Multi-Phase Rotor With Stable Vapour Cavity for High-Speed Cavitation Control
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Solution Overview
Problem
Centrifugal pumps are susceptible to cavitation, which causes mechanical damage and negatively impacts performance due to phase changes from liquid to gas and back, limiting their operational range and acceleration energy.
Innovation Solution
A multi-phase rotor design with a disk body, inlet, liquid intake channel, and outlets that form a continuous stable vapour cavity above a threshold rotational speed, using inlet and outlet restrictions to maintain liquid seals and prevent ambient gas venting, allowing operation beyond cavitation thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If centrifugal pumps operate at high rotational speeds to increase acceleration energy, then productivity improves, but cavitation occurs causing mechanical damage and performance degradation
Solution Approach 1:
The patent converts the harmful cavitation phenomenon into a beneficial stable vapour cavity. By designing the rotor to maintain a controlled vapour cavity at high speeds, the harmful phase changes are eliminated while retaining the low-pressure environment, allowing the pump to operate beyond traditional cavitation thresholds without mechanical damage
Solution Approach 2:
The patent changes the operational parameters by maintaining a stable vapour cavity with controlled pressure and volume. The inlet and outlet restrictions are designed to maintain liquid seals that prevent ambient gas venting while allowing the vapour cavity to persist, enabling operation at rotational speeds that would traditionally cause damaging cavitation
2Reliability
If centrifugal pumps are designed to avoid cavitation by limiting operational parameters, then reliability improves, but the operational range and acceleration energy are restricted
Solution Approach 1:
The patent transitions from static cavitation avoidance to dynamic stable vapour cavity maintenance. The rotor is designed to rotate at high speeds while maintaining a stable vapour cavity through dynamically balanced liquid seals at the inlet and outlet restrictions, allowing the system to adapt to high-speed operation without compromising reliability
Solution Approach 2:
The patent controls the phase transition by maintaining a stable vapour cavity rather than allowing uncontrolled phase changes. The liquid seals prevent ambient gas from entering the cavity, ensuring that the vapour phase is maintained through controlled evaporation rather than damaging cavitation, expanding the operational range
3Stability of the object's composition
If inlet and outlet restrictions are added to maintain liquid seals, then device complexity increases, but stable vapour cavity formation is enabled
Solution Approach 1:
The patent merges the inlet and outlet restrictions into the rotor structure itself, integrating the liquid seal formation directly into the flow path. This integration reduces the need for separate sealing components while maintaining the stable vapour cavity, balancing complexity with performance
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
The design maintains a stable vapour cavity, preventing cavitation damage and enabling high-speed operation with consistent liquid flow, enhancing the rotor's lifespan and performance.
Implementation Method 1
a continuous stable vapour cavity is formed in the internal rotor cavity as the rotor rotates above a stable cavity threshold rotational speed
Implementation Method 2
As pressure drops to near or below the vapour-pressure point of a liquid, cavitation occurs where a change of state (phase change) from liquid to gas and then back to liquid occurs
Implementation Method 3
the inlet comprises an inlet restriction configured to constrain an inlet liquid mass at the inlet forming a liquid seal at the inlet as the rotor rotates about the axis of rotation
Implementation Method 4
the at least one outlet comprises an outlet restriction configured to retain an outlet liquid mass towards the outlet forming a liquid seal at the outlet as the rotor rotates about the axis of rotation
Data Source
AI summary
A multi-phase rotor comprising a disk body, an inlet to receive a liquid into the rotor, and at least one outlet configured to expel the liquid from the internal rotor cavity. A flow path is provided between the inlet and the at least one outlet by a liquid intake channel and internal rotor cavity. The rotor is configured to be rotatable about an axis of rotation and a continuous stable vapour cavity is formed in the internal rotor cavity as the rotor rotates above a stable cavity threshold rotational speed.