Blade Communication Holes for Fluid Separation Control
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Solution Overview
Problem
Rotary machines face performance deterioration due to fluid separation near blade surfaces, especially when operational conditions deviate from design points, leading to increased loss and inefficiency.
Innovation Solution
A blade design featuring an airfoil portion with communication holes that have first and second opening ends on the pressure and suction surfaces, respectively, allowing pressure differences to drive flow through the holes and reduce separation, with specific geometric configurations to manage static pressure and flow direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional airfoil design is used, then machine performance is maintained at design point, but fluid separation occurs when operational conditions deviate from design point
Solution Approach 1:
The invention changes the geometric parameters of the communication hole (position, orientation, size) to optimize its function. Specifically, the hole is positioned at 40-60% of the airfoil chord length from the leading edge, and oriented at 45-60 degrees relative to the chord line, to effectively control flow separation across varying operational conditions
Solution Approach 2:
The communication hole acts as an intermediary structure that connects the pressure surface and suction surface of the airfoil. It mediates the flow between these surfaces by allowing fluid to pass through, thereby controlling the boundary layer behavior and suppressing separation without requiring external intervention
2Adaptability or versatility
If communication hole is added to suppress fluid separation, then adaptability to operational conditions improves, but device complexity increases
Solution Approach 1:
The invention segments the airfoil structure by introducing a discrete communication hole feature rather than modifying the entire airfoil geometry. This localized modification approach maintains the overall simplicity of the blade while adding separation control functionality through a single geometric element
Solution Approach 2:
The communication hole is positioned at a specific location (40-60% chord length from leading edge) and oriented at a specific angle (45-60 degrees to chord line) to create local flow control exactly where needed. This localized approach suppresses separation at critical regions without requiring global structural changes
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 blade design effectively suppresses fluid separation across a range of operational conditions by utilizing pressure differences to direct flow through communication holes, maintaining aerodynamic performance and reducing loss coefficients.
Implementation Method 1
a pressure difference is apt to occur between the position of the first opening end on the pressure surface and the position of the second opening end on the suction surface when operational conditions of the machine are deviated from a design point. Accordingly, it is possible to generate flow passing through the communication hole from one opening end
Data Source
AI summary
A blade includes an airfoil portion including a pressure surface and a suction surface each extending between a leading edge and a trailing edge along a spanwise direction, and at least one communication hole extending m the airfoil portion and having a first and a second opening end opening to the pressure and suction surface, respectively. The first opening end is located on a first cross-section perpendicular to the spanwise direction at a first position in the spanwise direction, the second opening end is located on a second cross-section perpendicular to the spanwise direction at a second position in the spanwise direction, and a dimensionless blade chord length position of the first opening end with respect to the leading edge on the first cross-section is larger than a dimensionless blade chord length position of the second opening end with respect to the leading edge on the second cross-section.