Steam Generator Coolant Injection Sections
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Solution Overview
Problem
The complex installation of a partition plate in steam generators requires multiple inspection holes and increases assembly time and cost, while also allowing mixing of recirculating and supplied secondary coolants, which affects thermal efficiency.
Innovation Solution
A steam generator design that eliminates the partition plate by using a tube bundle outer casing with separate injection sections for recirculating and supplied secondary coolants, where the coolant with a higher relative flow rate flows at a lower velocity, and includes flow straightening members and differently sized through holes in tube support plates to minimize mixing, enhancing thermal efficiency and reducing assembly costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a partition plate is installed to separate recirculating water and feedwater, then mixing of the coolants is suppressed and thermal efficiency is improved, but the device complexity increases and assembly time increases
Solution Approach 1:
The invention removes the partition plate from the steam generator structure entirely. Instead of using a physical separating wall, the design relies on the natural flow patterns and positioning of injection sections to prevent mixing of recirculating and supplied secondary coolants, thereby simplifying the device while maintaining thermal efficiency.
Solution Approach 2:
The tube bundle outer casing serves as an intermediary structure that organizes the flow paths of different coolants. By positioning injection sections at specific locations within the casing and using the heat transfer tube bundles as flow guides, the system achieves separation of coolant streams without requiring additional partitioning components.
2Loss of energy
If a partition plate is installed to separate recirculating water and feedwater, then mixing of the coolants is suppressed, but multiple inspection holes must be provided and assembly time increases
Solution Approach 1:
The invention eliminates the partition plate and associated inspection holes, reducing assembly complexity and time requirements while maintaining the functional separation of coolant streams through strategic positioning of injection sections within the tube bundle outer casing.
3Productivity
If the coolant with higher flow rate flows at higher velocity, then the injection is more effective, but mixing with the other coolant increases
Solution Approach 1:
The invention applies different flow velocity characteristics to different coolant streams based on their local requirements. The recirculating secondary coolant is injected at a lower velocity to maintain stable flow patterns and prevent mixing, while the supplied secondary coolant flow rate is optimized for its specific thermal exchange requirements, achieving local optimization of both injection effectiveness and thermal efficiency.
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 improves heat transfer efficiency by preventing coolant mixing, increases steam temperature in the high-temperature heat transfer tube bundle, and decreases steam temperature in the low-temperature bundle, while reducing the need for a partition plate and associated assembly costs.
Implementation Method 1
the recirculating secondary coolant injection section and the supplied secondary coolant injection section are configured such that, of the secondary coolant and the recirculating secondary coolant, the coolant having a higher relative flow rate than the other flows at a lower velocity
Implementation Method 2
a high temperature-side heat transfer tube bundle and a low temperature-side heat transfer tube bundle including a plurality of heat transfer tubes disposed in the tube bundle outer casing
Data Source
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AI summary
A steam generator (140) is provided in which mixing of a recirculating secondary coolant with a secondary coolant supplied from a water supply channel (7) can be suppressed without using a partition plate. The steam generator (140) includes: a tube bundle outer casing (5) disposed with a predetermined provided between the casing and the inner wall of a barrel section (1); a high temperature-side heat transfer tube bundle (20H) and a low temperature-side heat transfer tube bundle (20C) that include a plurality of heat transfer tubes (2) having an inverse U-shape; a tube plate (11) for securing the ends of a plurality of heat transfer tubes (2); a steam-water separator (3) that separates steam and a recirculating secondary coolant from each other; a water supply channel (7) for supplying a secondary coolant to the tube bundle outer casing (5) with the secondary coolant being isolated from the recirculating secondary coolant; a recirculating secondary coolant injection section (5h) for injecting the recirculating secondary coolant toward the high temperature-side heat transfer tube bundle (20H); and a supplied secondary coolant injection section (5c) for injecting the secondary coolant supplied from the water supply channel (7) toward the low temperature-side heat transfer tube bundle (20C), the recirculating secondary coolant injection section (5h) and the supplied secondary coolant injection section (5c) being disposed in the tube bundle outer casing (5) on the side toward the tube plate (11). The recirculating secondary coolant injection section (5h) and the supplied secondary coolant injection section (5c) are defined such that, of the secondary coolant and the recirculating secondary coolant, the coolant having a higher relative flow rate than the other flows at a tower velocity.