Wire Arc Spraying with Streamlined Wire Geometry for Better Deposition
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Solution Overview
Problem
Conventional wire arc spraying experiences significant vortex shedding and oxidation of molten particles, leading to reduced deposition efficiency, uneven atomization, and poor adhesion of the spray coating due to Karman vortex streets, resulting in environmental and economic inefficiencies.
Innovation Solution
The device and method employ streamlined contact tubes and metal wires with aligned cross-sections to minimize flow resistance and vortex formation, ensuring precise alignment of the metal wires with the atomizing gas flow, thereby improving the discharge pattern and adhesion of molten droplets onto the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional round metal wires and contact tubes are used in wire arc spraying, then the device structure is simple and easy to manufacture, but vortex shedding occurs at the wire cross-sections leading to Karman vortex streets, causing significant particle divergence, oxidation, and reduced deposition efficiency
Solution Approach 1:
The patent applies streamlined cross-sectional geometry to both the contact tube and metal wire, replacing conventional round cross-sections with aerodynamically optimized shapes that reduce flow resistance and prevent vortex formation. The streamlined cross-section features curved surfaces that guide the atomizing gas flow smoothly around the wire, eliminating the Karman vortex street phenomenon and improving particle trajectory control.
Solution Approach 2:
The patent changes the geometric parameters of the contact tube and wire cross-sections from circular to streamlined shapes. This parameter change optimizes the flow characteristics of the atomizing gas, reducing turbulence and vortex shedding. The streamlined geometry modifies the flow field around the wire, preventing particle divergence and oxidation while maintaining efficient material transfer to the substrate.
2Reliability
If streamlined contact tubes and wires are used to reduce vortex shedding, then deposition efficiency and adhesion improve, but the manufacturing complexity and precision requirements increase
Solution Approach 1:
The streamlined cross-sectional geometry with curved surfaces improves spray coating adhesion and quality by eliminating vortex-induced particle divergence and oxidation. The aerodynamically optimized shape ensures smooth gas flow and consistent particle delivery to the substrate, resulting in more reliable and high-quality coatings.
Solution Approach 2:
Changing the cross-sectional geometry parameters from circular to streamlined shapes enhances coating reliability by controlling the atomizing gas flow more effectively. This parameter change reduces turbulence and ensures consistent particle delivery, improving adhesion and coating quality despite increased manufacturing precision requirements.
3Manufacturing precision
If conventional wire arc spraying is used, then the process is simple to operate, but particle oxidation and uneven atomization occur due to vortex regions, reducing coating quality
Solution Approach 1:
The streamlined cross-sectional geometry of the contact tube and wire improves atomization uniformity by eliminating vortex regions. The aerodynamically optimized shape ensures smooth, laminar gas flow around the wire, preventing turbulence and ensuring consistent particle delivery. This results in more uniform atomization and higher coating quality.
Solution Approach 2:
Modifying the cross-sectional geometry parameters to streamlined shapes enhances atomization uniformity by controlling the gas flow field more effectively. This parameter change eliminates vortex-induced turbulence, ensuring consistent particle velocity and distribution, thereby improving coating quality and reducing oxidation.
4Productivity
If round cross-section metal wires are used, then flow resistance to atomizing gas is high causing Karman vortex streets and particle divergence, but streamlined cross-section wires increase manufacturing complexity
Solution Approach 1:
The streamlined cross-sectional geometry of the metal wire reduces flow resistance to the atomizing gas by providing smooth, curved surfaces that guide flow around the wire. This eliminates Karman vortex streets and prevents particle divergence, improving material utilization and deposition efficiency by ensuring more particles reach the substrate.
Solution Approach 2:
Changing the wire cross-sectional geometry from circular to streamlined shapes optimizes the flow field around the wire, reducing turbulence and vortex formation. This parameter change improves particle trajectory control and deposition efficiency, ensuring better material utilization despite increased geometric complexity.
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 approach enhances deposition efficiency by reducing vortex-induced oxidation and divergence, resulting in improved adhesion and reduced porosity of the spray coating, thus increasing the economic viability and quality of the coating process.
Implementation Method 1
an arc is ignited, which serves as the energy source for melting the wire filler material. Temperatures exceeding 5000 K are reached in the arc
Implementation Method 2
an electric arc is generated between the at least one first wire and the at least one counter electrode or between at least one first and second wire
Implementation Method 3
A gas stream (compressed air or a technical gas) detaches the molten material from the wire ends and accelerates it as a particle stream onto the component to be coated
Implementation Method 4
The outer surface of the at least one first contact tube has a streamlined cross-section and/or the cross-sectional areas of the inner channel of the at least one first contact tube are at least partially adapted to the streamlined cross-section of the supplied first metal wire
Implementation Method 5
A major problem in wire arc spraying is vortex shedding of the atomizing gas flow at or behind the wire cross-sections. These vortex regions circulate continuously in the so-called dead zones of the wires
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Arc wire torch (2) and method for thermal coating of surfaces using a wire arc, with a metal wire (3) having a streamlined cross-section.