Compressor Cover Axial Abutment for Turbine Engine
Solution Overview
Problem
The existing configuration of centrifugal compressors in gas turbines, where the cover's downstream end is free, leads to potential contact with the impeller blades due to pressure variations and vibrations, causing damage and unstable compressor behavior, such as surge, which is harmful but can be mitigated only by increasing clearance at the cost of compressor efficiency.
Innovation Solution
Incorporating a stop mechanism at the downstream end of the cover, which limits axial displacement and maintains a calibrated clearance with the casing, preventing contact with the impeller blades and guiding airflow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the downstream end of the cover is left free to avoid hyperstatic fixing, then the cover can control thermo-mechanical behavior and avoid damaging contact with impeller blades under normal conditions, but during degraded operation with pressure variations and vibrations, the cover deforms and comes into contact with the impeller blades causing damage
Solution Approach 1:
A stop mechanism is introduced as an intermediary element between the cover and the casing. This stop limits the axial displacement of the cover's downstream end, preventing the cover from deforming into contact with the impeller blades during degraded operation, while not interfering with normal cover movement and thermo-mechanical behavior
Solution Approach 2:
The stop mechanism provides preliminary restraint against the harmful deformation of the cover. By pre-positioning the stop at a location that prevents excessive axial displacement, the system counteracts the potential harmful effect of cover deformation before it can occur during surge or unstable compressor conditions
2Object-affected harmful factors
If the clearance between the cover and impeller blades is increased to prevent contact during degraded operation, then contact damage is avoided, but the compressor efficiency is lowered and gas turbine performance is reduced
Solution Approach 1:
The stop mechanism serves as a protective intermediary that prevents cover-to-blade contact without requiring increased clearance. The stop absorbs the protective function, allowing the cover-blade clearance to remain small for optimal compressor efficiency while the stop provides the safety margin during degraded operation
Data Source
Figure 1A
Figure 1B~2
AI summary
The invention relates to a centrifugal compressor of a turbine engine, said compressor including a cover having an upstream end and a downstream end (100b), including: - a casing (30) having an upstream edge and a downstream edge (34); - a blade wheel (20) rotatably mounted in said casing, said cover intended to cover the blades of the wheel so as to define an outer surface of a gas stream extending between the upstream and downstream edges of the casing while being attached to the upstream edge of the casing by the upstream end thereof as the downstream end thereof remains free. The invention is characterized in that the cover (100) also comprises an abutment (102) for limiting the axial movement of the downstream end (100b) relative to the downstream edge (34) of the casing when the compressor is operating.