Guide Vane Profile Twist for Hydropower Loss Reduction
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Solution Overview
Problem
Existing hydroelectric power plant designs often fail to achieve optimal efficiency due to unsatisfactory results from varying conventional design parameters, leading to inefficient flow management in guide vanes.
Innovation Solution
The guide vane design incorporates a varying skeleton curve end angle along its axial extent, changing from positive to negative, and is inclined relative to the axis of rotation, enhancing flow control and minimizing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional design parameters are varied, then design options can be created, but satisfactory efficiency results are not achieved
Solution Approach 1:
The guide vane is designed with different skeleton curve end angles at different axial positions - a positive skeleton curve end angle in the lower region and a negative skeleton curve end angle in the upper region. This local differentiation of geometric parameters allows optimized flow control at different heights, resolving the contradiction between achieving satisfactory efficiency and improving flow control capability.
Solution Approach 2:
The guide vane leading edge is inclined relative to the axis of rotation, introducing a new geometric dimension. This inclination, combined with the varying skeleton curve end angles along the axial extent, creates a three-dimensional flow control structure that conventional two-dimensional parameter variation cannot achieve, thereby improving both efficiency and flow control capability.
2Stability of the object's composition
If the guide vane has varying skeleton curve end angles, then flow uniformity is improved, but manufacturing complexity increases
Solution Approach 1:
The guide vane employs systematic parameter changes along its axial extent, specifically varying the skeleton curve end angle from positive in the lower region to negative in the upper region. This controlled parameter variation achieves improved flow uniformity while maintaining a regular geometric progression that can be manufactured using standardized processes, balancing flow quality with manufacturing feasibility.
Data Source
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AI summary
The invention relates to a guide vane (1) for a guide wheel of a pump or turbine, comprising a guide vane body. The guide vane body has two end faces (2), a guide vane leading edge (3), a guide vane trailing edge (4), and a first flow-guiding side face (5) and a second flow-guiding side face (5), which connect the guide vane leading edge (3) and the guide vane trailing edge (4) and which form different flow profiles (12) along an axial extent. Said flow profiles each have a chord (8), a mean camber line (9), and a mean camber curve end angle (α) between the mean camber line (9) and the chord (8) at the guide vane trailing edge (4). The guide vane (1) can be rotatably mounted about an axis of rotation (7), which, more particularly is defined by two pivot pins (11). The aim of the invention is to minimize losses in a hydropower system and to achieve high efficiency. To achieve this aim, the guide vane (1) has, along the axial extent, at least one flow profile (12) with a positive mean camber curve end angle (α) and at least one flow profile (12) with a negative mean camber curve end angle (α). The invention also relates to a method for designing a hydropower system, more particularly a pump or turbine, comprising a guide wheel which has guide vanes (1), more particularly a Kaplan turbine or Francis turbine, wherein, by the varying of design parameters, different variants are formed and flow conditions that can be achieved by implementing the individual variants are determined, more particularly by means of a flow simulation or by tests, whereupon, according to flow conditions that can be achieved, one of the variants is selected, more particularly the variant for which an efficiency optimum is achieved.