Vortex Generators for Turbomachine Compressor Flow Control
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Solution Overview
Problem
The existing compressor systems in turbojet engines face significant losses due to recirculation and corner separation, which are not adequately addressed by current solutions that only target one of these issues simultaneously.
Innovation Solution
The implementation of vortex-generating devices that act on both the main flow and recirculation flow, using notches or fins on the upstream face of shrouds to create vortices that accelerate boundary layers and reduce corner separation, thereby addressing both sources of losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If vortex generators are arranged only on the upstream conduit wall to act on the main flow, then corner separation is reduced, but recirculation losses under the stator are not addressed
Solution Approach 1:
The vortex generators are designed to perform multiple functions simultaneously: they act on both the main flow to reduce corner separation and on the recirculation flow to reduce recirculation losses. This multi-functionality resolves the contradiction by making a single device type effective against both harmful phenomena that were previously addressed separately
Solution Approach 2:
The invention introduces a new spatial dimension for vortex generator placement by positioning devices at the outlet of the recirculation cavity rather than only on the upstream conduit wall. This dimensional change allows the vortex generators to interact with both the main flow and recirculation flow, enabling simultaneous reduction of both separation and recirculation losses
2Object-affected harmful factors
If vortex generators are placed upstream of the rectifier to reduce separations, then main flow separation is reduced, but the impact on recirculation flow is insufficient
Solution Approach 1:
The vortex generators are positioned to create vortices that act preliminarily on both the main flow and recirculation flow before these flows interact with the rectifier blades. This preliminary action allows the boundary layers to be accelerated and separations to be reduced in advance, improving overall loss reduction efficiency
Solution Approach 2:
The vortex generators serve as an intermediary element between the recirculation cavity outlet and the main flow, creating vortices that mediate the interaction between these flows. This intermediary action allows simultaneous control of both recirculation and main flow conditions, resolving the contradiction between targeted separation reduction and overall productivity
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
This approach effectively reduces losses by transferring energy from the main flow to boundary layers, minimizing corner vortex and improving compressor efficiency and stability.
Implementation Method 1
each of said individual devices is provided upstream of said assembly so as to act simultaneously on the main flow and on a recirculation flow... vortices are created. These eddies allow a transfer of energy from the main flow to the boundary layers
Implementation Method 2
The boundary layers are then accelerated. Since the low speeds at the bottom of the stator, on the extrados side, in the case of a rectifier, are responsible for the corner vortex, said corner vortex is thus reduced
Data Source
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AI summary
The present invention relates to a bladed (1) assembly (2), particularly a flow straightener, for a turbomachine compressor, said bladed (1) assembly (2) comprising a plurality of individual devices (14A) that have an action on the flow, which are formed in such a way as at least to generate vortices (16). It is characterized in that each of said individual devices (14A) is provided upstream of said bladed (1) assembly (2) so as to act simultaneously on the main flow (E) and on a recirculating flow (G).