Rotary Machine Valve Controls Swirl to Reduce Vibration
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Solution Overview
Problem
Steam turbines experience vibration and output decrease due to swirl components in leakage steam, which existing guiding blade technologies attempt to mitigate but often result in reduced rotational force and efficiency.
Innovation Solution
A rotary machine design featuring a recessed portion with a jet flow passage and valve system that adjusts flow conditions to minimize swirl components, allowing for controlled fluid jetting to reduce vibration while maintaining rotational energy, utilizing a vibration detection unit and control device to optimize valve states based on vibration intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If guiding blades are provided in the nozzle portion to decrease swirl components, then vibration of the rotor is restricted, but the frictional force between the rotor and leakage steam decreases, resulting in reduced rotational force and turbine output
Solution Approach 1:
The invention makes the swirl control mechanism dynamic by providing a valve that can switch the jet flow passage between an opening state and a closing state. When vibration occurs, the valve opens to jet fluid into the recessed portion to decrease swirl components and reduce vibration. When vibration is restricted, the valve closes to allow swirl components to pull the rotor in the rotation direction, recovering energy and maintaining turbine output. This dynamic adjustment resolves the contradiction between vibration restriction and power maintenance.
2Stability of the object's composition
If fluid is continuously jetted into the recessed portion to decrease swirl components, then vibration is restricted, but the turbine output decreases significantly
Solution Approach 1:
The invention implements periodic action by using a valve to intermittently control the jet flow into the recessed portion. The valve opens only when vibration is detected and closes when vibration is restricted, creating a periodic rather than continuous jetting action. This allows the system to achieve vibration restriction when needed while minimizing energy loss by allowing energy recovery through swirl components when the valve is closed.
Solution Approach 2:
The invention changes the parameter of fluid flow rate into the recessed portion by switching between opening and closing states of the valve. This parameter change allows the system to adapt to different operating conditions - high flow rate when vibration occurs, and zero or minimal flow rate when vibration is restricted, thereby minimizing energy loss while maintaining vibration control capability.
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
Effectively restricts vibration and minimizes output decrease by managing swirl components, achieving a balance between vibration reduction and maintaining turbine efficiency compared to traditional swirl breakers.
Implementation Method 1
a jet flow passage through which a fluid is jetted rearward in a rotation direction of the rotary shaft in the cavity
Implementation Method 2
a valve which is capable of switching a flow condition of the jet flow passage with turning the valve on an opening state and a closing state
Implementation Method 3
a sealing portion extending from one of a bottom surface of the recessed portion and the tip of the rotor blade, and having a clearance with the other
Data Source
AI summary
There is provided a rotary machine including a rotary shaft; a plurality of rotor blades extending outward from the rotary shaft in a radial direction of the rotary shaft, and are provided with gaps therebetween in a peripheral direction of the rotary shaft; a casing surrounding the rotor blades radially outside the rotor blades, and in which a recessed portion as a cavity accommodates tips of the rotor blades; a sealing portion extending from one of a bottom surface of the recessed portion and the tip of the rotor blade, and having a clearance with the other; a jet flow passage through which a fluid is jetted rearward in a rotation direction of the rotary shaft in the cavity; and a valve which is capable of switching a flow condition of the jet flow with turning the valve on an opening state and a closing state.