Variable Stator Vane Curved Surface Leakage Reduction
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Solution Overview
Problem
In variable stator vanes, a high pressure difference between the negative and positive pressure surfaces leads to leakage flow and increased pressure loss due to fluid flow disturbances near the rotation shafts, causing further separation of the flow towards the edge of the stator vane body.
Innovation Solution
A variable stator vane design featuring a curved surface portion on the vane surface adjacent to the radial end surface, with a gradually decreasing curvature radius away from the rotation shaft, and fillet portions with specific curvature radii to minimize leakage flow and pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable stator vane with clearance between the stator vane body and casing is used, then the stator vane can rotate to adjust the angle with respect to the flow direction, but leakage flow is generated from the clearance portion causing disturbance of fluid flow and increased pressure loss
Solution Approach 1:
A curved surface portion is formed on the vane surface adjacent to the radial end surface, with a curvature radius that is gradually decreased with distance away from the rotation shaft. This curved geometry modifies the flow pattern near the clearance, reducing leakage flow and preventing flow separation while maintaining the rotational adjustability of the stator vane.
2Volume of moving object
If the stator vane body is positioned close to the rotation shaft, then the structure is compact, but the flow of fluid is disturbed and pressure loss increases due to the high pressure difference between pressure surfaces
Solution Approach 1:
The curved surface portion with gradually decreasing curvature radius creates a smoother flow transition near the rotation shaft, reducing the adverse effects of the high pressure difference and preventing flow separation even when the stator vane is positioned compactly close to the rotation shaft.
Solution Approach 2:
The curved surface portion is localized at specific positions on the vane surface adjacent to the radial end surface, providing targeted flow control exactly where the flow disturbance and pressure loss occur, without affecting the overall compact structure.
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 curved surface portions reduce fluid flow disturbances and leakage, effectively suppressing pressure loss and preventing an increase in leakage flow, enhancing the efficiency of the compressor.
Implementation Method 1
a curved surface portion which is formed on the vane surface adjacent to the radial end surface protruding radially outward from a circumference of the first rotation shaft, wherein a curvature radius of the curved surface portion is gradually decreased with distance away from the first rotation shaft
Data Source
AI summary
A variable stator vane includes: a stator vane body which includes a radial end surface forming a clearance between the radial end surface and an outer peripheral surface of an inner casing; a rotation shaft which is rotatable so that an angle of the stator vane body with respect to a flow direction of a main stream of a working fluid is varied and which is connected to the radial end surface; and a curved surface portion which is formed on a vane surface adjacent to the radial end surface protruding radially outward from a circumference of the rotation shaft. A curvature radius of the curved surface portion is gradually decreased with distance away from the rotation shaft.