 16, permanent magnets 9, blades 8 and an outlet-side shaft neck 15, the inlet-side shaft neck 6 and the outlet-side shaft neck 15 are both L-shaped and both installed on the wheel hub 16 in a manner of interference fit, a plurality of grooves are uniformly formed in the excircle surface of the wheel hub 16, and the permanent magnets 9 are inlaid in the grooves in the excircle surface of the wheel hub 16; a blade handle is arranged at the blade tip of each blade 8, each blade handle is an incurved tile, and all the tiles are spliced to just form the inner diameter of the wheel hub; and the lubrication device comprises an oil cup 12, a guide pipe 2 and an adjustment valve 1, one end of the guide pipe 2 is connected to the oil cup 12, and two outlets are formed in the other end of the guide pipe 2. According to the wheel rim-driven shaftless fan disclosed by the invention, a wheel hub needed for driving the central shaft of a traditional fan is avoided, the separation of secondary flow and a boundary layer at each blade root is reduced, and the flowing condition at each blade root is improved, so that the efficiency of the fan is increased; and moreover, a blade tip gap at each blade tip is avoided, so that detouring flow at each blade tip is avoided, a flow field structure is improved, energy conversion efficiency is increased, and a pneumatic noise is lowered.