Compressor Ventilation Chamber for Surge Margin
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Solution Overview
Problem
Conventional turbocharger compressors face challenges in maintaining stability and efficiency, particularly at low flow rates and near surge conditions, where the 'map width enhanced' (MWE) structure can lead to inefficiencies and safety hazards due to hot air discharge and potential debris ingestion through the MWE slot.
Innovation Solution
The design incorporates an enclosed annular chamber with ventilation apertures and conduits that connect to the compressor inlet, allowing for controlled recirculation of air and preventing debris and hot gases from entering the compressor, while maintaining the benefits of increased surge margin and efficiency by ensuring clean air intake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an MWE structure with an open slot is used to increase surge margin, then the compressor can operate stably at lower flow rates, but hot air is discharged through the slot creating safety hazards and debris can be drawn into the compressor
Solution Approach 1:
An enclosed annular chamber is introduced as an intermediary structure between the MWE slot and the external environment. This chamber receives air from the MWE slot and directs it through ventilation conduits to a recirculation point upstream of the compressor inlet, preventing direct discharge of hot air and blocking debris from entering the compressor while maintaining the flow recirculation function
Solution Approach 2:
The ventilation conduits are nested within the compressor housing structure, with the conduits embedded in the housing wall and the annular chamber formed within the housing. This nesting approach integrates the safety and recirculation functions into the existing compressor structure without adding external components
2Reliability
If the inner inlet section length is increased to improve surge margin, then the compressor stability increases, but the compressor efficiency is reduced
Solution Approach 1:
The invention changes the flow path parameters by introducing the annular chamber and ventilation conduits, creating an alternative recirculation pathway that does not require increasing the inner inlet section length. This maintains the original efficient flow path through the impeller while providing an additional controlled recirculation route for surge prevention
3Adaptability or versatility
If the MWE slot is opened to the surrounding environment to improve surge margin, then the compressor map width is increased, but safety hazards arise from hot air discharge and debris ingestion
Solution Approach 1:
The enclosed annular chamber acts as an intermediary that decouples the MWE slot from the external environment. The chamber allows the slot to remain open for flow recirculation purposes while the housing wall and ventilation conduits mediate the interaction with the external environment, filtering out debris and controlling hot air discharge through a safe recirculation path
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 the surge margin by approximately 20% and improves compressor efficiency, while eliminating the risk of debris ingestion and ensuring safe operation by recirculating air through a filtered pathway, thus stabilizing compressor performance across a wider engine speed range.
Implementation Method 1
an elongate ventilation conduit having a first end connected to at least one of the ventilation apertures and a second end connected to a location upstream of the housing inlet
Implementation Method 2
A centrifugal compressor comprises an impeller wheel, carrying a plurality of blades (or vanes) mounted on a shaft for rotation within a compressor housing. Rotation of the impeller wheel causes gas (e.g. air) to be drawn into the impeller wheel and delivered to an outlet chamber or passage
Implementation Method 3
Under these conditions the MWE slot allows the flow to reverse (which is now the prevalent flow regime in parts of the compressor) and to be re-circulated to the intake, thus delaying surge
Data Source
AI summary
A compressor comprises an impeller wheel mounted within a housing defining an inlet and an outlet. The wheel has a plurality of vanes and is rotatable about an axis. The housing has an inner wall defining a surface located in close proximity to radially outer edges of the impeller vanes which sweep across said surface as the impeller wheel rotates about its axis. The inlet comprises a tubular wall extending away from the impeller wheel in an upstream direction. An enclosed chamber is defined between said inner wall and an outer wall and in communication with at least one opening in said in said inner wall. The outer wall is penetrated by at least one ventilation aperture that is designed to be connected via a conduit to a location upstream of the inlet and downstream of an air filter.