Steam Turbine Blade Root Cooling via Angel Wing Seals
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Solution Overview
Problem
Conventional steam turbines face challenges in withstanding higher steam temperatures, leading to reduced service life due to high thermal stresses on turbine blades and rotor components, which increases maintenance costs and reduces efficiency.
Innovation Solution
The implementation of a steam turbine design with a negative root reaction cooling configuration, where a second steam flow is directed through passageways in the blade roots to enhance cooling, utilizing angel wings and seal configurations to minimize leakage and maximize heat transfer, thereby reducing thermal stresses and extending component life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher steam temperatures are used to increase efficiency, then the efficiency of the steam turbine is improved, but the service life of the turbine is reduced due to high thermal stresses
Solution Approach 1:
The blade root is divided into multiple cooling passages that segment the thermal path, allowing cooler steam to flow through and reduce thermal stresses in critical areas while maintaining high steam temperatures in the working passages for efficiency
Solution Approach 2:
Different regions of the blade root are given different thermal characteristics - some areas receive cooling steam flow while others are insulated, creating local quality variations that protect critical components from thermal stress while maintaining overall efficiency
2Reliability
If temperature resistant materials are used for turbine blades, then the service life is improved, but the cost of the turbine blades increases
Solution Approach 1:
The need for expensive temperature resistant materials is extracted from the solution by introducing a separate cooling steam flow system that actively removes heat from critical areas, allowing the use of more cost-effective blade materials
Solution Approach 2:
Cooler steam acts as an intermediary cooling medium that is introduced into the blade root passages to reduce thermal stresses, serving as a mediator between the hot working steam and the blade structure
3Reliability
If cooling passages are added to blade roots, then thermal stresses are reduced, but the device complexity increases
Solution Approach 1:
The blade root structure serves multiple functions - it provides mechanical attachment and simultaneously houses cooling passages for thermal management, eliminating the need for separate cooling components and reducing overall device complexity
Solution Approach 2:
The cooling passages are nested within the blade root structure itself, with the second steam flow path embedded in the root geometry, creating a compact integrated design that reduces complexity compared to external cooling systems
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 the cooling efficiency of turbine components, increases the operating life of steam turbines, and decreases maintenance and operational costs by effectively managing thermal stresses and improving steam flow utilization.
Implementation Method 1
a second steam flow is directed through passageways in the blade roots to enhance cooling
Implementation Method 2
maximize heat transfer
Implementation Method 3
angel wings and seal configurations to minimize leakage
Data Source
AI summary
A steam turbine is provided. The steam turbine includes a housing, a first steam inlet configured to discharge a first steam flow within the housing, and a second steam inlet configured to provide a second steam flow. A rotor and stator are coupled to the housing and configured to form a first flow path therebetween and in flow communication with the first steam flow. The rotor includes a plurality of blades coupled to the rotor, at least one root of the plurality of blades has a first side, a second side and a passageway coupled in flow communication to the first side and the second side. The passageway is configured to receive the second steam flow within the at least one root. The at least one root includes an angel wing configured to seal the second steam flow from the first flow path.