Hydraulic Runner Columnar Member Vortex Suppression
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Solution Overview
Problem
Conventional hydraulic machines experience significant water pressure pulsation due to swirling flows and spiral vortices at partial load operations, leading to inefficiencies and energy loss, as the blades are fixed and unable to adapt to changes in water flow angles, resulting in unconverted energy and pressure drops.
Innovation Solution
The introduction of a columnar member with a diameter smaller than the crown's lower end surface, positioned on the rotation axis below the crown, which acts as a resistance to the expansion/contraction mode of the vortex, suppressing water pressure pulsation by altering the vortex's cross-sectional shape and reducing the occurrence of recirculation regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blades of the runner are fixed, then the structure is simple and reliable, but the energy conversion efficiency decreases at partial load operations due to inability to adapt to changing water flow angles
Solution Approach 1:
The invention introduces movable blades that can change their angle relative to the runner rotation direction. The blades are connected to the runner via a mechanism allowing them to pivot and adjust their orientation dynamically. This enables the blade angle to adapt to different water flow conditions, optimizing energy conversion at both full load and partial load operations while maintaining structural reliability through the controlled movement mechanism.
2Quantity of substance
If the guide vane opening is reduced to adjust flow rate, then the flow rate decreases, but water pressure pulsation increases due to vortex formation in the draft pipe
Solution Approach 1:
The movable blades dynamically adjust their angle to optimize water flow guidance into the runner at different flow rates. By changing blade orientation rather than relying solely on guide vane adjustment, the system maintains smoother water entry conditions that reduce vortex formation and associated pressure pulsations in the draft pipe during partial load operations.
Solution Approach 2:
The invention changes the operational parameters of the runner blades from fixed to variable angle. This parameter change allows the blades to maintain optimal attack angles for water flow at different operating conditions, reducing flow separation and vortex formation that cause pressure pulsation, while still achieving the required flow rate reduction through coordinated guide vane adjustment.
3Stability of the object's composition
If a runner cone is added to suppress vortex, then the vortex suppression improves, but the device complexity and weight increase
Solution Approach 1:
Instead of adding a static runner cone structure, the invention uses dynamically adjustable blade angles to control water flow patterns. By optimizing the blade orientation, the system naturally suppresses vortex formation through improved flow guidance, achieving vortex stability without the added complexity and weight of a runner cone structure.
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
This configuration effectively suppresses water pressure pulsation by reducing the elliptical and rotational modes of the vortex, enhancing energy conversion efficiency and reducing pressure fluctuations, while maintaining low friction loss and weight optimization.
Implementation Method 1
a large spiral vortex 11 due to the swirling flow is generated within the draft pipe 8 in the vicinity of the outlet of the runner 5
Implementation Method 2
the water pressure pulsation of the region 13 is a synthesis of a rotation mode in which a cross-sectional shape of the vortex 11 is an ellipse 14 and rotates with respect to the spiral axis
Data Source
AI summary
In one embodiment, a hydraulic machine includes a runner including a plurality of blades arranged in a ring shape, a crown connected to the blades from an upper side and having a lower end surface at a position surrounded by the blades, and a band connected to the blades from a lower side, the runner being configured to convert energy of pressured water into rotational energy. The machine further includes a main shaft configured to transmit the rotational energy of the runner to a generator, and a draft pipe located downstream of the runner, and configured so that the water used to drive the runner flows into the draft pipe. The machine further includes a columnar member disposed on a rotation axis of the main shaft below the crown, and having a diameter smaller than a diameter of the lower end surface of the crown.