Compressor Intake Circumferential Step for Vortex Disruption
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Solution Overview
Problem
Compressors in internal combustion machines, particularly turbocompressors, experience backflow of compressed gas due to incomplete separation of high-pressure and low-pressure chambers, leading to vibration excitation and noise issues like 'discharge hissing', which existing solutions attempt to mitigate with costly air recirculation valves or sound attenuating elements.
Innovation Solution
Integration of a mouth-free circumferential step within the compressor's intake section, oriented transversely to the flow component, to disrupt the vortex flow and reduce backflow, with a step angle of 80° to 100° and a ratio of shortest distance to largest cross-sectional dimension of at least 0.5, effectively disturbing the backflowing vortex flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a turbocompressor design with incomplete separation of high-pressure and low-pressure chambers is used, then high volumetric flows can be delivered, but backflow of compressed gas occurs leading to vibration and noise
Solution Approach 1:
A circumferential step is introduced as an intermediary structure in the intake section that mediates between the high-pressure and low-pressure chambers. This step creates a flow resistance that prevents backflow of compressed gas while maintaining the turbocompressor's high volumetric flow capability, without requiring complete separation of the chambers
Solution Approach 2:
The circumferential step creates a local change in flow characteristics within the intake section. By positioning the step at a specific location with optimized dimensions (step angle of 80° to 100° and specific distance ratios), the backflow is locally disrupted without affecting the overall high-flow performance of the compressor
2Object-generated harmful factors
If air recirculation valves are integrated to prevent backflow, then discharge hissing is avoided, but costs increase significantly
Solution Approach 1:
The circumferential step is a simple, inexpensive geometric feature that can be integrated into the existing compressor housing or intake duct. Unlike expensive air recirculation valves requiring actuators and control systems, this step is a passive structural element that achieves the same noise reduction function at minimal cost
Solution Approach 2:
The invention extracts the essential noise-reduction function from complex active systems (air recirculation valves) and implements it through a simple passive geometric feature (circumferential step). This extraction maintains the beneficial effect while eliminating the complexity and cost of additional components
3Object-generated harmful factors
If sound attenuating elements are integrated upstream of the compressor inlet, then vibration excitation is reduced, but installation space and costs increase
Solution Approach 1:
The circumferential step merges the noise reduction function with the existing intake section structure. Instead of adding separate sound attenuating elements that would increase installation space, the step is integrated directly into the intake duct or compressor housing, achieving vibration reduction without additional space requirements
Solution Approach 2:
The circumferential step serves multiple functions simultaneously: it maintains the high volumetric flow capability of the turbocompressor, prevents backflow of compressed gas, and reduces vibration excitation and noise. This multi-functionality eliminates the need for separate dedicated noise control components
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
The circumferential step significantly reduces vibration excitation and noise generation by disrupting the backflowing vortex flow, thereby minimizing the undesirable noise development known as discharge hissing, without the need for costly additional components or increased installation space.
Implementation Method 1
A backflow of already compressed fresh gas via the compressor impeller into the low-pressure chamber of the compressor can propagate in a wave-like manner, which can lead to a corresponding vibration excitation of the compressor casing
Implementation Method 2
the circumferential step delimiting a flow cross section, wherein a ratio of a shortest distance between the compressor impeller and the circumferential step to a largest cross-sectional dimension in the flow cross section delimited by the circumferential step is at least 0.5
Data Source
AI summary
A compressor for an internal combustion machine includes a compressor impeller rotatably mounted in a compressor casing. A circumferential step is integrated into a wall which delimits an intake section disposed upstream of the compressor impeller in an operating flow direction of a gas to be compressed. The circumferential step is a mouth-free circumferential step which faces the compressor impeller and delimits a flow cross section. A ratio of a shortest distance between the compressor impeller and the circumferential step to a largest cross-sectional dimension in the flow cross section delimited by the circumferential step is at least 0.5. An exhaust gas turbocharger and an internal combustion machine are also provided.