Turbocharger Compressor Annular Recess Flow Area
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Solution Overview
Problem
Conventional compressors in turbochargers face inefficiencies due to uncontrolled flow of compressed air in clearances between impeller blades and the compressor housing, leading to reduced compressor stage efficiency.
Innovation Solution
Incorporating an annular recess in the diffuser passage of the compressor housing, where the ratio of the outer diameter of the recess to the impeller outer diameter is greater than or equal to 1.1, which increases the flow area and allows for smoother flow of compressed gas, reducing losses in the outlet volute.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the diffuser passage flow area is reduced to minimise clearances between impeller blades and housing walls, then compressor stage efficiency is improved, but the flow area for compressed air becomes insufficient
Solution Approach 1:
The patent introduces an annular recess in the diffuser passage wall that extends in the axial dimension, creating an additional flow pathway. This recess increases the effective flow area of the diffuser passage without requiring an increase in the radial or circumferential dimensions, thereby providing another dimension for flow expansion. The recess allows compressed air to flow smoothly through an extended pathway, reducing losses while maintaining adequate flow area.
2Loss of energy
If clearances between impeller blade tips and compressor housing are minimised, then uncontrolled flow losses are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by creating an annular recess with specific dimensional characteristics (outer diameter L where L/OD ≥ 1.1) in a localized region of the diffuser passage. This recess provides a controlled flow path that addresses the uncontrolled flow issue locally without requiring tight clearances throughout the entire compressor assembly. The recess acts as a dedicated flow management feature that reduces sensitivity to manufacturing variations in blade tip clearances.
3Loss of energy
If the annular recess outer diameter L is increased relative to impeller outer diameter OD (L/OD ≥ 1.1), then flow uniformity and compressor stage efficiency are improved, but the housing complexity increases
Solution Approach 1:
The patent segments the diffuser passage cross-sectional area by introducing an annular recess that creates an additional flow region. This segmentation divides the flow path into distinct zones: the primary diffuser passage and the recessed region. The recess is defined by specific dimensional ratios (L/OD ≥ 1.1) that optimize flow distribution. This segmentation approach improves flow uniformity by creating multiple flow pathways while maintaining a relatively simple overall housing structure.
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 annular recess enhances compressor stage efficiency by promoting uniform flow through the diffuser passage and reducing losses in the scroll section of the outlet volute, as demonstrated by computational fluid dynamics simulations.
Implementation Method 1
the annular recess defining an outer diameter, L; wherein (L/OD) is greater than or equal to about 1.1
Data Source
AI summary
A compressor comprises a housing having an axial intake and an annular outlet volute. An impeller is mounted on a shaft for rotation about a shaft axis between the axial intake and the annular outlet volute. The impeller has a plurality of blades, each blade having a front edge facing the axial intake and a tip. The annular outlet volute includes an annular diffuser passage surrounding the impeller. The annular diffuser passage has a diffuser inlet downstream of the plurality of blades and a diffuser outlet communicating with the annular outlet volute, the tips of the blades sweeping across said diffuser inlet during use. A wall of the housing which defines the annular diffuser passage and which extends over the front edges of the blades defines an annular recess extending from the diffuser inlet towards the diffuser outlet.