Bypass Pipe Acoustic Load Mitigation in Nuclear Steam Dryers
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Solution Overview
Problem
In nuclear reactors, particularly in boiling water reactors, unbalanced steam flow through steam dryers can lead to acoustic resonance, causing damage to equipment due to excessive acoustic pressures, and existing solutions like Helmholtz resonators are difficult to support in a nuclear environment.
Innovation Solution
A bypass pipe system is introduced, connecting the steam line pipe to the standoff pipe, with a configuration that provides a secondary flow path to cancel acoustic noise by diverting a portion of the acoustic wave out of phase with the main flow, effectively reducing acoustic loads without external support or flow blockage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a Helmholtz resonator is provided on the relief valves to reduce acoustic loading, then the acoustic load on steam dryers is reduced, but the device becomes difficult to support in the nuclear environment due to its large cantilevered bottle-shaped structure
Solution Approach 1:
The invention extracts the acoustic cancellation function from the complex Helmholtz resonator structure and implements it through a simple bypass pipe connection. The bypass pipe takes out only the essential acoustic cancellation capability while eliminating the cumbersome bottle-shaped structure that caused support difficulties.
Solution Approach 2:
The invention creates a simplified acoustic cancellation system that copies the essential function of the Helmholtz resonator using a bypass pipe with specific length and connection points. This copied function achieves acoustic cancellation without requiring the complex original structure.
2Productivity
If steam flow rate is increased to improve power output, then productivity increases, but acoustic resonance damage risk increases due to exceeded breakthrough velocity in dryer vanes
Solution Approach 1:
The bypass pipe system provides preliminary anti-action by canceling acoustic resonance before it can cause damage to the steam dryers. The pipe is configured to generate counter-phase acoustic waves that neutralize the harmful resonance effects, allowing high steam flow rates to be maintained safely.
Solution Approach 2:
The invention converts the harmful acoustic resonance into a beneficial effect by using the same steam flow that causes the resonance to drive the bypass pipe, which then generates counter-phase waves. The harmful acoustic energy is transformed into a protective acoustic cancellation mechanism.
3Strength
If dryer vane configuration is modified to reduce computed stresses from acoustic loading, then structural strength is improved, but the complexity of dryer design and manufacturing increases
Solution Approach 1:
The bypass pipe acts as an intermediary element that reduces acoustic loads on the steam dryers without requiring modifications to the dryer vane configuration. The intermediary pipe system absorbs and cancels the acoustic resonance, protecting the dryers from excessive stresses while maintaining simple dryer design.
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 bypass pipe system passively attenuates acoustic loads, preventing damage to steam dryers and other equipment, facilitating power uprates by eliminating a source of concern for increased acoustic loads, and can be easily integrated into existing nuclear power plants.
Implementation Method 1
A bypass pipe system is introduced, connecting the steam line pipe to the standoff pipe, with a configuration that provides a secondary flow path to cancel acoustic noise by diverting a portion of the acoustic wave out of phase with the main flow
Implementation Method 2
A Herschel-Quincke tube is used to passively cancel acoustic noise at a single frequency. The bypass pipe system passively attenuates acoustic loads
Data Source
AI summary
A system for reducing an acoustic load of a fluid flow includes a first pipe. The first pipe includes a first end and a second end and a first aperture and a second aperture, the first and second apertures being intermediate the first and second ends. A second pipe includes a first end and a second end and a third aperture intermediate the first and second ends. The second pipe is connected at its first end to the first pipe at the first aperture. A bypass pipe includes a first end connected to the second aperture of the first pipe and a second end connected to the third aperture of the second pipe. A method of reducing an acoustic load of a flow in a standpipe connected to a first pipe configured to carry a main flow includes providing a bypass flow from the first pipe to the standpipe.