Steam Turbine Blade Microgrooves for Moisture Erosion Control
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Solution Overview
Problem
Existing steam turbine technologies face challenges in accurately measuring the thickness of water films on turbine stator blades due to high fluid velocities, leading to inadequate removal of moisture and subsequent erosion and braking losses.
Innovation Solution
The implementation of water-repellent microgrooves on the surfaces of rotor and stator blades, which guide condensed water droplets away from the steam flow direction, reducing the likelihood of droplet growth and erosion, and utilizing a film forming substance to enhance water repellency and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric heating is used to remove moisture from turbine stator blades, then moisture removal capability is improved, but measurement precision of water film thickness deteriorates due to high fluid velocities causing large measurement errors
Solution Approach 1:
The patent replaces the electric heating system with a mechanical microgroove structure on the blade surface. These microgrooves passively guide and channel condensed water droplets along the steam flow direction, eliminating the need for active heating and complex thickness measurement systems while effectively preventing droplet accumulation and erosion
Solution Approach 2:
The microgroove structure utilizes the natural flow direction of steam and condensed water to automatically guide water removal without requiring external energy input or control systems. The geometry of the microgrooves themselves provides the moisture removal function through passive fluid dynamics
2Reliability
If water film thickness is measured to optimize heating, then moisture removal is improved, but the system complexity increases due to the need for precise measurement and control systems
Solution Approach 1:
The complex measurement and control system is replaced by a simple mechanical microgroove structure that passively manages water removal through its geometry, eliminating sensors, heating elements, and control electronics while maintaining effective moisture removal
Solution Approach 2:
The microgroove structure performs self-regulated water guidance based on natural condensation patterns and steam flow, requiring no external control systems or power supply
3Ease of manufacture
If conventional smooth blade surfaces are used, then manufacturing is simpler, but erosion increases due to water droplet adhesion and growth on the blade surface
Solution Approach 1:
The blade surface is modified with localized microgroove features in the regions where condensation occurs, while maintaining smooth surfaces elsewhere. This localized structuring provides erosion protection exactly where needed without complicating the overall manufacturing process
Solution Approach 2:
The microgrooves convert the harmful effect of condensed water into a beneficial flow pattern, channeling water droplets along the steam flow direction to prevent accumulation and erosion, effectively transforming the erosion risk into a protective water guidance mechanism
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 effectively prevents the growth of coarse water droplets, reduces erosion, and enhances the efficiency of the steam turbine by minimizing frictional resistance and maintaining water repellency over time.
Implementation Method 1
a plurality of water-repellent microgrooves extending in a steam flow direction are formed on a surface of at least one of the rotor blade and the stator blade
Implementation Method 2
a plurality of water-repellent microgrooves extending in a steam flow direction are formed on a surface of at least one of the rotor blade and the stator blade
Implementation Method 3
utilizing a film forming substance to enhance water repellency and reduce friction
Data Source
AI summary
This steam turbine comprises: a rotating shaft that extends along an axis; a plurality of rotor blades that are arranged in the circumferential direction and that extend in a radial direction from the outer circumferential surface of the rotating shaft; a casing body that covers the rotating shaft and the rotor blades from the outer circumference side; and a plurality of stationary blades that extend in the radial direction from a position on the inner circumferential surface of the casing body on the upstream side of the rotor blades and that are arranged in the circumferential direction. A plurality of microgrooves that extend in the steam flow direction are formed on the surface of the rotor blades and/or the stationary blades.