Turbine Stator Vane Suction Port Boundary Layer Control
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Solution Overview
Problem
The efficiency of steam turbines is reduced due to energy loss caused by the development of a boundary layer when steam passes through the vicinity of stator vanes, and there is a demand to reduce steam leakage between the stator vane seal fin and the rotor.
Innovation Solution
A steam turbine configuration that includes rotor blades, a casing, and stator vanes with suction portions and ejection ports. The suction portions are designed to draw in the boundary layer and secondary streams, which are then ejected through the ejection ports into the space between the stator vane seal fins, reducing energy loss and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If steam passes through the vicinity of the stator vanes, then the stator vanes can perform their function of changing flow direction, but a boundary layer is formed due to viscosity causing energy loss and efficiency decrease
Solution Approach 1:
The invention extracts the boundary layer from the main flow path by introducing suction ports that draw the boundary layer away from the stator vane surfaces. This separates the harmful boundary layer (which causes energy loss) from the useful main flow, allowing the stator vanes to maintain their flow direction control function while eliminating the energy loss associated with boundary layer development
Solution Approach 2:
The invention applies preliminary anti-action by using suction to prevent the boundary layer from developing and causing harm in the first place. The suction ports actively remove the boundary layer before it can grow and create significant energy losses, countering the viscous effects that would otherwise degrade performance
2Reliability
If the stator vane seal fin is positioned close to the rotor to reduce leakage, then sealing performance improves, but steam leakage between the stator vane seal fin and rotor increases energy loss
Solution Approach 1:
The invention introduces an intermediary mechanism (the suction and ejection system) between the stator vane seal fin and the rotor. The suction ports draw steam toward the seal fin, and the ejection ports deliver this steam into the gap between the seal fin and rotor, creating a controlled flow that enhances sealing performance while preventing harmful leakage and associated energy losses
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 configuration enhances the efficiency of the steam turbine by reducing energy loss and improving sealing performance, leading to a more efficient conversion of steam energy into rotational force.
Implementation Method 1
when steam passes through the vicinity of the stator vanes, a layer of a stream at which the flow velocity is low and which is called a boundary layer is formed because of the viscosity of the steam
Implementation Method 2
a suction portion, through which at least a portion of a working fluid flowing from one side to the other side in a direction along the axis is suckable
Implementation Method 3
an ejection port through which the working fluid introduced through the suction portion is ejected
Data Source
AI summary
A turbine includes: a rotor having a rotor body, and a plurality of rotor blades; a casing covering the rotor; and a plurality of stator blades, wherein the stator blades each include a stator blade body having formed on the surface thereof a suction part that extends in the radial direction and can suction at least a portion of working fluid, a nozzle inner peripheral member provided inward of the stator blade body in the radial direction, and a plurality of seal fins protruding inward in the radial direction from the inner peripheral surface of the nozzle inner peripheral member, and an ejection port for ejecting the working fluid guided from the suction part is formed in the nozzle inner peripheral member and in a portion of seal fins more on the other side than the seal fin most on one side in the axial line direction.