Vertical Multi-Stage Pump Flow Rectification
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Solution Overview
Problem
Vertical multi-stage pumps experience deterioration in suction performance due to swirling vortices that occur when fluid flow changes direction by 90 degrees, particularly with hot water or in highland conditions, leading to fluid loss and reduced efficiency.
Innovation Solution
The pump design includes an inner cylinder member that expands the communication space vertically, an annular wall protruding inside the inner cylinder member, a cylindrical guide extending from the inner cylinder member to the suction port, and swivel prevention plates to rectify the fluid flow and reduce swirling vortices, along with a larger first suction port diameter compared to subsequent stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the flow path changes direction by 90 degrees from horizontal to vertical, then the pump structure is simplified, but swirling vortices occur and suction performance deteriorates
Solution Approach 1:
A guide vane is introduced as an intermediary component between the suction nozzle and the impeller. The guide vane has a curved surface that gradually changes the flow direction from horizontal to vertical, preventing direct 90-degree turning and reducing vortex formation. This mediator component resolves the contradiction by maintaining simple overall structure while eliminating harmful flow patterns.
Solution Approach 2:
The guide vane employs a curved surface geometry instead of sharp angular transitions. The curved surface gradually redirects the fluid flow, smoothing the transition and preventing the formation of swirling vortices that would occur with abrupt directional changes. This curvature principle maintains structural simplicity while improving suction performance.
2Reliability
If the communication space is expanded vertically, then suction performance improves, but the pump height increases
Solution Approach 1:
The guide vane utilizes the vertical dimension to gradually redirect horizontal flow into vertical flow. By employing a three-dimensional curved surface, the flow direction changes progressively through spatial transition rather than requiring a larger vertical communication space. This dimensional approach improves suction performance without significantly increasing pump height.
3Productivity
If the first suction port diameter is increased, then suction efficiency improves, but the pump size increases
Solution Approach 1:
The guide vane modifies the flow parameters (velocity distribution, flow direction, turbulence intensity) before the fluid enters the suction port. By optimizing these flow parameters, the effective suction efficiency is improved without requiring an increase in the suction port diameter, thus maintaining compact pump dimensions.
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 suppresses the deterioration of suction performance by reducing turbulent flow, improving suction efficiency, and extending the pump's lifespan by minimizing wear and fluid loss.
Implementation Method 1
an inner cylinder member interposed between the multi-stage pump chamber and a lower casing and expanding the communication space in a vertical direction
Implementation Method 2
A lot of swirling vortices occur in the fluid when the flow path is changed. These swirling vortices obstruct the flow of fluid
Implementation Method 3
a first swivel prevention plate extending in a radial direction toward a central axis of the rotation shaft, and inside the inner cylinder member, a second swivel prevention plate extending in a radial direction toward a central axis of the rotation shaft
Data Source
AI summary
A vertical multi-stage pump includes a rotation shaft extending in a vertical direction, a plurality of impellers fixed to the rotation shaft, a multi-stage pump chamber accommodating the plurality of impellers and comprising a suction port for a first-stage impeller at a lower end, a lower casing comprising a suction nozzle extending in a horizontal direction and forming a communication space communicating the suction nozzle and the suction port, and an inner cylinder member interposed between the multi-stage pump chamber and a lower casing and expanding the communication space in a vertical direction.