Aerofoil Recesses Mitigate Horseshoe Vortices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gas turbine engines experience significant losses due to the mixing of cooler purge air with hot gases, leading to inefficiencies and weight issues, primarily caused by the formation of pressure side horseshoe vortices and inefficient air flow management.
Innovation Solution
The introduction of recesses between the leading edges of aerofoils and the platform in the aerofoil assembly, which provides an easier escape path for purge air and minimizes interaction with the leading edges, thereby reducing secondary losses and improving efficiency, while also allowing for weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air or purge air is introduced into the wheel space to cool components and restrict hot gas incursion, then cooling effectiveness is improved, but mixing losses increase due to purge air escape into the hot gas path
Solution Approach 1:
The recesses are positioned upstream of the aerofoil leading edges to preemptively guide purge air flow away from the leading edges before the air reaches critical interaction zones. This preliminary flow direction control prevents the formation of horseshoe vortices and reduces mixing losses while maintaining cooling effectiveness
Solution Approach 2:
The recesses act as intermediary flow management structures between the purge air source and the aerofoil leading edges. They provide a transition zone that mediates the purge air flow, directing it away from the leading edges and reducing harmful interactions while preserving the cooling function
2Device complexity
If conventional aerofoil assembly design is used, then structural simplicity is maintained, but secondary losses increase due to pressure side horseshoe vortex formation
Solution Approach 1:
Rather than redesigning the entire aerofoil assembly, the invention applies local modifications in the form of recesses at specific locations upstream of the leading edges. This localized approach reduces secondary losses through improved flow management while maintaining the overall structural simplicity of the conventional aerofoil assembly design
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 recesses in the aerofoil assembly effectively mitigate the formation of pressure side horseshoe vortices, enhance the efficiency of the gas turbine engine, and result in a weight reduction by optimizing the flow of purge air and reducing mixing losses.
Implementation Method 1
The recesses may provide an easier escape path for purge air to leak into a hot gas region with minimal interaction with the leading edges. Maintaining a gap or distance between a flow of purge air and the leading edges may mitigate the formation of pressure side horseshoe vortices.
Implementation Method 2
The consequent mixing of cooler purge air with hot gas results in large mixing losses, due not only to the differences in temperature but also due to the differences in flow direction or swirl of purge air and hot gases.
Data Source
AI summary
An aerofoil assembly includes a platform and a plurality of aerofoils extending radially outward from the platform. The platform has a first edge, a second edge, and a platform surface disposed between the first edge and the second edge. Each aerofoil has a leading edge proximal to the first edge and a trailing edge distal to the first edge. A pitch spacing is defined between the leading edges of adjacent aerofoils along the platform surface. A mid-pitch location is defined midway along the pitch spacing. The platform defines one or more recesses disposed between the leading edges of the plurality of aerofoils and the first edge. Each of the one or more recesses is disposed proximal to the mid-pitch location between adjacent aerofoils.