Moisture Separator Reheater Pre-Separator Coanda Effect
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Solution Overview
Problem
Existing moisture separator reheaters in nuclear power plants face inefficiencies in moisture removal and potential damage to downstream equipment due to residual liquid droplets, and existing separators are either complex or not optimized for use with reheaters.
Innovation Solution
A moisture separator reheater with a pre-separator that utilizes the Coanda effect by splitting the steam flow into substantially curved pathways, inducing a Coanda effect to attach steam to the bottom wall for enhanced moisture removal efficiency, avoiding flow separation and requiring simpler water collection mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional moisture separator reheaters are used, then steam flow is processed through straight pathways, but moisture removal efficiency is insufficient and liquid droplets damage downstream equipment
Solution Approach 1:
The pre-separator employs substantially curved pathways instead of straight channels to induce the Coanda effect. The curvature causes the steam flow to attach to the bottom wall, creating a sweeping motion that effectively removes moisture droplets from the steam flow before it enters the reheater section, thereby preventing downstream equipment damage.
2Reliability
If complex separator designs are used, then moisture removal capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The separator is divided into two distinct functional sections: a pre-separator section with curved pathways that induces the Coanda effect for initial moisture removal, and a reheater section for steam reheating. This segmentation allows each section to be optimized independently, simplifying the overall design while maintaining effective moisture removal capability.
3Ease of manufacture
If straight pathways are used in the separator, then manufacturing is simpler, but moisture removal efficiency is reduced
Solution Approach 1:
The pre-separator utilizes substantially curved pathways that leverage the Coanda effect to attach steam flow to the bottom wall, creating an efficient moisture removal mechanism. Despite the curvature, the design remains manufacturable by integrating the curved pathways directly into the pre-separator structure, balancing manufacturing feasibility with enhanced moisture removal 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
The solution significantly increases moisture removal efficiency, reduces pressure loss, and prevents equipment damage by ensuring uniform steam distribution and effective droplet capture, making the system more compact and easier to manufacture.
Implementation Method 1
The pre-separator, forming part of the moisture separation-reheater, includes a first pathway and a second pathway with a substantially curved shape so as to induce a Coanda effect in the flow of steam such that the Coanda effect substantially attaches the flow of steam to the bottom wall
Data Source
Figure 1~2
Figure 3~6
AI summary
The present application provides a pre-separator (10) for use with a flow of steam entering a moisture separator reheater. The pre-separator includes a neck (40), an internal baffle (140), a wall (160), a first pathway (110) defined between the neck and the internal baffle (140), and a second pathway (120) defined between the internal baffle (140) and the wall (160). The first pathway and the second pathway create a Coanda effect for the flow of steam entering the moisture separator reheater, wherein the Coanda effect leads to the flow of steam following convex surfaces of the pre-separator.