Moisture Separator Trailing Edge Design for Steam Turbine Erosion Control
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Solution Overview
Problem
Existing moisture separators in steam turbine power plants have limitations in separation efficiency, leading to potential erosion and corrosion of turbine components due to entrained water droplets, and require larger spacing between corrugated vanes to prevent re-entrainment, which reduces efficiency.
Innovation Solution
The moisture separator apparatus features corrugated vanes with a planar trailing edge that directs moisture droplets or films to the bottom, eliminating the need for pockets and allowing for closer spacing, thereby increasing separation efficiency by reducing re-entrainment and accumulating water effectively at the trailing edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pockets are added to the corrugated vanes to collect moisture, then moisture collection capability is improved, but device complexity and spacing requirements increase
Solution Approach 1:
The invention extracts the moisture collection function from the corrugated surface by adding a separate planar trailing edge to each vane. This trailing edge acts as a dedicated moisture collection and drainage surface, separating the flow guidance function (corrugations) from the moisture collection function (planar trailing edge), thereby improving moisture collection without complicating the corrugated structure itself.
Solution Approach 2:
The invention adds a new dimensional element - the planar trailing edge surface - to the corrugated vane structure. This creates an additional surface area specifically oriented for moisture collection and drainage, transitioning from a purely corrugated surface to a hybrid structure with both corrugated and planar surfaces, enabling improved moisture removal without increasing spacing between vanes.
2Reliability
If spacing between corrugated vanes is increased to prevent re-entrainment, then separation efficiency is improved, but apparatus volume increases
Solution Approach 1:
The invention extracts the moisture drainage function from the spacing between vanes by providing dedicated drainage paths on the planar trailing edges. This allows moisture to be actively directed to collection points rather than relying on gravity and spacing alone, enabling reduced vane spacing while maintaining separation efficiency.
Solution Approach 2:
The planar trailing edge acts as an intermediary element between the corrugated separation surfaces and the moisture collection system. It provides a controlled pathway for moisture removal, mediating the transition from separation to collection, and enabling tighter vane spacing by preventing random re-entrainment through structured drainage.
3Reliability
If corrugated vanes are used for moisture separation, then separation function is provided, but moisture accumulation at trailing edge causes re-entrainment
Solution Approach 1:
The invention converts the harmful effect of moisture accumulation at the trailing edge into a beneficial drainage mechanism. The planar trailing edge is specifically designed to collect and channel the accumulated moisture away from the vapor flow path, transforming what would be a source of re-entrainment into an active moisture removal feature.
Solution Approach 2:
Instead of trying to prevent moisture accumulation at the trailing edge, the invention inverts the approach by designing the trailing edge specifically to collect and redirect the accumulated moisture. Rather than preventing contact between moisture and trailing edge, it embraces the accumulation and channels it away, effectively preventing re-entrainment through active redirection.
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 separation efficiency, reduces the risk of erosion and corrosion in steam turbines, and minimizes the need for reheating steam, leading to increased turbine operational lifetime and performance.
Implementation Method 1
moisture entrained in the vapor and having greater inertia is trapped in the corrugations
Implementation Method 2
the trailing edge of each vane comprises a means to direct moisture on its surface in the form of droplets and/or films to collect and flow to the bottom end of the vanes' trailing edge
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
A moisture separator for a steam turbine power plant for separating moisture from a flow of vapor or gas comprises a bundle of vanes (3) having a corrugated portion (3a, 3b) and a trailing edge (4). The trailing edge (4) comprises means to collect moisture on the surfaces of the trailing edge (4). These means can include a clip-like attachment (5), or a U-shape of the trailing edge itself. The collection means on the trailing edge (4) contribute to the overall moisture separation efficiency of the moisture separator and a decrease of risk of damage to the steam turbine driven by the steam flow.