Stator Platform Leading Edge Profile for Compressor Leakage Control
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Solution Overview
Problem
In axial compressors, leakage flow and impact losses occur due to unreasonable structural design and labyrinth seal inefficiencies, affecting compressor efficiency.
Innovation Solution
The configuration of the stator platform's leading edge is optimized using free jet theory to determine airflow expansion angles and radial height differences, combined with jet hole components and a labyrinth seal to form an aerodynamic wall, reducing leakage flow and impact losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If axial spacing is provided between rotor and stator to prevent axial rub impact, then reliability is improved, but leakage flow enters the cavity structure through the labyrinth seal causing flow loss
Solution Approach 1:
The patent introduces jet holes that utilize the pressure difference across the stator platform to generate counter-flow jets. These jets actively push back against the leakage flow entering through the labyrinth seal, converting the harmful leakage flow into a controlled counter-flow that reduces net leakage into the cavity structure.
2Device complexity
If unreasonable structural form of the platform is used, then device complexity is reduced, but impact loss occurs when gas at the blade root of the previous row impacts on the blade platform of the next row
Solution Approach 1:
The patent optimizes the leading edge profile geometry parameters, specifically the curvature radius and profile shape, to control the flow expansion angle. By changing these geometric parameters, the platform leading edge smoothly guides the leakage flow, preventing abrupt impacts on the next row's blade platform while maintaining relatively simple overall structure.
3Ease of manufacture
If leakage flow at the blade root is not controlled, then ease of manufacture is improved, but flow loss at the blade root of the next row increases significantly
Solution Approach 1:
The patent segments the platform structure by introducing jet holes and dividing the flow control into distinct zones: the labyrinth seal region, the jet hole region, and the leading edge profile region. This segmentation allows each component to address specific flow control needs independently, maintaining manufacturing simplicity while effectively reducing blade root flow loss through the combined action of these segmented features.
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 prevents main flow impact losses and reduces leakage flow, improving compressor efficiency by up to 2.5% compared to conventional designs, especially under low flow conditions.
Implementation Method 1
introducing the high pressure gas at the trailing edge of the stator vane to the blade tip of the labyrinth seal, forming an aerodynamic wall
Implementation Method 2
simplifying a flow of an airflow at a root of a blade of a rotor to a flow of a free jet
Data Source
AI summary
A method includes simplifying flowing of airflow at root of a rotor blade into flowing of free jet, and determining an airflow expansion angle according to Mach number of incoming flow at root of a stator vane; calculating a radial height difference between a first end point on a leading edge of a stator platform and a trailing edge of an adjacent rotor platform by using an axial distance thereof, the angle and a deviation coefficient; determining position of the first end point with radial height difference; determining intersection point of the leading edge and the stator platform as position of a second end point on the leading edge; and determining a profile line between the points by bridging spline curves, so that the tail end thereof is tangent to the intersection line, and the starting end thereof is kept on same plane as side wall of the leading edge.