Compressor Shaft Diameter Ratio for Pressure Build-up
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing compressor arrangements with axial and radial compressors on a common shaft are rotor-dynamically limited in pressure build-up due to natural frequency, stiffness, and damping characteristics, restricting maximum pressure achievement.
Innovation Solution
Increasing the shaft diameter in the axial compressor region to at least 50% larger than the minimum radial impeller seat diameter in the radial compressor region, with a preferred ratio between 1.5 and 3.0, to enhance pressure build-up and reduce construction length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the shaft diameter is increased in the axial compressor region, then the pressure build-up is enhanced and construction length is shortened, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The shaft is designed with different diameters in different regions: a larger diameter in the axial compressor region (ratio 1.5-3.0 compared to radial compressor region) to provide the necessary stiffness and pressure build-up capability, while maintaining a smaller diameter in the radial compressor region to reduce overall complexity and manufacturing difficulty. This localized differentiation resolves the contradiction by applying the larger diameter only where it is most needed for pressure generation.
2Stress or pressure
If the shaft diameter ratio between axial and radial compressor regions is increased to 1.5-3.0, then the pressure build-up capability is significantly improved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention specifies a particular parameter range for the shaft diameter ratio (1.5-3.0) between the axial and radial compressor regions. By optimizing this parameter within a defined range, the patent achieves improved pressure build-up capability while keeping manufacturing precision requirements at acceptable levels. The ratio is not arbitrarily large, which would make manufacturing excessively difficult, but sufficiently large to provide the desired performance improvement.
3Stability of the object's composition
If the shaft diameter is made at least 50% larger in the axial compressor region, then the natural frequency and stiffness are improved, but the weight of the shaft increases
Solution Approach 1:
Instead of uniformly increasing the shaft diameter throughout, the invention applies the larger diameter (50% or more) specifically in the axial compressor region where high stiffness and natural frequency are critical for pressure build-up. The radial compressor region maintains a smaller diameter, reducing the overall weight increase while still achieving the desired improvement in dynamic characteristics where it matters most.
Data Source
AI summary
A compressor arrangement has a common shaft, an axial compressor having at least a single-stage, and a radial compressor having at least single-stage. Assemblies of the, or each, axial compressor stage on the rotor side and assemblies of the, or each, radial compressor stage on the rotor side are attached to a common shaft (4). A ratio between a maximum diameter of the shaft (4) in the region of the axial compressor (2) and a minimum radial impeller seat diameter of the shaft (4) in the region of the radial compressor (3) is between 1.5 and 3.0.