Centrifugal compressor with liquid injection
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Solution Overview
Problem
Conventional centrifugal compressors in chiller systems experience flow separation and pressure waves at the impeller's trailing edge, leading to compression noise, which existing solutions like isolation covers or micro girth liquid films do not adequately address.
Innovation Solution
Incorporating at least one injection port within the diffuser to supply liquid refrigerant from the condenser or economizer, which injects liquid refrigerant into the diffuser or return channel flow path to suppress flow separation and noise by mixing with high-velocity refrigerant vapor, thereby preventing flow separation from propagating to the diffuser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If liquid refrigerant is injected into the diffuser, then flow separation is suppressed and noise is reduced, but device complexity increases due to additional injection ports and passages
Solution Approach 1:
The injection system is segmented into multiple independent injection ports distributed around the diffuser perimeter, allowing targeted suppression of flow separation at different locations. Each injection port can be independently controlled to optimize noise reduction while minimizing the overall complexity impact through modular design.
Solution Approach 2:
Liquid refrigerant serves as an intermediary substance injected into the diffuser to mediate between the high-velocity vapor flow and the diffuser walls. This intermediary liquid film suppresses flow separation and reduces noise generation without requiring direct modification of the impeller or diffuser geometry.
2Stability of the object's composition
If liquid refrigerant is injected into the diffuser, then flow separation is suppressed, but energy consumption increases due to the phase change and injection process
Solution Approach 1:
The system utilizes phase transition of refrigerant from liquid to vapor within the diffuser to stabilize the flow. The injected liquid refrigerant evaporates in the high-velocity vapor stream, absorbing energy and creating a stabilizing effect that suppresses flow separation and reduces pressure waves.
Solution Approach 2:
The injection system utilizes the existing refrigerant from the condenser or economizer, turning what would be waste refrigerant into a useful flow-stabilizing medium. The system serves itself by using its own refrigerant circulation to solve its own flow stability problems without requiring external energy input.
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 liquid refrigerant injection effectively suppresses flow separation and compression noise by adding energy to the flow and breaking up velocity distinctions within the diffuser, resulting in reduced noise levels and improved operational efficiency.
Implementation Method 1
injects liquid refrigerant into the diffuser or return channel flow path to suppress flow separation and noise by mixing with high-velocity refrigerant vapor
Implementation Method 2
The liquid refrigerant injection effectively suppresses flow separation and compression noise by adding energy to the flow and breaking up velocity distinctions within the diffuser
Data Source
AI summary
A centrifugal compressor for a chiller includes an impeller, a motor, a diffuser, and at least one injection port. The impeller is attached to a shaft rotatable about a rotation axis. The motor is arranged and configured to rotate the shaft in order to rotate the impeller. The diffuser is disposed downstream from the impeller. The at least one injection port is located within the diffuser. The at least one injection port is configured and arranged to supply liquid refrigerant into the diffuser from a condenser or an economizer of the chiller.