Compressor Stage Guide Vane Internal Cavity De-icing
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Solution Overview
Problem
Existing axial compressor stages face efficiency degradation and stability issues due to clearance vortices at the blade tips and risk of icing in guide vanes, with existing solutions increasing complexity and performance penalties.
Innovation Solution
Incorporating an internal cavity in guide vanes with a hot air inlet and a convergent outlet passage to inject a cooled air jet into the boundary layer, enhancing de-icing and aerodynamic efficiency while reducing vortex formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radial clearance is maintained between the rotor blade tip and the casing to prevent contact, then the reliability and safety of the compressor stage is improved, but clearance vortices are generated that significantly degrade the efficiency and stability margin of the compressor stage
Solution Approach 1:
A jet of air is introduced as an intermediary substance between the rotor blade tip and the casing. This jet acts as a mediator that fills the clearance gap, prevents the formation of harmful vortices, and reduces the adverse effects of the clearance without requiring the blades to contact the casing. The air jet serves as a cushion that maintains both safety and efficiency.
2Reliability
If air is injected into the boundary layer upstream of the rotor blades to energize it and reduce clearance vortices, then the stability margin and efficiency of the compressor stage are improved, but the device complexity and mechanical complexity are increased
Solution Approach 1:
The system uses a portion of the compressed air already present in the system (taken from downstream of the compressor stage) and redirects it through a simplified passage to the boundary layer injection point. The existing compressed air serves the dual purpose of both compression work and vortex suppression, eliminating the need for separate air supply systems and reducing overall device complexity.
3Reliability
If air is injected into the boundary layer to energize it, then the stability margin is improved, but the injected air is hotter than the boundary layer which limits its effectiveness in cooling and energizing the boundary layer
Solution Approach 1:
The temperature parameter of the injected air is modified by allowing it to cool as it travels through the injection passage. The passage design enables heat exchange with the surrounding environment, reducing the temperature of the air before it reaches the boundary layer. This temperature reduction enhances the cooling effect on the boundary layer and improves the effectiveness of vortex suppression.
4Reliability
If electrical devices or angle variations are applied to guide vanes to prevent icing, then the reliability against icing is improved, but the device complexity and weight of the compressor stage are increased
Solution Approach 1:
The air injection system serves multiple functions simultaneously: it energizes the boundary layer to reduce clearance vortices, cools the guide vanes to prevent icing, and improves overall compressor stage efficiency. This multi-functionality eliminates the need for separate de-icing systems, reducing device complexity and weight while maintaining reliability against icing.
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 solution effectively de-ices guide vanes, increases stability margin, and enhances compressor efficiency by injecting a denser, cooled air jet to eliminate clearance vortices and prevent icing, thereby improving overall performance with reduced complexity.
Implementation Method 1
an internal cavity with a hot air inlet to defrost this guide vane
Implementation Method 2
the first outlet passage may converge downstream, thus forming a convergent nozzle to accelerate the air jet
Implementation Method 3
injecting a jet of air into a boundary layer adjacent to the casing upstream of the rotor blades, so as to energize this boundary layer
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to the field of compressors, specifically to a compressor stage (100) comprising at least one casing (101) delimiting an airflow duct (2), a stator (102) comprising a plurality of guide vanes (103) arranged radially about a central axis (X) in the airflow duct (2), and a rotor (104) able to rotate about the central axis (X) with respect to the stator (102) and comprising a plurality of blades (105) arranged radially about the central axis (X) downstream of the guide vanes (103) in the airflow duct (2). Each blade (105) of the rotor (104) extends from a blade root (105a) to a blade tip (105b) further away than the blade root (105a) from the central axis (X), and has a radial clearance (j) between the blade tip (105b) and the casing (101). In order to prevent ice from forming on the guide vanes, and to prevent clearance vortices at the blade tip, at least one of said guide vanes (103) comprises an internal cavity (106) with an inlet (107) for hot air for de-icing this guide vane (103), and the internal cavity (106) has a first outlet passage (108) leading towards a trailing edge (112) of the guide vane (103) so that a jet of air (114) can be injected into a boundary layer (115) adjacent to the casing (101) upstream of the blades (105) of the rotor (104).