Kaplan Runner Hub Dry-Air Circulation Against Corrosion
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Solution Overview
Problem
Existing Kaplan turbines face issues with corrosion and reduced lifespan due to water-filled or air-filled hubs, which are not environmentally friendly and lead to corrosion, rusting, and wear, especially when water leaks occur.
Innovation Solution
Implementing a system to generate and circulate dry air with a dew point below 0°C to maintain a dry environment within the runner hub, using dry air to remove moisture and prevent condensation, and monitor humidity levels to detect leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the runner hub is filled with water or air, then the turbine can operate, but corrosion and rusting occur reducing component lifespan
Solution Approach 1:
The patent applies the inert atmosphere principle by filling the runner hub with dry air at positive pressure to create a protective environment that prevents corrosion and rusting of metal components. The dry air acts as an inert medium that displaces moisture and oxygen contact with susceptible surfaces, thereby extending component lifespan while maintaining operational reliability.
Solution Approach 2:
The patent implements parameter changes by controlling the dew point of air within the hub to below 0°C and maintaining positive pressure. These parameter modifications transform the hub environment from a corrosive state (water-filled or humid air) to a protective state (dry air with controlled temperature and pressure parameters), eliminating corrosion while preserving turbine functionality.
2Object-affected harmful factors
If self-lubricated bushings are used in water-filled hubs, then environmental requirements are met, but wear and friction increase due to corrosion
Solution Approach 1:
The patent resolves this contradiction by using dry air at positive pressure within the hub to create an inert environment that protects self-lubricated bushings from corrosion. This allows the bushings to maintain their environmental compliance (no oil contamination) while significantly improving their service life by eliminating water-induced corrosion and reducing friction wear.
Solution Approach 2:
By changing the environmental parameters within the hub - specifically maintaining dew point below 0°C and positive pressure - the patent transforms the operating conditions for self-lubricated bushings from corrosive (water contact) to protective (dry air environment), thereby extending bushing life expectancy while maintaining environmental compliance.
3Ease of manufacture
If air-filled hub is used without air exchange, then installation is simplified, but condensation and water leaks create corrosive environment
Solution Approach 1:
The patent resolves this contradiction by maintaining a continuous supply of dry air at positive pressure within the hub. This inert atmosphere approach prevents condensation by keeping the dew point below 0°C and displaces any moisture from water leaks, thereby eliminating corrosive environments while preserving the installation simplicity of an air-filled system.
Solution Approach 2:
The patent applies parameter changes by controlling the dew point to below 0°C and maintaining positive pressure within the hub. These parameter modifications prevent condensation formation and counteract water leak effects, transforming the hub environment from corrosive to protective while maintaining the ease of manufacture associated with air-filled systems.
4Reliability
If oil is used for lubrication, then friction is reduced, but environmental constraints prohibit its use
Solution Approach 1:
The patent applies the pneumatics principle by using dry air at positive pressure within the hub to create a lubrication-friendly environment for self-lubricated bushings. This pneumatic approach (using compressed dry air) enables self-lubricated components to function effectively without oil, reducing friction and wear while meeting environmental constraints by eliminating hydrocarbon contamination.
Solution Approach 2:
By changing the environmental parameters - specifically maintaining dew point below 0°C and positive pressure - the patent creates optimal conditions for self-lubricated bushings to operate without oil. This parameter control transforms the lubrication system from oil-dependent to self-lubricating, eliminating environmental pollution while maintaining lubrication effectiveness through reduced friction and wear.
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 system effectively prevents corrosion and extends the life of turbine components by maintaining a dry environment, reducing friction and wear, and ensuring consistent critical speed by eliminating humidity and liquid presence.
Implementation Method 1
generating a flow of dry air with a dew point below 0°C; supplying the turbine with the flow of the dry air; evacuating a flow of air out of the turbine after the flow of dry air has flowed at least through the hub
Implementation Method 2
maintaining a dry environment within the runner hub, using dry air to remove moisture and prevent condensation
Data Source
AI summary
A water-fed turbine includes a shaft and a Kaplan runner having a plurality of blades and a hub, the hub located at an end of the shaft and bearing the blades. Means are provided for generating dry air, as well as a means for supplying the turbine with a flow of the dry air. Means are also provided for evacuating air out of the turbine after the flow of dry air has flowed at least through the hub.