Microporous Silencer Structure for Compact Compressor Noise Reduction
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Solution Overview
Problem
The noise attenuation performance of existing silencing devices using the Helmholtz resonator principle is limited by the requirement for a large inner diameter of through-holes and a corresponding volume, which restricts installation sites in centrifugal compressors due to the need for sufficient wall thickness for strength, and current devices can only be installed on planar inner wall surfaces.
Innovation Solution
A silencing device with fine through-holes (0.01 mm to 0.5 mm diameter) and a cavity on the reverse surface of a flow path forming plate, allowing noise reduction using the Helmholtz resonator principle, with the option to stack microporous plates for precise formation of long through-holes and reduced thickness, and an outer peripheral wall to define the cavity shape independently of the casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a silencing device with a large through-hole inner diameter is used to ensure noise attenuation performance, then the noise reduction effect is improved, but the device requires a large space volume which limits installation sites in the casing
Solution Approach 1:
The invention changes the parameter of through-hole diameter from conventional large size to fine size (0.01 mm to 0.5 mm). This parameter change allows the silencing device to achieve effective noise attenuation while requiring minimal space volume, enabling installation in locations with limited space within the centrifugal compressor casing.
Solution Approach 2:
The invention segments the flow path forming plate into multiple microporous plates stacked together. Each plate contains fine through-holes, and by stacking multiple plates, the device achieves the required noise reduction performance in a compact configuration that fits within the limited space of the casing.
2Strength
If the wall thickness of the casing is increased to ensure strength after disposing multiple impellers, then the structural strength is improved, but the available space for installing silencing devices is reduced
Solution Approach 1:
The invention changes the through-hole diameter parameter to a fine size range (0.01 mm to 0.5 mm), which dramatically reduces the space required for the silencing device. This allows installation in the limited space remaining after the casing wall thickness is increased to accommodate multiple impellers and ensure structural strength.
3Object-affected harmful factors
If conventional through-holes with large diameter are used, then the noise attenuation is improved, but fluid circulation in the cavity increases causing decline in noise reduction effect
Solution Approach 1:
The invention changes the through-hole diameter to a fine size (0.01 mm to 0.5 mm), which increases the pressure loss and resistance to fluid flow. This prevents fluid from circulating within the cavity, thereby maintaining the noise reduction effect without the energy loss associated with fluid circulation that occurs with larger diameter through-holes.
4Ease of manufacture
If the silencing device is installed only on planar inner wall surfaces, then the installation process is simplified, but the number of available installation sites is limited
Solution Approach 1:
The invention transitions from requiring planar (2D) surfaces to accommodating three-dimensional curved surfaces. The flow path forming plate can be configured to match the curvature of the casing inner wall, allowing installation on non-planar surfaces and significantly increasing the number of available installation sites within the centrifugal compressor.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances noise reduction performance while increasing installation flexibility by reducing the thickness of the silencing device and minimizing noise reduction decline due to fluid circulation, allowing installation on non-planar surfaces and varying shapes.
Implementation Method 1
The silencing device attenuates the noise that is attributable to the fluid which flows through the flow path by using the principle of the Helmholtz resonator
Data Source
AI summary
A silencing device includes: a flow path forming plate having a flow path forming surface for forming a wall surface of a flow path through which fluid flows; and a cavity defining portion for defining a cavity on the reverse surface side of the flow path forming plate, the reverse surface being located on the reverse side of the flow path forming surface. The flow path forming plate has formed therein a plurality of fine through-holes which are configured to provide communication between the flow path forming surface and the reverse surface and which has a diameter from 0.01 mm to 0.5 mm.