Wave Energy Venturi Tube Flow Acceleration
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Solution Overview
Problem
Existing wave energy devices, such as those proposed by Bichard and Heck, face challenges in generating sufficient power to justify their construction and maintenance costs, and are not robust enough to withstand ocean surface stresses, particularly due to their design limitations and the slow speed of water flow through submerged turbines.
Innovation Solution
A venturi tube is embedded within an outer cylindrical housing, connected to a buoy via multiple struts, with a throat cross-sectional area optimized to accelerate water flow through the turbine, achieving speeds at least twice that of the water at the venturi mouth but not exceeding the choke speed, thereby enhancing power generation while ensuring device robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a venturi tube is used to accelerate water flow through the turbine, then the power extracted from ocean waves increases, but the device complexity increases
Solution Approach 1:
The venturi tube is embedded within an outer cylindrical housing, creating a nested structure where the inner venturi tube is contained within the outer housing. This nesting approach accelerates water flow through the turbine while containing the complexity within a compact, integrated structure rather than requiring separate components.
Solution Approach 2:
The venturi tube is positioned at a specific location within the housing to create localized water flow acceleration. The throat cross-sectional area is optimized at this specific location to achieve the desired flow velocity increase, applying the quality change locally rather than throughout the entire device.
2Power
If the throat cross-sectional area is reduced to increase water flow speed, then power generation increases, but the risk of cavitation increases
Solution Approach 1:
The throat cross-sectional area ratio is optimized as a key parameter to achieve the desired balance. By carefully selecting this geometric parameter, the design achieves sufficient water flow acceleration for power generation while maintaining pressure conditions that prevent cavitation.
Solution Approach 2:
The design incorporates feedback by ensuring the water flow speed does not exceed the choke speed, which is the maximum speed before cavitation occurs. This feedback mechanism through pressure monitoring and geometric design ensures the system operates within safe parameters.
3Strength
If multiple struts are used to connect the venturi tube to the buoy, then structural integrity against ocean stresses improves, but the device complexity increases
Solution Approach 1:
The connection structure is segmented into multiple struts rather than using a single support element. This segmentation distributes the ocean stresses across multiple load-bearing components, improving overall structural integrity while maintaining a relatively simple modular design.
Solution Approach 2:
The multiple struts are merged with the outer cylindrical housing to form an integrated support structure. This combination approach provides enhanced strength against ocean stresses while avoiding the complexity of completely separate strut assemblies.
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 optimized venturi design significantly increases the power extracted from ocean waves, justifying the costs of construction and maintenance by generating substantially more electricity than previous designs, while maintaining structural integrity against ocean stresses.
Implementation Method 1
a venturi having a mouth and throat disposed in the ocean beneath the flotation device by means connected there between so that the venturi moves responsive to wave action, the cross sectional area of the throat of the venturi relative to the cross sectional of the area of the mouth of the venturi causes water flowing through the throat of the venturi to have a speed of more than two times the speed of the water at the mouth of the venturi but no more than the choke speed of the venturi
Data Source
AI summary
By optimizing the degree to which water is accelerated through a venturi device, the amount of power that an energy device extracts from the ocean is maximized. Prior venturi-based wave energy devices have proven to be inefficient because of the relatively small amount of power that they generate relative to their size and cost. By optimizing the venturi effect created within the submerged venturi components of such devices, the speed of the water moving through the narrowest portions of such a devices is maximized with respect to the wave environments in which they operate, and a maximal amount of energy is extracted from the ocean. This optimization of a wave energy device's power is sufficient to render such devices cost effective. The method of extracting energy from the accelerated flow of water moving through such venturi devices is not limited, and many alternatives exist, each with its own potential benefits.