Shut-off flap hub flow deflection for torque reduction
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Solution Overview
Problem
Shut-off flaps in water management systems face challenges with high throughflow resistance and vibration due to thicker flap disks needed for high differential pressures, and the presence of hubs in the flow creates vortexes that increase resistance and stimulate vibrations.
Innovation Solution
The integration of flow deflection elements, such as passages and control bridges on the hubs, reduces pressure compensation and vortex formation, and the use of a cover plate with intermediate bridges influences the inflow angle to minimize hydraulic moment and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the flap disk is made thicker to withstand high differential pressure, then the strength is improved, but the throughflow resistance increases
Solution Approach 1:
The invention introduces flow deflection elements that segment the flow path around the hubs, creating multiple smaller flow channels instead of one large obstructed area. This segmentation reduces the overall resistance to flow while maintaining the structural integrity of the hubs.
Solution Approach 2:
Flow deflection elements act as intermediaries between the hubs and the main flow path. These elements guide the flow smoothly around the hubs, preventing direct impingement and reducing turbulence, thereby lowering energy loss without compromising hub strength.
2Ease of operation
If hubs are present in the flow to support drive shafts, then the ease of operation is improved, but vortex formation increases leading to higher resistance and vibrations
Solution Approach 1:
The invention converts the harmful wake area and vortex formation behind the hubs into beneficial flow patterns. Flow deflection elements redirect the flow to follow the contour of the hubs more closely, transforming the previously turbulent wake region into a controlled flow path that reduces resistance and eliminates vortex-induced vibrations.
Solution Approach 2:
The flow deflection elements add a dimensional aspect to the hub design by extending flow guidance in the radial direction. This creates a three-dimensional flow path that wraps around the hubs, effectively eliminating the two-dimensional wake area problem and reducing vortex formation.
3Strength
If the flap disk is made thicker for high differential pressure, then the strength is improved, but the actuating moment increases
Solution Approach 1:
The invention extracts the pressure equalization function from the thick flap disk structure and relocates it to flow deflection elements. By providing alternative flow paths through and around the hubs, the pressure differential acting on the flap disk is reduced, thereby decreasing the actuating moment required while maintaining adequate strength.
4Ease of operation
If hubs with lateral extensions are used to hold drive shafts, then the ease of operation is improved, but vibration stimulation of the pipeline increases
Solution Approach 1:
The invention converts the potentially harmful vortex-induced vibrations into beneficial smooth flow patterns. Flow deflection elements guide the flow to follow the hub contours, eliminating the wake region that causes vibrations. The hub structure remains intact for drive shaft support, but the flow interaction is transformed from harmful to beneficial.
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 solution improves throughflow, reduces actuation moment, and diminishes the risk of vibrations in the shut-off element and the following pipeline by minimizing low pressures and vortexes, enhancing the overall performance of the shut-off flap.
Implementation Method 1
The passages can be run, in a particularly advantageous manner, from the inside of the flap disk through the hubs to the outside of the flap disk. To reduce the formation of the vortexes, a part of the flow can thus be conducted to the outside of the flap.
Implementation Method 2
A pressure compensation between the middle of the flap-shaped shut-off element and the wake area behind the hubs can be attained by means of the flow deflection elements
Implementation Method 3
With such control bridges, the fluid flowing through the shut-off flap can be conducted from the inflow side around the hubs and, in this way, a formation of low pressure behind the flap disk can be prevented.
Data Source
AI summary
A shut-off flap with a flap-shaped shut-off element, which is supported within a housing in such a way that it can swivel around a rotation axis and which contains a flap disk staggered relative to the rotation axis and lateral hubs to hold two drive shafts which are supported in such a way that they can rotate in the housing. In order to make possible an improvement of the throughflow and a reduction of the actuation torque, flow deflection elements are located on the two hubs.