Cold Spray Nozzle With Segmented Particulate Conduit
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Solution Overview
Problem
Conventional cold spray nozzles face limitations in achieving high particulate velocities and maintaining nozzle integrity due to temperature and fouling issues, which affect the quality of deposition and the operational range of the system.
Innovation Solution
The design includes a particulate conduit with a uniform flow area within both converging and diverging segments, separated from the motive gas flow, and an insert that fixes the conduit within the axial bore, allowing for higher gas temperatures and velocities while preventing intermixing of gases and reducing fouling by separating the particulate from nozzle surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cold spray nozzles are used to accelerate solid particulate, then particulate velocities can be achieved, but temperature reduction and pressure reduction limit the operational temperature range and deposition quality
Solution Approach 1:
The nozzle is divided into two separate flow paths: a central particulate conduit for carrying solid particulate and an annular passage for motive gas flow. This segmentation allows independent optimization of temperature and velocity parameters for each flow, enabling higher gas temperatures without compromising particulate delivery reliability
Solution Approach 2:
The particulate conduit acts as an intermediary structure that separates the particulate flow from the high-temperature motive gas flow. This intermediary allows the motive gas to be heated to higher temperatures while the particulate remains protected, extending the operational temperature range
2Speed
If motive gas flows are intermixed in conventional nozzles, then gas acceleration can occur, but fouling of nozzle surfaces reduces operational efficiency and deposition quality
Solution Approach 1:
The nozzle flow path is segmented into a central particulate conduit and an outer annular motive gas passage, physically separating the two flows. This prevents fouling materials from contaminating the particulate stream while maintaining effective gas acceleration and velocity generation
Solution Approach 2:
The particulate flow is extracted from the main motive gas flow by directing it through a separate central conduit. This extraction removes the particulate from potential fouling zones while maintaining the accelerating effect of the motive gas in the annular passage
3Speed
If higher gas temperatures are used to increase particulate velocities, then deposition quality improves, but conventional nozzle materials cannot withstand the temperatures
Solution Approach 1:
The nozzle structure is segmented into a central particulate conduit that is thermally isolated from the high-temperature annular motive gas flow. This allows the outer nozzle body to withstand high gas temperatures while the inner particulate conduit maintains structural integrity at lower temperatures
Solution Approach 2:
The particulate conduit serves as a thermal intermediary, protecting the nozzle structure from direct exposure to high-temperature motive gas. This intermediary structure enables higher operating temperatures that increase particulate velocity without compromising nozzle material strength
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 configuration enables higher solid particulate velocities and prevents fouling, allowing for improved deposition quality and operation at higher temperatures, exceeding conventional limits, and extends the nozzle's operational range.
Implementation Method 1
The gas undergoes a temperature reduction and pressure reduction while increasing velocity at it traverses the nozzle
Implementation Method 2
This accelerates the entrained particulate to velocities sufficient to induce plastic deformation
Implementation Method 3
the particulate conduit limits (or eliminates) heat transfer between the second motive gas flow and the solid particulate
Implementation Method 4
the solid particles undergo plastic deformation. The deformation disrupts the thin, oxide surfaces and films of the solid particles and/or workpiece surface to achieve conformal contact
Implementation Method 5
Conformal contact of the solid particles in conjunction with the impact contact pressure impact promotes solid-state bonding of the solid particles and workpiece surface
Data Source
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AI summary
A nozzle assembly (100) for a cold spray deposition system (10) includes a nozzle body (102) with an axial bore. The axial bore defines a converging segment (112), a diverging segment (116) downstream of the converging segment (112), and a throat (114) fluidly connected between the converging and diverging segments (112, 116) of the axial bore. A particulate conduit (108) is fixed within the axial bore and extends along the axial bore diverging segment (116) for issuing solid particulate into the diverging segment (116) of the axial bore .