A muffler for an exhaust system includes an exhaust gas duct pipe (20) and a wall (26). The wall (26) is connected to the exhaust gas duct pipe (20) in a first connection area (24) thereof by a thread meshing.

A muffler includes a first chamber, a second chamber, an extender tube, a reverse flow tube, and a separation chamber. The first chamber is coupled to an exhaust inlet of the muffler. The extender tube is coupled to the first chamber and the second chamber. The exhaust gas flows from the first chamber to the second chamber through the extender tube in a first direction. The reverse flow tube coupled to the second chamber. The exhaust gas flows through the second chamber from the extender tube to the reverse flow tube in a second direction different than the first direction. The separation chamber that provides spatial separation between the first and second chamber.

Example implementations relate to a method and system of cooling a computing system, while simultaneously absorbing airborne noise in the computing system. The computing system includes a chassis having a base and a pair of walls coupled to a peripheral side of the base, and a plurality of rotational drives disposed in the chassis. The computing system includes a frame having a plurality of first openings, and a first acoustic absorber having a plurality of second openings, coupled to the frame to form an acoustic absorber frame. The acoustic absorber frame extends along a lateral direction, disposed downstream relative to the plurality of rotational drives, and coupled to the pair of walls. Each second opening is concentrically aligned to a respective first opening. The computing system includes a plurality of fans coupled to frame and disposed downstream relative to the frame, and aligned to the respective first opening.

In a damping device according to the present invention, a damping device 63 is mounted on a bypass pipe 61 that supplies an amount of high-pressure air to a combustor transition piece 33. The damping device 63 includes a fluid introducing unit 71 that forms a fluid introduction space B by covering an outer peripheral portion of the bypass pipe 61, a plurality of acoustic boxes 73a and 73b that forms resonance spaces Da and Db with the base portions connected to the fluid introducing unit 71 and the end portions extending along the outer peripheral portion of the bypass pipe 61 in the circumferential direction, and partition plates 74a and 74b that form resonance ducts Ea and Eb of a predetermined length by partitioning the resonance spaces Da and Db.

An acoustic metamaterial noise control system of embodiments of the disclosed technology combines acoustic metamaterial principles with absorptive materials, with a result of a significant reduction in sound radiation within, or emanating from, an HVAC duct. Sound waves that impinge on the noise control system placed at the end (terminal opening of an air duct to ambient space within a room/building), or at a predetermined place on the duct, cause the sound waves to reflect back to the start of the noise control system and also to be absorbed by sound waves within the absorptive core. This is accomplished by way of the use of micro-perforated panels (MPPs) placed in periodic manner with absorptive layers and air gaps to achieve anisotropic conditions to reflect and absorb sound waves for optimum sound reduction.

The present disclosure relates to the technical field of aerodynamic and acoustic measurement, in particular to a comprehensive performance test platform for acoustic liner. Based on this comprehensive performance test platform for acoustic liner, the stress of the measured acoustic liner under high sound intensity can be measured by using strain gauges arranged on the measured acoustic liner, the aerodynamic drag of the measured acoustic liner can be measured by using the drag balance, and the acoustic performance parameters of the measured acoustic liner can be calculated based on the sound pressure data obtained by the microphone array. With this test platform, the stress, the aerodynamic drag and the acoustic performance parameters of the measured acoustic liner can be measured simultaneously, which overcomes the problem of inaccurate experimental data obtained in inconsistent experimental conditions caused by conventional separate acoustic liner tests.

Embodiments of the present disclosure provide a diffusion muffling device, a diffusion resonance muffling device, a full-frequency diffusion muffling device, a muffling system for a ventilation channel, and a muffling method using the same, which include a plurality of diffusion muffling units disposed in the ventilation extension direction of the ventilation channel, wherein the plurality of diffusion muffling units are arranged in parallel in a direction with a predetermined angle between the direction and the ventilation extension direction of the ventilation channel, and a muffling passage is formed between each two adjacent diffusion muffling units, wherein each of the diffusion muffling units includes at least one diffuser, and each diffuser includes a plurality of convex portions so that sound waves entering the muffling passage are reflected multiple times in the muffling passage by the plurality of convex portions and then sound is attenuated. In the present disclosure, the diffusers are disposed to diffuse and reflect sound waves, so that the sound is attenuated in a long and narrow passage by multiple times of reflections of the sound waves, thereby improving the low-frequency sound muffling performance in the ventilation channel so as to effectively achieve an effect of sound muffling and noise reduction in ventilation.

Systems and methods are provided for a combined spark arrestor and muffler assembly. In one example, a system may include a combined housing, the combined housing including a spark arrestor portion including a plurality of stator fins, and a muffler portion including acoustic packing, the muffler portion fluidically coupled to the spark arrestor portion via a first sliding joint and a second sliding joint. In this way, a single component of a vehicle exhaust system may reduce sparks and/or carbon deposits in exhaust gas, while also reducing exhaust noise.

According to various embodiments, a mesh assembly may be provided. The mesh assembly may include: a first mesh including a plurality of first holes arranged according to a pattern; a second mesh including a plurality of second holes arranged according to the pattern; wherein the second mesh is provided on top of the first mesh; and wherein at least one hole of the plurality of first holes is at least partially obstructed by the second mesh.

Provided is a structure including a sound absorption section provided in an air flow path on an exhaust side of a fan, traversing a joint portion between a first main housing and a second main housing. The sound absorption section has a double wall structure including an inner wall facing the air flow path and an outer wall spaced outward from the inner wall. A sound absorption member is interposed in a sound absorption chamber between the inner wall and the outer wall of the sound absorption section. A communication hole communicating with the air flow path and the sound absorption chamber is formed in the inner wall of the sound absorption section at a position away from the joint portion.