Hexagonal Jet Nozzles for Homogeneous Drying
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Solution Overview
Problem
Current drying technologies using impingement jets for organic electronics suffer from inhomogeneous heat and mass transfer coefficients, leading to surface unevenness and reduced performance, especially at low tape speeds and high flow velocities, which limits the applicability and quality of dried products.
Innovation Solution
A device with hexagonal impact jet nozzles and surrounding effusion openings arranged in a honeycomb structure, allowing for simultaneous suction and creating a homogeneous distribution of heat and mass transfer coefficients, minimizing interaction effects and wall jet regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If round nozzles are used in assembly line drying processes, then the drying speed can be increased, but inhomogeneity in the distribution of heat and mass transfer coefficients occurs in the direction of the belt and across the belt
Solution Approach 1:
The invention segments the circular flow field into multiple hexagonal jet nozzles arranged in a honeycomb pattern. Each hexagonal nozzle creates a localized flow pattern that, when combined with adjacent nozzles, forms a uniformly distributed flow field across the entire drying surface, eliminating the inhomogeneity caused by single round nozzles.
Solution Approach 2:
The hexagonal nozzle geometry creates locally optimized flow patterns at each nozzle position, while the honeycomb arrangement ensures that these local patterns combine to produce uniform global distribution. The effusion openings are strategically positioned to create local suction zones that further homogenize the flow field in specific regions.
2Productivity
If high flow velocities are used to increase drying efficiency, then productivity improves, but surface deformation of the product occurs due to impacting fluid jets
Solution Approach 1:
The total flow rate required for efficient drying is distributed across multiple hexagonal nozzles instead of concentrating it in fewer round nozzles. This segmentation reduces the velocity and impact force at each individual nozzle position, preventing surface deformation while maintaining overall drying efficiency through the combined effect of multiple nozzles.
Solution Approach 2:
The invention changes the geometric parameters of the nozzles from circular to hexagonal shape, and arranges them in a honeycomb pattern with specific spacing. This geometric transformation alters the flow distribution characteristics, reducing peak velocities and impact forces on the substrate surface while maintaining effective heat and mass transfer.
3Manufacturing precision
If slot nozzle systems are used to reduce inhomogeneity, then homogeneity improves compared to round nozzles, but gradient in the field of heat and material coefficients still occurs at the edges and in the direction of the belt
Solution Approach 1:
The invention uses hexagonal nozzles with asymmetric orientation (flat side facing the substrate) arranged in a honeycomb pattern. This asymmetric geometry and arrangement create more uniform flow distribution at the edges and across the belt direction compared to symmetric slot nozzles, reducing gradient effects while maintaining manufacturability.
4Ease of manufacture
If effusion openings are arranged with large spacing (six times the nozzle diameter), then manufacturing is simplified, but pronounced wall jet areas occur leading to extensive regions with relatively low heat transfer
Solution Approach 1:
The effusion openings are positioned at specific locations relative to each hexagonal nozzle, creating localized suction zones that control the flow pattern in the regions between nozzles. This local control prevents the formation of extensive wall jet areas with low heat transfer, ensuring uniform heat transfer coefficients even with simplified manufacturing spacing.
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 solution achieves a highly homogeneous distribution of heat and mass transfer coefficients, preventing unevenness on substrates and enabling efficient, gentle drying of sensitive thin layers, suitable for large-area organic electronics with improved performance and reduced surface deformation.
Implementation Method 1
effusion openings, through which the ejected fluid is suctioned off
Implementation Method 2
impact jet nozzles serve to ensure that a fluid for heat and mass transfer is jetted onto the substrate surface
Implementation Method 3
Impact jets are widely used in industrial production processes where workpieces have to be cooled, heated or dried. Although impinging jets are able to force convectively driven processes
Implementation Method 4
velocity measurements using magnetic resonance showed that the interaction of the jets with their neighbors can be minimized and unit cells can thus be created for a more homogeneous flow
Data Source
Figure 1a~2
Figure 3a~3b
AI summary
The invention relates to a device for transferring heat and mass, in particular for drying thin layers or coatings. The main focus of the invention is a jet array (3) with hexagonal jet nozzles (5) and the effusion openings (4) arranged around said nozzles. A particularly advantageous heat/mass transfer coefficient with excellent homogeneity is produced by the geometry of the spray and intake nozzles. Said device is therefore advantageous for drying sensitive components. The invention is additionally well-suited for deposition processes on surfaces. A drying hood that uses said device is also proposed. The invention further relates to a method for treating surface layers, in particular for gently drying organic (opto-)electronic components.