Hydrofoil Stripe Structure for Suppressing Cloud Cavitation

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Solution Overview

Problem

Uncontrolled cloud cavitation in hydraulic machinery leads to vibration, noise, and cavitation erosion, reducing efficiency and service life, and existing active cavitating flow control structures require external energy.

Innovation Solution

A hydrofoil cavitating flow control structure with primary and secondary protuberant stripes on the suction side, altering the reentrant jet direction and reducing momentum strength to suppress cloud cavitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If active cavitating flow control structure is used, then cavitating flow control effect is achieved, but external energy supply is required and device complexity increases

Engineering Contradiction:

Improvecavitating flow control effectVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs passive control structures (protuberant stripes) that automatically control cavitation flow without requiring external energy supply or active control systems. The structures utilize the natural flow field characteristics to generate the desired control effect, making the system self-sufficient and eliminating complex energy supply requirements.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent extracts and eliminates the need for active control systems, sensors, and external energy supply mechanisms by using simple passive geometric structures (protuberant stripes) that inherently control cavitation through their shape and position, thereby reducing device complexity while maintaining control effectiveness.

Inventive Principle:

Principle #2Taking out (Extraction)

2Productivity

If cloud cavitation shedding occurs, then hydrodynamic performance deteriorates, but cavitation erosion and pressure pulsation increase

Engineering Contradiction:

Improvehydrodynamic performanceVSAvoidcavitation erosion

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The protuberant stripes are positioned upstream in the cavitation development region to preemptively control the flow field and prevent the formation and shedding of cloud cavitation. By acting before cavitation shedding occurs, the structures eliminate the harmful effects of cavitation erosion and pressure pulsation while maintaining hydrodynamic performance.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent applies localized geometric modifications (protuberant stripes) at specific positions on the hydrofoil surface where cavitation initiates and develops. These localized structures create favorable flow conditions in the critical regions, controlling cavitation behavior without affecting the overall hydrofoil performance and preventing localized cavitation erosion.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If passive control structure is used, then no external energy supply is needed and ease of operation improves, but control effectiveness may be reduced

Engineering Contradiction:

Improveease of operationVSAvoidcontrol effectiveness

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent optimizes key geometric parameters of the passive control structures, including the height, length, spacing, and angle of the protuberant stripes. By carefully selecting these parameters within specific ranges, the structures achieve effective cavitation control while maintaining the simplicity and ease of operation characteristic of passive systems, without sacrificing control effectiveness.

Inventive Principle:

Principle #35Parameter changes

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

Significantly reduces cloud cavitation shedding, pressure pulsation, and cavitation erosion, enhancing hydrodynamic performance and efficiency.

Implementation Method 1

Cavitation is a complex phase change phenomenon, which usually appears when a local static pressure in a liquid is lower than a saturated vapor pressure

Methodology Applied

Scientific EffectCavitation: Cavitation

Implementation Method 2

the primary protuberant stripe and the second protuberant stripes on the suction side of the hydrofoil can change a movement direction of the reentrant jet and weaken a momentum strength of the reentrant jet

Methodology Applied

Scientific EffectHydrodynamic flow control:

Data Source

PatentUS12485999B2Hydrofoil cavitating flow control structure

Publication Date: 2025.12.02 WUHAN UNIV

AI summary

A hydrofoil cavitating flow control structure includes a hydrofoil. A primary protuberant stripe is disposed in a middle position of a suction side of the hydrofoil, a plurality of symmetrically-distributed secondary protuberant stripes are disposed obliquely at both sides of the primary protuberant stripe, and the plurality of secondary protuberant stripes are uniformly and equidistantly distributed along the length direction of the primary protuberant stripe. By changing geometric parameters such as an included angle between the primary protuberant stripe and the second protuberant stripe, a ratio of cross section diameters and a distribution spacing of the second protuberant stripes along a chord length direction of the hydrofoil and the like, the shedding of cloud cavitation on a hydrofoil surface is effectively suppressed, and cavitation erosion and pressure pulsation generated by cavitation collapse is reduced, thus improving the operation efficiency and the service life of hydraulic machinery.