Wind Turbine Gear Oil Cooling Circuit Flushing With Pressure Waves
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Solution Overview
Problem
Current methods for cleaning the oil cooling system in wind turbine gearboxes are inadequate, particularly in removing small particles that contribute to increased wear and require high pressures that can damage heat exchangers.
Innovation Solution
A method involving a flushing circuit with a lower viscosity fluid and added air, creating turbulence and pressure waves to dislodge particles from the cooling circuit walls, using a pressure release valve to control pressure up to a safe limit of 3-10 bar, and optionally removing the filter medium to enhance turbulence and sound wave resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high pressure (35-50 bar) is used to create turbulent flow for flushing the cooling circuit, then cleaning effectiveness is improved, but the heat exchanger may be damaged
Solution Approach 1:
The patent applies periodic action by using cyclic pressure waves (sound waves) instead of continuous high pressure. The flushing system generates periodic pressure fluctuations that create turbulence and dislodge particles from heat exchanger surfaces without maintaining constantly high pressure that could cause damage. This periodic action allows effective cleaning while protecting the heat exchanger structure.
Solution Approach 2:
The patent uses pneumatic principles by introducing gas (air or nitrogen) into the flushing liquid to create aerated flushing medium. The gas bubbles expand and collapse during pressure cycles, generating micro-turbulence and cavitation effects that enhance cleaning without requiring high mechanical pressure. This pneumatic approach allows effective particle removal while keeping system pressure below damage thresholds for the heat exchanger.
2Productivity
If high pressure is used to remove particles from cooling circuit walls, then particle removal efficiency is improved, but system safety deteriorates
Solution Approach 1:
The system uses periodic pressure cycles with multiple waves to progressively dislodge and remove particles. Each pressure wave contributes to particle detachment, and the cumulative effect of multiple cycles achieves high removal efficiency without requiring a single dangerous high-pressure event. The periodic nature allows safe pressure levels while maintaining effective cleaning productivity.
Solution Approach 2:
The patent changes the parameters of the flushing medium by aerating it with gas bubbles. This modification allows the flushing liquid to generate turbulence and dislodge particles through bubble dynamics rather than relying solely on high mechanical pressure. The parameter change (adding gas content) enables effective particle removal while keeping the liquid phase pressure within safe system limits.
3Manufacturing precision
If flushing liquid with lower viscosity is used, then turbulence is enhanced and cleaning is improved, but fluid control becomes more difficult
Solution Approach 1:
The system uses pneumatic control to manage the aerated flushing liquid. Gas injection points and pressure regulation valves allow precise control of bubble formation and distribution throughout the cooling circuit. This pneumatic approach enables effective turbulence generation with low-viscosity aerated fluid while maintaining controllable flow patterns through gas pressure regulation rather than relying solely on liquid viscosity control.
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 removes particles smaller than 3 microns from the cooling circuit walls, improving gearbox longevity without damaging the heat exchanger, using lower pressures than previous methods, and enhancing the cleaning efficiency with induced sound waves.
Implementation Method 1
the compressed air expands quickly and creates turbulence in the cooling circuit, which results in cleaning of the inner walls of the cooling circuit
Implementation Method 2
The forceful release creates pressure waves, typically called induced sound waves, in the system that enhances the effect if the turbulence
Implementation Method 3
The cooling circuit comprises a heat exchanger for releasing heat from the gear oil, for example to the environment around the wind turbine
Implementation Method 4
The filter unit comprises a housing inside which there is provided a filter medium for filtering particles from the gear oil when it flows through the filter unit
Data Source
Figure 1~2
Figure 3
AI summary
The cooling circuit (A) for the oil of a gear box (1) in a wind turbine is modified by a flushing circuit (B), which adds air to the oil and raises the pressure in the cooling circuit (A) in order to compress the air prior to a forceful release of the pressure through a pressure release valve (11), which creates turbulence in the cooling circuit (A). The turbulent flow results in cleaning of the inner wails of the cooling circuit (A).