41results about How to "Reduce noise reduction costs" patented technology

The invention discloses a method for identifying a noise source in a waste heat boiler. The method comprises the steps that S1, a two-dimensional bare pipe model is established, the flow field and the sound field of bare pipes of two pipe arrays of a high-pressure superheater and a deoxidizing evaporator are respectively calculated in a simulated mode, the sectional characteristic frequency is calculated, and the characteristic frequency range inside the whole boiler is estimated; S2, a finned pipe finite element model is established, the flow field and the sound field of each single finned pipe in the two pipe arrays of the high-pressure superheater and the deoxidizing evaporator are respectively calculated in a simulated mode, the sectional characteristic frequency is calculated, and the characteristic frequency range inside the whole boiler is estimated; S3, the characteristic frequency of the pipe arrays is corrected; S4, the normal frequency is calculated and whether the normal frequency is excited to generate sound cavity resonance or not is judged; S5, sound transmission loss and sound insulation calculation are conducted on the boiler and total noise in the boiler is obtained with the combination of actually-measured noise data; S6, the contribution to the noise in the boiler by different kinds of noise is calculated, and a main source of the noise in the boiler is determined. The method can be used for accurately identifying the source of the noise inside the waste heat boiler of a gas turbine.

The invention discloses an array type muffer, the technical problems to be solved are to advance the silencing ability. The array type muffer is provided with an absorbing body in the tube, wherein the absorbing body is a tube provided with sound absorption material inside, the axis of the tube is arranged along the airflow direction in parallel, and the tube is fixedly arranged in the air pipe through the bracket. Compared with the existing technology, in the same length of the muffer, the absorption surface of the unit cross area is increased, the absorption property is advanced, the noise reduction effect is good, which ensures that in the same noise reduction effect, the length and the volume of the muffer are reduced, the air flow area of the unit cross area is increased, the flow velocity of the absorbing body is reduced, the air noise is reduced, the pressure loss is small, thereby reducing the pressure of the system fan, reducing the cost of the air system. The whole muffer isdecomposed into each small absorbing body and the parts for installing the bracket, which is convenient for the transportation and installment.

The invention discloses a central air conditioner and a denoising method and device thereof, relates to the technical field of denoising and is intended to reduce denoising cost and enhance denoisingeffect. The method herein includes: allowing a denoising controller to receive a reference noise signal acquired and transmitted by a reference noise sensor in a target denoising module, and receive an error noise signal acquired and transmitted by an error noise sensor in the target denoising module, wherein the target denoising module is nay of at least two denoising modules; the denoising controller processes the reference noise signal of the target denoising module and the corresponding error noise signal so as to acquire a corresponding target denoising signal of the target denoising module; the denoising controller controls a speaker in the corresponding denoising module according to the target denoising signal to output a denoised sound, so that the denoised sound counteracts noiseto be eliminated.

The invention discloses a method and system based on jet flow for reducing noise of rotor wings. The method comprises the steps of acquiring rotor wing parameters and working parameters of a helicopter; acquiring the thickness noise characteristics of a first rotor wing at an observation point; obtaining the thickness noise characteristics of a plurality of second rotor wings at the observation point; determining an objective function, wherein the objective function is a function which maximizes the area of a noise reduction region of the observation point; determining the distribution position of applied external force according to the objective function; determining the value of the external force according to a sound field cancellation method; adopting a CFD numerical simulation methodfor determining a function relationship of the jet flow parameters and the external force; determining the jet flow parameters of the distribution position according to the function relationship of the jet flow parameters and the external force and the value of the external force; applying the jet flow to the distribution position according to the jet flow parameters to reduce the noise of the rotor wings of the helicopter. By means of the method and system, the area of the noise reduction region of the thickness noise of the rotor wings can be significantly increased, and the noise reductioneffect is improved.

The embodiment of the invention discloses a rotor wing thickness noise control method based on variable area resistance sheets and relates to the technical field of aeroacoustics. Rotor wing thickness noise can be remarkably reduced in a targeted mode. The method comprises the steps that the rotor wing size and flight parameters are read, and rotor wing thickness noise P'T in a given flight state is calculated; a control force F is exerted at the quarter chord wire position of the end of each blade, and control source noise p'F produced by the control force F in the given flight state is calculated; according to a rotor wing thickness noise reducing target, an offset factor f is set, and the control force F exerted at the quarter chord wire position of the end of each blade is calculated; the variable area resistance sheet is added at the quarter chord wire position of the end of each blade, the area and control force relations of different resistance sheets are calculated based on a CFD method, and the area of the resistance sheet at the quarter chord wire position of the end of each blade is obtained; the spanwise distribution positions of the control forces are changed, and the areas of the resistance sheets at different positions are calculated; the resistance sheets with corresponding areas are added at the different positions of the blades.

The invention discloses a method and a system for lowering rotor wing noise on the basis of a trailing edge flap. The method comprises the following steps that: obtaining the rotor wing parameter andthe working parameter of a helicopter; obtaining a first rotor wing thickness noise characteristic on an observation point; obtaining a plurality of second rotor wing thickness noise characteristics on the observation point; determining a target function, wherein the target function is a function which enables the area of a denoising region of the observation point to be maximum; according to thetarget function, determining the distribution position of applied external force; according to a sound field compensation method, determining the numerical value of the external force; adopting a CFD(Computational Fluid Dynamics) numerical value simulation method to determine a function relationship between the deflection parameter and the external force of the trailing edge flap; according to the function relationship between the deflection parameter and the external force and the numerical value of the external force, determining the deflection parameter of the trailing edge flap of the distribution position; and according to the deflection parameter of the trailing edge flap, regulating the deflection of the trailing edge flap on the distribution position so as to lower the rotor wingnoise of the helicopter. By use of the method and the system provided by the invention, the area of the denoising region of the rotor wing thickness noise can be obviously increased, and a denoising effect is improved.

The invention discloses a noise reduction type heat-dissipating explosion-proof motor, which comprises a motor casing and a mounting base mounted on the bottom of the motor casing. The interior of the motor casing is provided with a stator winding, and the front end of the stator winding is driven and connected with a first A rotating shaft, the rear end of the stator winding is connected with a second rotating shaft, and the rear end of the second rotating shaft is fixedly sleeved with a fan, the rear end of the stator winding is installed with a sound insulation board, and the sound insulation board is embedded in the motor In the inner wall of the casing, a plurality of heat conduction pipes are installed annularly through the outer side of the sound insulation board, and the plurality of heat conduction pipes are located at the front end of the sound insulation board. In the present invention, firstly, the combined anti-vibration and noise reduction structure is adopted, which not only improves the noise reduction effect of the explosion-proof motor, but also reduces the noise of the explosion-proof motor and reduces part of the noise reduction cost. It not only has the effect of cooling and dissipating heat, but also improves the sealing protection, reduces the damage to the explosion-proof motor, and improves the service life.