Centrifugal Pump Impeller Blade Channel Width Ratio
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Solution Overview
Problem
Existing closed impellers for centrifugal pumps, particularly in motor vehicle cooling systems, face challenges in achieving optimal hydraulic efficiency, suction behavior, and resistance to cavitation, with complex and costly production processes, and increased wear on downstream components due to cavitation erosion.
Innovation Solution
The design features a continuously increasing blade channel width from inlet to outlet, with a ratio of outlet to inlet width between 1.01 and 1.2, reducing flow velocity and increasing static pressure, thereby relocating cavitation erosion to the impeller made of plastic, which has higher resistance to cavitation, and allowing for one-piece plastic production of impellers with improved hydraulic efficiency and suction behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If closed impellers with three-dimensionally curved blades are used to improve hydraulic efficiency, then hydraulic efficiency increases, but production complexity and cost increase significantly
Solution Approach 1:
The impeller is divided into multiple blade elements arranged in three-dimensional space, where each blade element can be independently defined by coordinates. This segmentation allows complex three-dimensional blade shapes to be constructed from simpler modular elements, facilitating manufacturing while maintaining high hydraulic efficiency.
Solution Approach 2:
The patent transitions from traditional two-dimensional blade profiles to three-dimensionally curved blades by adding a radial dimension to the blade geometry. The blade elements are positioned at different radial distances from the axis of rotation, creating a three-dimensional structure that improves hydraulic efficiency while using standardized manufacturing processes.
2Stress or pressure
If closed impellers with reduced outlet width are used to improve hydraulic performance, then pressure build-up improves, but manufacturing effort increases
Solution Approach 1:
The impeller channel is divided into multiple blade elements with defined spacing, allowing the outlet width to be precisely controlled through the arrangement of discrete elements rather than requiring complex continuous shaping. This segmentation simplifies manufacturing while achieving the desired pressure build-up performance.
Solution Approach 2:
The patent optimizes the outlet width parameter within specific ranges (outlet width to inlet width ratio between 0.6 and 0.8) to achieve effective pressure build-up. By defining acceptable parameter ranges rather than requiring precise single values, the design maintains hydraulic performance while accommodating manufacturing variations and simplifying production.
3Ease of manufacture
If closed impellers with simply curved blades and rectangular flow channel are used to simplify production, then manufacturing is easier, but hydraulic efficiency is limited to maximum 70%
Solution Approach 1:
The patent introduces three-dimensional curvature to the blades by positioning blade elements at different radial distances and angles, transforming the simple two-dimensional geometry into a three-dimensional structure. This dimensional enhancement improves hydraulic efficiency by better guiding the fluid flow while maintaining compatibility with standard manufacturing processes for closed impellers.
Solution Approach 2:
The blade elements are designed with three-dimensional curvature rather than simple planar shapes. The curved surfaces of the blade elements follow optimized flow paths in three-dimensional space, improving hydraulic efficiency by reducing flow separation and turbulence while remaining manufacturable using conventional closed impeller production methods.
4Productivity
If larger outlet width is used to improve delivery rate, then flow rate increases, but suction behavior deteriorates and cavitation risk increases
Solution Approach 1:
The impeller is segmented into multiple blade elements with specific spacing and positioning. This segmentation allows the outlet width to be increased for higher delivery rate while maintaining adequate suction area through the distributed arrangement of blade elements, thereby preventing cavitation and maintaining good suction behavior.
Solution Approach 2:
The patent defines specific parameter ranges for outlet width (ratio to inlet width between 0.6 and 0.8) and blade element positioning to optimize the balance between delivery rate and suction performance. By controlling these parameters within defined ranges, the design achieves high productivity while maintaining reliable suction behavior and minimizing cavitation risk.
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 significantly reduces cavitation wear on downstream components, enhances hydraulic efficiency, and improves suction behavior while simplifying manufacturing and reducing production costs, enabling efficient and cost-effective production of closed impellers with high performance.
Implementation Method 1
centrifugal pumps for conveying homogeneous liquids
Implementation Method 2
an additional cross-sectional increase from the inlet to the outlet of the impeller channel is proposed for conveying gas-containing conveyed media in all practically occurring consistencies in order to deliberately force a negative pressure zone in the channel by detachment, which then promotes the conveyance of gas-containing conveying media in practically all consistencies
Data Source
Figure 1~3
Figure 4~6
Figure 7~9
AI summary
The invention relates to closed impellers (1) for centrifugal pumps used for conveying homogeneous liquids, especially in cooling systems of motor vehicles. The aim of the invention is to develop a novel design of closed impellers (1) for centrifugal pumps used for conveying homogeneous liquids, especially in coolant pumps, such that closed impellers comprising single-curved blades (3) as well as closed impellers comprising three-dimensionally curved blades (3) can be produced at a low cost while the effect of cavitation wear is minimized on the parts/subassemblies that are mounted downstream of the impeller and the hydraulic efficiency as well as the suction behavior of the respective impeller design is significantly improved. Said aim is achieved by a closed impeller (1) for centrifugal pumps which is characterized in that the width of the blade channel continuously increases from the feeding point of the flow into the impeller to the discharge point of the flow from the impeller (1) from a perspective of the meridian section such that the ratio between the width (b2) at the discharge point and the width (b1) at the feeding point ranges from 1.01 to 1.2.