Centrifugal Compressor Open Closed Impeller Stages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional centrifugal compressors with multiple closed impellers are limited by the strength of their joints, restricting the number of revolutions and increasing size and cost due to the need for more stages to achieve high compression ratios.
Innovation Solution
A centrifugal compressor design that alternates between closed and open impellers along the axial direction, with open impellers at the front stages and closed impellers at the rear, reducing total impeller weight and allowing higher revolution speeds, thereby improving compression efficiency and reducing the number of stages needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If closed impellers are used at all stages, then the impeller structure is stronger and can withstand higher centrifugal force, but the number of revolutions is limited and the compressor size and cost increase due to more stages being required
Solution Approach 1:
The impeller sequence is segmented into different types: open impellers at front stages and closed impellers at rear stages. This segmentation allows each type to perform its optimal function - open impellers reduce weight for high-speed operation at front stages, while closed impellers provide structural strength at rear stages where the fluid volume is smaller and compression ratio is higher.
Solution Approach 2:
Different impeller structures are applied at different locations along the axial direction. Front stages use open impellers with lower weight characteristics, while rear stages use closed impellers with higher strength characteristics. This local differentiation optimizes the overall system performance by matching impeller properties to local operating conditions.
2Strength
If closed impellers are used at all stages, then the impeller can withstand higher centrifugal force, but the compressor size and manufacturing cost increase due to increased number of stages
Solution Approach 1:
The multi-stage compressor is segmented into front stages with open impellers and rear stages with closed impellers. This segmentation reduces the total number of stages needed by allowing higher operational speeds in the front stages, thereby reducing overall device complexity while maintaining the required compression ratio.
Solution Approach 2:
The impeller type parameter is changed along the axial direction from open to closed. This parameter change enables the system to achieve the same compression ratio with fewer stages by optimizing the operational parameters (speed, weight) at different locations in the compression process.
3Productivity
If the number of stages is increased to achieve high compression ratio, then the compression efficiency improves, but the compressor size and installation space increase
Solution Approach 1:
The impeller type parameter is varied along the axial direction to optimize compression efficiency. By using open impellers at front stages and closed impellers at rear stages, the system achieves high compression ratios with fewer stages, thereby reducing the overall compressor size and installation space while maintaining high productivity.
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 design increases the number of revolutions, enhances compression efficiency per stage, and minimizes the overall size and cost of the compressor by reducing the number of stages required, while maintaining high compression ratios.
Implementation Method 1
a plurality of impellers that rotate along with a rotation shaft to pump a fluid by using a centrifugal force are provided at a plurality of stages along an axial direction to compress, in a stepwise manner, the fluid sucked in from a suction port
Data Source
AI summary
A centrifugal compressor, in which a plurality of impellers that rotate along with a rotation shaft to pump fluid by using centrifugal force are disposed at a plurality of stages along an axial direction to compress, in a stepwise manner, the fluid sucked in from a suction port, the centrifugal compressor including: a closed impeller including a plurality of vanes disposed in a radial manner about the rotation shaft, and a shroud covering the plurality of vanes from radially outside; and an open impeller including a second plurality of vanes without a shroud. The closed impeller is disposed at a rearmost stage in a fluid flow direction. The open impeller is disposed at a stage located immediately after the suction port in the fluid flow direction.