Compressor Rotor Bolt-Fixed Impellers for Centrifugal Load Resistance
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Solution Overview
Problem
Centrifugal compressors face issues with impeller damage due to increased centrifugal force at high rotation speeds, as the load concentrates around the shaft insertion hole, leading to instability and potential failure.
Innovation Solution
A rotor design featuring impellers with alternating protrusion and recessed portions in the axial direction, restricted in the circumferential direction, and fixed by bolts through dedicated holes, ensuring stable high-speed operation by distributing the load and preventing impeller shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a large shaft is inserted through a hole in the center of the impeller to fix multiple impellers, then the impellers can be collectively fixed, but the thin portion around the hole cannot withstand the large centrifugal force load at high rotation speeds
Solution Approach 1:
The invention removes the large central shaft and its insertion hole from the impeller structure. Instead, multiple small bolts are used to fix the impellers, eliminating the weak thin portion around the large hole while maintaining the ability to collectively fix multiple impellers through alternative means.
Solution Approach 2:
The fixation system is segmented from a single large central shaft into multiple small bolts distributed around the impeller. This segmentation allows the load to be distributed across multiple points rather than concentrating it around a single large hole, thereby strengthening the impeller against centrifugal forces.
2Ease of manufacture
If a large hole is formed in the center of the impeller for shaft insertion, then the impellers can be fixed by a shaft, but the load due to centrifugal force concentrates on the thin portion around the hole
Solution Approach 1:
The single large central hole is segmented into multiple small bolt holes distributed around the impeller. This distributes the centrifugal force load across multiple locations rather than concentrating it around one large hole, reducing stress on any single thin portion.
Solution Approach 2:
Instead of having a large hole that creates a weak zone across the entire impeller structure, the design uses multiple small localized holes only where needed for bolt insertion. The majority of the impeller structure remains solid and strong, maintaining local quality and strength where it is most needed.
3Reliability
If multiple impellers are fixed by a large central shaft, then they can be held in position, but the impellers may be damaged at high rotation speeds due to increased centrifugal force
Solution Approach 1:
The problematic large central shaft is completely removed from the design. The impellers are instead fixed using multiple small bolts that do not create large weak portions in the impeller structure, allowing the rotor to operate reliably at high speeds without the risk of impeller damage from centrifugal forces.
Solution Approach 2:
The fixation system is divided into multiple small bolt connections rather than one large shaft connection. This segmentation distributes the centrifugal load across multiple points, preventing any single location from experiencing damaging stress concentrations, thereby improving reliability at high rotation speeds.
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 design enhances impeller strength against centrifugal forces, allowing stable high-speed rotation without shaft damage, improves assembly accuracy, and maintains torque transmission, thereby improving the compressor's operational reliability.
Implementation Method 1
each of the plurality of first protrusion portions is fitted into each of the plurality of second recessed portions of another adjacent impeller in a state where movement in the circumferential direction is restricted to each other
Implementation Method 2
a bolt fixing portion having a plurality of bolts that collectively fix the plurality of impellers arranged in the axial direction
Implementation Method 3
a fluid supplied from the outside through the flow path formed in the casing is compressed by rotations of the impellers
Data Source
AI summary
A rotor includes a bolt fixing portion having a plurality of bolts for collectively fixing a plurality of impellers including a disk having a central shaft structure. The disk has a first fitting portion having a plurality of first protrusion portions and first recessed portions, a second fitting portion having a plurality of second protrusion portions and second recessed portions, and a plurality of bolt holes through which the first fitting portion and the second fitting portion pass and into which the bolt is inserted. The first protrusion portion is fitted into the second recessed portion of another adjacent impeller in a state where movement in the circumferential direction is restricted to each other, and the first recessed portion is fitted to the second protrusion portion of another adjacent impeller in a state where movement in the circumferential direction is restricted to each other.