Controlled Flow Guides for Steam Turbine Leakage Reduction
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Solution Overview
Problem
Steam leakage between the rotating shaft and the circumferentially surrounding turbine casing in steam turbines leads to efficiency losses due to high thermal stresses and profile losses, especially when operating with wet steam, which affects the overall performance and lifespan of the components.
Innovation Solution
The design incorporates controlled flow guides and runners with a high pitch-to-width ratio, Impulse Technology Blading, and a specific back surface deflection angle, along with a shroud arrangement, to minimize leakage and thermal stress by optimizing the steam path and reducing wetness losses through controlled flow management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional turbine blade geometry is used, then manufacturing is simpler, but profile losses and secondary losses increase, reducing efficiency
Solution Approach 1:
The blade geometry is optimized locally with specific pitch-to-width ratios and back surface deflection angles in different regions of the blade to minimize profile losses and secondary losses while maintaining manufacturability
Solution Approach 2:
The invention changes critical geometric parameters including pitch-to-width ratio and back surface deflection angle to optimize steam flow characteristics and reduce losses, achieving 0.2% improvement in dry stage efficiency
2Power
If turbine operates with wet steam, then energy extraction is improved, but wetness losses increase due to non-equilibrium expansion
Solution Approach 1:
The controlled flow guides pre-condition the steam flow before it enters the runner, managing the expansion process to reduce non-equilibrium effects and minimize wetness losses while maintaining energy extraction
Solution Approach 2:
The invention modifies flow parameters through controlled guides, achieving 20% reduction in wetness losses by optimizing the steam expansion characteristics in wet steam conditions
3Power
If steam path components are exposed to high temperatures, then energy conversion is improved, but thermal stresses and hot spots increase, reducing component lifespan
Solution Approach 1:
Controlled flow guides act as intermediaries that manage steam flow and temperature distribution, reducing direct thermal exposure and thermal stresses on critical components while maintaining energy conversion efficiency
Solution Approach 2:
The invention changes thermal parameters through flow control, managing temperature distribution to reduce hot spots and thermal stresses, thereby improving component reliability and lifespan
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 design enhances dry stage efficiency by 0.2% and reduces wetness losses by 20% compared to conventional designs, while safely approaching conventional boundary layer shape factors, thereby improving the steam turbine's operational efficiency and thermal resilience.
Implementation Method 1
Steam generally may flow through a number of turbine stages typically disposed in series through first-stage blades such as guides and runners
Implementation Method 2
the guides may direct the steam toward the respective runners, causing the runners to rotate and drive a load
Data Source
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AI summary
This application provides a steam turbine. The steam turbine may include a number of controlled flow runners and a number of controlled flow guides. The controlled flow guides may include an upstream passage ratio (Wup/ W) of 0.4 to 0.7.