Complex Screw Rotor Helix Profiles to Eliminate Blow Holes
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Solution Overview
Problem
Conventional screw compressors with constant rotor profiles and diameters suffer from radial leakage, blow holes, and inefficient compression due to fixed sealing lines and discharge end clearances, limiting their performance and efficiency.
Innovation Solution
The implementation of variable profile rotors with linear or nonlinear outer diameter changes and helical patterns, designed using rack scaling and interpolation methods, to create a continuously or non-continuously variable helix configuration, reducing leakage and optimizing compression efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If constant rotor profiles and diameters are used, then manufacturing is simpler, but radial leakage and blow holes occur reducing efficiency
Solution Approach 1:
The rotor profile transitions from constant to variable, where different sections of the rotor have different diameters and helical patterns. The variable profile creates optimized sealing lines at different locations, with smaller clearances at critical sealing zones and larger clearances where needed, thereby reducing radial leakage while maintaining manufacturability through systematic design methods.
Solution Approach 2:
The invention changes the rotor profile parameters from constant to variable along the axial length. By varying the outer diameter and helical angle as functions of axial position, the design optimizes compression efficiency and reduces leakage at different stages of the compression process, while using mathematical methods (rack scaling, interpolation) to maintain manufacturability.
2Device complexity
If constant rotor profiles are used, then device complexity is lower, but compression efficiency is reduced due to fixed sealing lines
Solution Approach 1:
The rotor profile transitions from static (constant) to dynamic (variable) characteristics. The variable profile allows the sealing lines and compression chambers to be optimized at different axial positions, creating dynamic compression efficiency that adapts to different stages of the compression process, thereby improving overall productivity while maintaining manageable complexity through systematic design methods.
Solution Approach 2:
The rotor is conceptually segmented into different axial sections, each with optimized profile characteristics. By dividing the rotor into zones with different diameters and helical patterns, the design achieves optimized compression efficiency at each stage while using mathematical methods (rack scaling, interpolation) to maintain overall design coherence and manufacturability.
3Loss of energy
If variable profile rotors are implemented, then radial leakage is reduced, but manufacturing complexity increases
Solution Approach 1:
The invention uses mathematical copying methods (rack scaling, interpolation) to generate the variable profile from a base rack curve. By scaling and interpolating the rack curve coordinates, the complex variable profile is systematically derived, maintaining design coherence and enabling manufacturability through standardized mathematical procedures rather than arbitrary complex geometries.
4Ease of manufacture
If constant outer diameters are used, then discharge end clearances are present causing losses, but rotor manufacturing is simpler
Solution Approach 1:
The outer diameter is varied locally along the axial length, with smaller diameters at the discharge end to eliminate clearance losses. This local optimization reduces port losses and improves compression efficiency at critical zones while maintaining overall manufacturability through systematic variable profile design methods that provide clear manufacturing guidance.
Data Source
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AI summary
A compressor design includes a male rotor having one or more helical lobes and a female rotor having one or more helical grooves. The male rotor is mounted on a first shaft and the female rotor is mounted on a second shaft. The male rotor is positioned in a first section of a chamber and the female rotor is positioned in a second section of the chamber. Fluid enters the chamber at an inlet, and when the rotors are driven, the lobes of the male rotor fit into the grooves of the female rotor, causing compression and movement of the fluid towards an outlet or discharge end where the compressed fluid is discharged. The configuration of the lobe and groove helix, the lobe and groove profile, and the outer diameter of the rotors can be varied in different combinations to form different rotors.