Cavitation Peening Nozzle for Smoothing Tubular Interior Surfaces
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Solution Overview
Problem
Current methods for additive manufacturing fail to effectively smooth the rough surfaces of complex components due to the infeasibility of generating abrasive cavitation bubble clouds proximate to interior surfaces.
Innovation Solution
A system and method involving a cavitation peening nozzle and a spacing device to generate cavitation bubbles and energize abrasive particles within a tubular workpiece, using a cavitating jet to smooth interior surfaces by maintaining a radial space and creating a suction action for abrasive flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cavitation peening nozzle is inserted into a cavity to generate cavitation bubbles, then interior surfaces can be smoothed, but it is difficult to generate abrasive cavitation bubble clouds in sufficient proximity to surfaces interior to channels
Solution Approach 1:
The patent introduces a fluid suction passage as an intermediary element that communicates with the fluid supply passage. The suction passage creates a suction cavitation flow that acts as a mediator to transport abrasive particles to the cavitation bubble cloud, enabling the abrasive material to reach interior surfaces that would otherwise be inaccessible to direct cavitation generation
Solution Approach 2:
The patent utilizes hydraulic principles by employing fluid suction and pressure differential mechanisms. The suction pump creates negative pressure to draw fluid and abrasive particles through the suction passage, while the narrowed portion creates positive pressure to generate cavitation bubbles, effectively using hydraulic forces to deliver abrasive material to interior surfaces
2Adaptability or versatility
If traditional manufacturing methods are used, then surface finish quality is good, but complex shapes and features are not practical or feasible to manufacture
Solution Approach 1:
The patent replaces traditional mechanical contact-based surface finishing methods with cavitation-based mechanical action. The collapsing cavitation bubbles generate micro-jets that impact the surface with high pressure, achieving surface smoothing without requiring physical contact tools that would be unable to access complex interior geometries
Solution Approach 2:
The patent exploits the phase transition of water from liquid to gas (cavitation) and back to liquid (collapse). This phase change creates concentrated energy release in the form of collapsing bubbles that can smooth surfaces in locations inaccessible to conventional mechanical tools, thereby enabling high surface quality on complex geometries
3Manufacturing precision
If a narrowed portion is provided in the fluid supply passage, then sucking cavitation flow is generated, but the device complexity increases
Solution Approach 1:
The patent merges the fluid supply passage and fluid suction passage into a single integrated nozzle structure. The narrowed portion serves dual functions: generating cavitation bubbles through pressure differential and creating suction flow to transport abrasive particles. This merging reduces the number of separate components while achieving multiple functions
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
Effectively smooths and peens interior surfaces, improving surface finish and residual stress while using safe and inexpensive materials like water and ceramic abrasives, suitable for complex geometries.
Implementation Method 1
Cavitation bubbles are formed in a fluid by a transition to gas phase resulting from an increase in flow velocity and internal energy, then a collapse implosion as the flow velocity and pressure surrounding the bubbles dissipates. When a cavitation bubble collapses, a micro-jet is produced that can energize particles of an abrasive material.
Implementation Method 2
the pressure of the cavitating jet down the tubular section results in a suction action which draws the mixture of the liquid and the abrasive into and down the tubular section past the cavitation peening nozzle
Data Source
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AI summary
A method (300) of smoothing an inner surface of a tubular wall (232, 262, 264) of a workpiece (136, 224, 236, 260) is disclosed, including immersing (310) the workpiece in a mixture of a liquid and an abrasive and inserting (312) a cavitation peening nozzle (142, 212) into a cavity of the workpiece. The method further includes injecting (314) a cavitating jet from the cavitation peening nozzle into the cavity.