Blade Rotor Pump Stator Channel Design for Cavitation Reduction
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Solution Overview
Problem
Positive displacement pumps with blade rotors face challenges in increasing fluid flow rate while optimizing fluid dynamics and reducing cavitation and noise levels, particularly due to turbulence and vortices caused by the interaction between aspirated and short-circuited fluids.
Innovation Solution
The design incorporates a stator with a first channel that reduces axial thickness and features a deflector to guide fluid flow, minimizing misalignment and fluid-dynamic losses, and a second channel that directs fluid to reduce misalignment between incoming and existing fluid flows, optimizing fluid direction and reducing cavitation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a channel is added to the stator collar to increase fluid flow rate, then the processed fluid flow rate increases, but the axial thickness of the collar must be reduced and fluid-dynamic turbulence increases
Solution Approach 1:
The collar is segmented into multiple functional zones: an aspirating zone with a first channel for fluid intake, a delivery zone with a second channel for fluid discharge, and intermediate transition zones. This segmentation allows independent optimization of each zone's fluid-dynamic characteristics, enabling increased flow rate while maintaining structural integrity and reducing turbulence through controlled transition regions.
Solution Approach 2:
The invention transitions from a conventional single-channel radial flow design to a three-dimensional dual-channel configuration with axial and radial components. The first channel introduces fluid axially while the second channel discharges radially, creating a three-dimensional flow path that increases productivity while distributing pressure more evenly and reducing turbulent mixing that would occur in a single-plane design.
2Productivity
If the collar axial thickness is reduced to accommodate fluid channels, then fluid flow rate increases, but cavitation problems worsen at high speed
Solution Approach 1:
Different regions of the collar are given different local qualities: the aspirating zone features a first channel with specific geometric parameters optimized for fluid intake, while the delivery zone has a second channel with different parameters optimized for discharge. The intermediate zones have gradual transitions with specific curvature radii designed to maintain pressure stability and prevent cavitation, allowing the collar to be thin overall while maintaining reliability in critical regions.
Solution Approach 2:
The collar geometry is designed with preliminary action to prevent cavitation before it occurs. The transition zones between channels are shaped with specific curvature radii that gradually guide pressure changes, and the channel entrances and exits are positioned to ensure pressure equilibrium is maintained throughout the fluid path, preventing the formation of cavitation bubbles at high rotational speeds.
3Productivity
If fluid channels are added to increase flow rate, then productivity improves, but fluid-dynamic losses and noise levels increase
Solution Approach 1:
All fluid passages in the collar are designed with curved rather than sharp transitions. The channels feature rounded entrances and exits, and the intermediate transition zones have continuous curvature with specifically optimized radius values. This spheroidality eliminates flow separation and reduces turbulence, minimizing energy losses while maintaining high flow rates through the dual-channel configuration.
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 design enhances volumetric performance, reduces cavitation, and decreases noise levels by 4% compared to conventional pumps, improving fluid-dynamic efficiency and pump performance.
Implementation Method 1
The rotor is arranged eccentrically with respect to the stator. During use the blades are pushed against the stator.
Implementation Method 2
Positive displacement pumps with blade rotors comprise a rotor provided with radial slots in which the blades are positioned.
Implementation Method 3
The design incorporates a stator with a first channel that reduces axial thickness and features a deflector to guide fluid flow, minimizing misalignment and fluid-dynamic losses
Implementation Method 4
The interaction between the aspirated fluid in the stator after having passed through said channel and the short-circuited fluid already present in the stator generates turbulence, undesired vortices, disturbances in the local distribution of the pressure. All of the above also causes cavitation problems at high speed.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A positive displacement pump with variable displacement comprising: - a blade rotor (2); - a stator (3) comprising a collar (30) internally of which the rotor (2) can rotate. The collar (30) defines at least a first channel (4) which contributes to an introduction of fluid between the rotor (2) and the stator (3). The first channel (4) reduces an axial thickness of the collar (30) in a zone in which it is fashioned. The first channel (4) directs the fluid so as to reduce a misalignment with a second flow of fluid which is short-circuited by the rotor (2). When displacing from a radially more external position (991) towards a radially more internal position (992), the first channel (4) defines a ramp (99). The ramp (99) reduces the depth of the first channel (4), the depth being measured parallel to the rotation axis (20).