Centrifugal Pump Unit With Non-Circular Outlet Inlet Surface
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Solution Overview
Problem
Centrifugal pumps with contactless magnetically levitated rotors face issues with increased static and dynamic axial and tilting forces, as well as radial disturbance forces, due to the design of the outlet inlet area, which affects efficiency and stability.
Innovation Solution
The pump unit design features a non-circular inlet surface for the outlet, with straight edges and a profile that allows for a larger cross-sectional area without increasing the axial extent, positioning it closer to the blades for reduced disturbance forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the outlet inlet area is designed with a conventional circular profile, then the axial extent is reduced, but the cross-sectional area is limited which increases pressure drop and disturbance forces
Solution Approach 1:
The inlet surface of the outlet is designed with a non-circular profile featuring straight edges instead of a conventional circular shape. This asymmetric geometric configuration allows the inlet surface to achieve a larger cross-sectional area while maintaining a constrained axial extent, thereby reducing pressure drop and disturbance forces on the magnetically levitated rotor without increasing the axial dimension of the pump unit
2Reliability
If the rotor is positioned closer to the blades to reduce disturbance forces, then magnetic bearing stability improves, but the axial extent increases
Solution Approach 1:
Instead of increasing the axial extent to position the rotor closer to the blades, the invention changes the geometric dimensioning approach by using a non-circular inlet surface profile with straight edges. This dimensional reconfiguration allows the inlet surface to extend more in radial directions while maintaining a limited axial extent, enabling reduced disturbance forces and improved magnetic bearing stability without increasing the overall axial length of the pump unit
3Productivity
If the cross-sectional area of the inlet surface is increased to reduce pressure drop, then flow efficiency improves, but the axial extent increases
Solution Approach 1:
The inlet surface employs a non-circular profile with straight edges that optimizes the distribution of flow areas. This asymmetric design allows the cross-sectional area to be maximized for improved flow efficiency and reduced pressure drop while keeping the axial extent constrained, as the area expansion is achieved through radial rather than axial 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 design significantly reduces axial and tilting forces on the rotor, enhancing the magnetic bearing and efficiency of the centrifugal pump by minimizing disturbance forces and pressure drop.
Implementation Method 1
The electrical windings of the stator generate a rotating magnetic field that exerts a torque on the rotor, causing it to rotate around a target axis defined by the axial direction
Implementation Method 2
This field also exerts an adjustable lateral force on the rotor, allowing its radial position to be actively controlled
Implementation Method 3
the rotor is passively magnetically supported and stabilized by reluctance forces
Implementation Method 4
the pump unit is designed for contactless magnetic bearing of the rotor and for contactless magnetic drive of the rotor by the stator
Data Source
Figure 1~2
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Figure 5~6
AI summary
A pump unit for a centrifugal pump is proposed, comprising the pump unit and a stator (100) extending in an axial direction (A) from a first axial end (110) to a second axial end (120), wherein a cup-shaped recess is provided at the first axial end (110) into which the pump unit (1) can be inserted, wherein the pump unit (1) has a pump housing (2) with an inlet (21) and an outlet (22) for a fluid to be pumped, and a rotor (10) arranged in the pump housing (2) with a plurality of vanes (103) for pumping the fluid, wherein the pump housing (2) defines a pump chamber (23), wherein the rotor (10) is rotatable about the axial direction (A), and wherein the pump unit (1) is designed for contactless magnetic bearing of the rotor (10) and for contactless magnetic drive of the rotor. (10) is designed by the stator (100),wherein the pump housing (2) comprises a cover part (4) and a base part (3), the base part (3) having a cylindrical cup (31) for receiving the rotor (10), which cup can be inserted into the cup-shaped recess of the stator (100), and wherein the outlet (22) has an inlet surface (221) through which the fluid can flow from the pump chamber (23) into the outlet (22). The inlet surface (221) of the outlet (22) has a profile which is not circular. Furthermore, a centrifugal pump for pumping a fluid is proposed, which comprises such a pump unit (1).