Blade Tangential Jet Boundary Layer Control
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Solution Overview
Problem
Conventional fluid-flow machine blades suffer from high pressure losses and inefficient flow redirection due to premature boundary layer separation, limited by unfavorable geometry in existing fluid supply solutions for boundary layer energization.
Innovation Solution
The design incorporates at least one cavity within the blade with a nozzle-type outlet on the suction or pressure side, allowing a tangentially attaching fluid jet to enhance boundary layer stability and flow redirection, featuring a specific shape and orientation to optimize fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional blade profiles are used, then the structure is simple, but premature boundary layer separation occurs causing high pressure losses and inefficient flow redirection
Solution Approach 1:
The blade incorporates a porous or permeable structure with multiple outlets distributed across the blade surface, allowing fluid to be supplied through the blade thickness. This enables boundary layer energization without requiring complex external fluid supply systems, reducing pressure losses while maintaining structural integrity
Solution Approach 2:
The invention uses pneumatic principles by supplying fluid through the blade structure to energize the boundary layer. The fluid supply system uses pressure-driven flow through controlled outlets to maintain attached flow and reduce separation losses
2Temperature
If fluid supply concepts from turbine blades are applied, then surface cooling is achieved, but boundary layer energization is not effective for fluid-flow machines
Solution Approach 1:
The blade design implements different functions at different locations: outlets are strategically positioned and sized to provide boundary layer energization where flow separation is most critical, while other areas maintain structural or cooling functions. The fluid supply is localized to specific regions rather than uniformly distributed
Solution Approach 2:
The fluid supply system is segmented into multiple discrete outlets distributed across the blade surface, allowing independent control and optimization of fluid discharge at different locations. This segmentation enables targeted boundary layer energization without compromising overall blade performance or cooling requirements
3Reliability
If blow-out openings are added to energize the boundary layer, then flow attachment improves, but the geometry design and disposition becomes very difficult
Solution Approach 1:
The invention optimizes outlet parameters such as size, shape, orientation, and distribution pattern to achieve effective boundary layer energization. By carefully selecting and adjusting these geometric parameters, the design achieves reliable flow attachment while maintaining manufacturability through standardized outlet configurations
4Device complexity
If direct passage from pressure side to suction side is used, then fluid supply is simplified, but blade performance values do not significantly increase due to unfavorable passage geometry
Solution Approach 1:
Instead of using simple direct passages through the blade thickness, the invention utilizes the third dimension by creating outlets that extend along the blade surface and are oriented to match the boundary layer flow direction. This dimensional approach allows effective fluid supply without compromising blade performance
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 design significantly improves aerodynamic loadability and efficiency of fluid-flow machines by maintaining or enhancing performance while reducing component count and weight, with potential reductions in specific fuel consumption.
Implementation Method 1
the outlet being designed such that... a fluid jet issuing from the outlet opening essentially tangentially attaches onto the respective surface
Implementation Method 2
to energize the two-dimensional profile boundary layer
Data Source
AI summary
A blade of a fluid-flow machine has at least one cavity 2 arranged in the blade 1, with the cavity 2 connecting to a fluid supply, and at least one outlet opening 3 connecting the cavity 2 to a flow path, in which the blade 1 is arranged. The outlet opening 3 is of a nozzle-type design and essentially inclined in a direction of a main flow extending longitudinally to a corresponding surface of the blade 1. The outlet opening 3 extends over at least a part of the blade 1 height and the outlet opening 3 forms a step in a contour of the blade 1 profile, with a fluid jet issuing from the outlet opening 3 essentially tangentially attaching onto the blade surface.