Centrifugal Pump Intake Grooves for Vortex Dissipation
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Solution Overview
Problem
Centrifugal pumps with high specific velocity experience a significant locally limited increase in net positive suction head (NPSH) curve and instability in the delivery range, primarily due to the formation of a partial load vortex, which affects impeller performance and efficiency, and existing solutions like J-grooves are complex, noisy, and reduce peak efficiency.
Innovation Solution
The introduction of elongated grooves in the intake channel wall surface of centrifugal pumps, connected exclusively to the intake channel, which dissipate the energy of the partial load vortex through friction, reducing its intensity without affecting normal operation or efficiency, and can be easily retrofitted into existing pumps using modular inserts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If J-grooves are used to reduce partial load vortex, then vortex intensity is reduced, but peak efficiency declines and manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating grooves only in specific regions of the impeller suction surface - particularly at the leading edge and in the suction channel area where the partial load vortex forms. This localized groove placement targets the harmful vortex while leaving other critical areas of the impeller unchanged, thus maintaining peak efficiency at the design operating point while reducing vortex intensity at part load conditions.
Solution Approach 2:
The groove structure is segmented into multiple discrete grooves rather than a continuous modification. These segmented grooves are distributed around the impeller circumference at specific angular positions, allowing selective intervention in the flow field. This segmentation enables the grooves to disrupt the vortex formation locally without affecting the overall impeller hydrodynamics at design condition.
2Object-affected harmful factors
If J-grooves are used to reduce partial load vortex, then vortex intensity is reduced, but device complexity increases
Solution Approach 1:
The grooves are implemented as simple surface features on the impeller casting or machining, rather than complex three-dimensional structures. This local quality approach keeps the modification minimal and compatible with standard manufacturing processes, avoiding the need for complex tooling or assembly steps while still achieving vortex reduction.
3Object-affected harmful factors
If J-grooves are used to reduce partial load vortex, then vortex intensity is reduced, but noise and vibration increase
Solution Approach 1:
The grooves are designed with specific dimensional characteristics - shallow depth, controlled width, and optimized angular distribution - that allow them to dissipate vortex energy through friction and turbulence in a controlled manner. This local quality design ensures that the vortex energy is converted to heat rather than being converted to noise and vibration, unlike some other vortex control methods.
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 effectively reduces the intensity of the partial load vortex, improving NPSH performance and stability of the centrifugal pump's characteristic curve without impacting normal operation or efficiency, and can be applied to both new and existing pumps with minimal manufacturing complexity.
Implementation Method 1
The introduction of elongated grooves in the intake channel wall surface of centrifugal pumps, connected exclusively to the intake channel, which dissipate the energy of the partial load vortex through friction
Data Source
AI summary
A centrifugal pump with a housing having one or more impellers having an axial or semiaxial, open or closed design disposed therein and an intake channel mounted upstream of the first impeller. A plurality of grooves that are distributed around the circumference and extend in the direction of flow are arranged within the wall area of the intake channel. In the housing wall of the intake channel there is a closed annular wall area constructed between a point of entry of the first impeller and the proximate ends of the grooves, whereby the grooves are operatively connected exclusively with the space in the intake channel.