Mixed Flow Compressor with Movable Diffuser for Surge Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Refrigerant compressors in HVAC chiller systems face inefficiencies during surge conditions, where the compressor operates at low capacity and fluid flow lacks sufficient radial velocity, leading to potential backflow and reduced performance.
Innovation Solution
A movable diffuser is integrated into the compressor's outlet, capable of translating between positions to adjust the outlet area, ensuring smooth flow and preventing backflow by increasing fluid velocity during surge conditions, thereby extending the compressor's operating range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor operates at low capacity during surge conditions, then the fluid flow velocity decreases, but this leads to insufficient radial velocity causing backflow and reduced performance
Solution Approach 1:
The patent employs a movable diffuser that can dynamically adjust its position between a first position (non-obstructing) and a second position (partially obstructing the outlet). This dynamic adjustment allows the diffuser to actively control fluid flow characteristics during surge conditions, maintaining sufficient radial velocity even at low compressor capacities, thereby preventing backflow and ensuring stable operation across varying load conditions
Solution Approach 2:
The movable diffuser changes the geometric parameter of the outlet area by translating between two positions. During surge conditions, the diffuser moves to the second position to partially obstruct the outlet, effectively changing the flow area parameter to increase fluid velocity and maintain stable flow patterns, thus resolving the contradiction between low capacity operation and flow stability
2Reliability
If the outlet area is reduced to prevent backflow during surge conditions, then fluid velocity increases, but this requires an additional movable component
Solution Approach 1:
The movable diffuser serves multiple functions: it acts as a flow control device to prevent backflow during surge conditions, serves as a structural component of the compressor outlet system, and can potentially function as a flow straightener or velocity distributor. By integrating these multiple functions into a single component, the patent minimizes the addition of separate parts, thus managing device complexity while achieving reliable backflow prevention
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 movable diffuser effectively manages fluid flow during surge conditions, enhancing compressor performance and operational range by actively controlling the outlet area and maintaining efficient operation at lower capacities.
Implementation Method 1
the movable diffuser is configured to vary an area of the outlet... ensuring smooth flow and preventing backflow by increasing fluid velocity during surge conditions
Data Source
AI summary
A compressor according to an exemplary aspect of the present disclosure includes, among other things, a mixed compression stage having both axial and radial components arranged along a main flow path, and a radial compression stage having an impeller with a plurality of vanes arranged in the main flow path downstream of the mixed compression stage. The impeller is configured to rotate about an axis and has an outlet downstream of the vanes. A movable diffuser is arranged at the outlet, and the movable diffuser is configured to vary an area of the outlet.