Patterned Coating for Turbomachine Rotor Flow Control
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Solution Overview
Problem
Conventional abrasive and abradable coatings on turbomachine rotors fail to prevent undesirable flow patterns such as swirls and tangential flows at rotating/stationary seal locations, leading to diminished turbomachine performance.
Innovation Solution
A patterned abrasive or abradable coating is applied to the outer surface of the rotor body, featuring various patterns like anti-swirl, meshed, channeled, and staggered designs to direct and control the flow of the working fluid, thereby minimizing fluid leakage and optimizing flow patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional abrasive or abradable coatings are applied to the rotor surface, then radial clearances are reduced and seal lifetime is increased, but undesirable flow patterns (swirls and tangential flows) are generated that diminish turbomachine performance
Solution Approach 1:
The coating is applied with varying local properties - different regions of the rotor surface have different coating characteristics (abrasive vs. abradable, different thicknesses, different material compositions) to simultaneously achieve sealing in some areas and flow control in others. This local differentiation allows the coating to perform multiple functions that would be contradictory if applied uniformly.
Solution Approach 2:
The coating is divided into multiple segments or zones with different functions. Some segments provide sealing action while others are designed to control flow patterns. The coating may be applied in discrete regions rather than continuously, allowing different portions to address different aspects of the technical contradiction.
2Reliability
If conventional coatings are applied to reduce radial clearances, then sealing effectiveness is improved, but flow direction control is lost leading to fluid leakage between stages
Solution Approach 1:
Different regions of the coating have different properties - some areas have higher abrasiveness for sealing, while other areas have specific surface characteristics that guide flow direction. The coating thickness, material composition, and surface topology are locally optimized to simultaneously achieve sealing and flow control functions.
Solution Approach 2:
The patterned coating acts as an intermediary element between the rotor and stator that mediates both sealing and flow control. Rather than relying solely on the mechanical seal contact, the coating's patterned structure provides a intermediate layer that guides fluid flow while maintaining the seal, translating between the mechanical sealing function and the aerodynamic flow control function.
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
The patterned coatings effectively reduce fluid leakage between stages, direct fluid flow towards turbine buckets, and enhance turbomachine performance by ensuring a more efficient utilization of the working fluid.
Implementation Method 1
A patterned abrasive or abradable coating is applied to the outer surface of the rotor body... for directing a flow of a working fluid across the turbomachine rotor
Data Source
AI summary
A turbomachine rotor includes: a rotor body having an outer surface; and a patterned abrasive or abradable coating formed over the outer surface of the rotor body, the patterned abrasive or abradable coating for directing a flow of a working fluid across the turbomachine rotor.