Lobed Butterfly Valve Geometry for Low-Torque Bleed Control
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Solution Overview
Problem
Conventional bleed valves in gas turbines, such as bi-static valves and sliding sleeve valves, fail to provide optimal thermal efficiency and control accuracy, especially during transient operations, and are often associated with higher torque loading and increased manufacturing costs.
Innovation Solution
A butterfly valve with a unique geometry featuring first, second, and third lobes on its valve body, which reduces torque loading while maintaining minimal flow capacity reduction across its operating range, allowing for precise control and improved thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bi-static valves are used for bleeding the compressor, then stepped modulation is achieved, but thermal efficiency is not optimized and control accuracy is reduced
Solution Approach 1:
The butterfly valve replaces the bi-static valve's two discrete positions with a dynamic, continuously adjustable opening mechanism. The valve body can rotate to any angle between fully closed and fully open positions, enabling continuous modulation of bleed air flow. This dynamic control allows precise adjustment of the compressor operating point, optimizing thermal efficiency while maintaining accurate control throughout the operating range.
2Ease of operation
If sliding sleeve valves are used for bleeding the compressor, then boosted stages are controlled, but fine actuation control is difficult
Solution Approach 1:
The butterfly valve employs a simple rotational movement of the valve body around a central axis, replacing the complex linear sliding motion of the sliding sleeve valve. This dynamic rotational actuation provides fine control capability throughout the entire opening range, from fully closed to fully open positions, while significantly simplifying the actuation mechanism and reducing control complexity.
3Productivity
If conventional butterfly valve designs are used, then flow control is achieved, but torque loading is high increasing actuator size and manufacturing cost
Solution Approach 1:
The butterfly valve incorporates a curved perimeter surface on the valve body that is arcuate and extends between the first and second major surfaces. This curved geometry is specifically designed to reduce torque loading by optimizing the flow separation characteristics and pressure distribution around the valve body during rotation, thereby reducing the actuator size and manufacturing cost while maintaining full flow control capability.
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A butterfly valve (50, 50') for a conduit (32) defining a passage (34) for a flow of a fluid therethrough in a flow direction (F1). The butterfly valve (50, 50') includes a shaft (52) rotatably mounted to the conduit (32) and defining a longitudinal axis (LA) along its length. The butterfly valve (50, 50') includes a valve body (100, 100') coupled to the shaft 52, such that the valve body (100, 100') is rotatable along with the shaft (52) about the longitudinal axis (LA) between a closed position (P1) and a fully open position (P2). The valve body (100, 100') includes a first major surface (102), a second major surface (106, 106') opposite to the first major surface (102), a perimeter surface (110), a central plane (CP), a first lobe (116), a second lobe (126, 126'), and a third lobe (132, 132').