Centrifugal Compressor Bleed Flow Splitter Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Centrifugal compressors often require a bleed flow that is not readily available from a single source, as the pressure upstream of the impeller is too low for auxiliary use, necessitating a complex bleed flow control arrangement involving multiple sources.
Innovation Solution
An impeller with a plurality of vanes around a hub, featuring a flow stream split that creates an offset between the leading edge and trailing edge, allowing for a mid-impeller bleed location facilitated by a flow splitter, which efficiently captures a desired quantity of bleed flow without complex redesigns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bleed source is used upstream of the impeller, then the device complexity is reduced, but the pressure is too low for auxiliary use
Solution Approach 1:
The impeller vanes are segmented with an offset between leading and trailing edges, creating distinct flow paths that enable a single source to provide both high and low pressure bleed flows through different extraction points
Solution Approach 2:
A flow splitter is introduced as an intermediary component that interfaces with the offset impeller vanes to define a mid-impeller bleed location, enabling efficient capture of bleed flow at the desired pressure level
2Stress or pressure
If multiple bleed sources are used, then the pressure requirement is met, but the device complexity increases
Solution Approach 1:
The offset impeller vane design creates a multi-functional single source that can provide bleed flow at multiple pressure levels (high pressure from trailing edge, low pressure from leading edge) and intermediate levels from the mid-impeller location, eliminating the need for multiple separate bleed sources
Solution Approach 2:
The offset between leading and trailing edges creates a new spatial dimension in the flow path, allowing the flow splitter to access bleed flow at different radial positions and pressure levels from a single impeller source
3Use of energy by moving object
If bleed flow is removed from the impeller, then the dynamic head is improved, but diffusion effects may become detrimental
Solution Approach 1:
The flow splitter is positioned to extract bleed flow locally at the mid-impeller location where the flow conditions are optimal, removing only the necessary amount of flow (1% to 10%) without disrupting the overall diffusion process in other critical areas of the impeller
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 solution enables efficient and low-loss bleed flow recovery, providing a consistent 1% to 10% bleed flow, improving the dynamic head and reducing detrimental diffusion effects, while allowing for significant bleed turndown without lip separation.
Implementation Method 1
a centrifugal compressor assembly generally includes an impeller and a diffuser. The impeller, fixed to a central shaft, rotates about an axis within a stationary impeller shroud
Implementation Method 2
The flow splitter 52 closely follows the shape of a radial forward surface downstream of the offset to define a mid-impeller bleed path
Data Source
AI summary
An impeller includes a plurality of vanes formed around a hub, each of the plurality of vanes defines an offset between a leading edge and a trailing edge.