Vertical Axis Helix Turbine for Very Low Head Hydroelectric Plants
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Solution Overview
Problem
The high cost and large civil engineering requirements for constructing conventional low-head and very low-head hydroelectric power plants, due to the need for large draft tubes to manage high kinetic energy recovery, have limited the construction of such plants.
Innovation Solution
A turbine design for very low-head hydroelectric power plants with a helix-shaped wheel, a carter with a converging and diverging portion, and adjustable blades, allowing for a smaller water intake passage and draft tube, or even their elimination, with a wheel diameter greater than 3 meters and a rotation speed of less than 50 revolutions per minute, optimizing energy conversion and reducing construction costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional Kaplan turbines are used for very low head hydroelectric power plants, then energy conversion efficiency is improved, but the kinetic energy recovery requires very large draft tubes which increases construction cost and civil engineering requirements
Solution Approach 1:
The patent changes the fundamental parameters of the turbine design by using a vertical axis configuration instead of horizontal axis, and by optimizing the wheel diameter and rotation speed relationship. This parameter change allows the turbine to operate efficiently at very low heads without requiring large draft tubes for kinetic energy recovery, as the vertical configuration naturally manages the flow and energy conversion differently.
Solution Approach 2:
The patent inverts the conventional horizontal axis Kaplan turbine design by using a vertical axis configuration. This inversion fundamentally changes how the turbine handles water flow and kinetic energy, allowing for compact draft tube dimensions while maintaining efficient energy conversion at very low head conditions.
2Use of energy by moving object
If the wheel diameter is increased to greater than 3 meters, then the rotation speed decreases to less than 50 revolutions per minute, optimizing energy conversion, but the turbine size increases
Solution Approach 1:
The patent optimizes the relationship between wheel diameter and rotation speed by changing the operational parameters to operate at very low rotation speeds (less than 50 revolutions per minute) with large diameter wheels (greater than 3 meters). This parameter optimization achieves efficient energy conversion at very low heads while managing the turbine volume through controlled design parameters.
Solution Approach 2:
The patent employs adjustable blades that can be dynamically adjusted to optimize the turbine's performance for different operating conditions. This dynamic adjustment capability allows the turbine to maintain optimal energy conversion efficiency across varying flow conditions while managing the overall turbine volume through adaptive blade configuration.
3Ease of manufacture
If the water intake passage and draft tube dimensions are reduced, then construction costs decrease and environmental impact is reduced, but the ability to manage high kinetic energy recovery is compromised
Solution Approach 1:
The patent changes the fundamental approach to kinetic energy recovery by using a vertical axis turbine configuration that naturally manages flow and energy conversion. This parameter change allows for reduced water intake passage and draft tube dimensions while maintaining effective kinetic energy recovery, thereby reducing construction costs and environmental impact without compromising energy management capability.
Solution Approach 2:
By inverting the conventional horizontal axis design to a vertical axis configuration, the patent fundamentally changes how kinetic energy is recovered and managed. This inversion allows for compact passage dimensions while maintaining effective energy recovery, resolving the contradiction between reduced construction scale and maintained energy management 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
The design minimizes the dimensions of the water intake passage and draft tube, decreases construction costs, and allows for efficient energy conversion, making hydroelectric power plants feasible on very low-head sites with reduced environmental impact and no need for additional fish ladders or protection screens.
Implementation Method 1
potential energy stored in the water accumulated in a dam or drawn into a water intake is used to power the wheel of a turbine. The potential energy then turns into mechanical energy.
Implementation Method 2
A turbine (30) for a hydroelectric power plant intended to equip a water stream at the level of a very low head
Implementation Method 3
The turbine, in turn, drives a generator which converts the mechanical energy into electric energy.
Implementation Method 4
Draft tube 18 aims at slowing down the flow coming out of wheel 13 and thus enables recovering as much of the kinetic energy remaining in the flow coming out of turbine 14 as possible.
Implementation Method 5
A distributor 16 is provided in water intake passage 10 upstream of turbine 14 to properly direct the water flow with respect to blades 17 of wheel 13 of turbine 14.
Data Source
AI summary
A turbine for a hydroelectric power plant intended to equip a water stream at the level of a very low head lower than 10 meters, and preferably from 1 to 5 meters, comprising a helix-shaped wheel, the ratio between the kinetic energy of the water flow coming out of the wheel and the potential energy of the head being smaller than 20%.