Impeller with External Blades to Reduce Compressor Leakage Loss
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Solution Overview
Problem
HVACR systems experience efficiency losses due to leakage of compressed working fluid through passages between the impeller and housing in compressors, leading to reduced performance.
Innovation Solution
The implementation of external blades on the impeller, which protrude into the leakage passages between the impeller and the housing, creates higher pressures within these passages, reducing the flow rate of compressed working fluid and enhancing sealing by increasing pressure differences across the passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the impeller is spaced apart from the housing to allow rotation, then the impeller can rotate freely, but leakage passages are formed between the impeller and housing causing efficiency losses
Solution Approach 1:
The impeller is segmented into multiple functional components: a hub, a shroud, impeller blades, and external blades. The external blades are segmented from the main impeller structure and positioned to specifically address leakage passages, allowing the impeller to maintain rotation while reducing energy loss through a dedicated sealing mechanism.
Solution Approach 2:
External blades are introduced as intermediary elements between the impeller and the housing. These external blades protrude into the leakage passages and act as mediators to reduce fluid leakage without interfering with the impeller's rotation, thus resolving the contradiction between free rotation and energy efficiency.
2Loss of energy
If external blades protrude into leakage passages, then sealing is enhanced and leakage is reduced, but device complexity increases
Solution Approach 1:
The external blades are merged with the impeller structure, forming an integrated assembly. The external blades can be attached to the hub or shroud, combining the sealing function with the existing impeller components rather than adding completely separate elements, thus reducing overall device complexity while maintaining leakage reduction benefits.
Solution Approach 2:
The external blades serve multiple functions: they seal the leakage passages between the impeller and housing, and they can also contribute to the compression process. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving effective leakage reduction.
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 effectively minimizes fluid leakage through the passages, improving the overall efficiency of the compressor by reducing the flow rate of compressed working fluid and enhancing sealing between the impeller and the housing.
Implementation Method 1
rotating the external blades relative to the housing to increase a pressure within the passage, the increased pressure reducing the flow of compressed working fluid through the passage
Data Source
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AI summary
A compressor includes a housing, a shaft, and an impeller rotatable relative to the housing by the shaft. The impeller includes a hub, impeller blades, and external blades. The impeller blades extend from a front of the hub. The external blades protrude from a rear surface of the hub or an outer surface of a shroud of the impeller. The external blades are curved along the rear surface or the outer surface. A heat transfer circuit includes a compressor and a working fluid. The compressor includes an impeller having a hub, impeller blades, and external blades.