PTC Electric Heater Surface Structure to Disrupt Laminar Flow
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Solution Overview
Problem
Existing electric heating devices with PTC elements face inefficiencies due to poor heat conduction, leading to suboptimal performance, especially in motor vehicle applications, where self-regulating properties are crucial but require effective heat dissipation.
Innovation Solution
The introduction of a three-dimensional surface structure on the heat-emitting surfaces, achieved through mechanical finishing or thermoforming, disrupts laminar flow, enhancing heat transfer coefficients by creating micro swirling or turbulence, thereby improving heat exchange between the PTC element and the fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth heat-emitting surface is used, then the device structure is simple and easy to manufacture, but the heat transfer coefficient is low due to laminar boundary layer formation
Solution Approach 1:
The patent transforms the two-dimensional smooth surface into a three-dimensional structured surface by adding surface protrusions and grooves. This dimensional change disrupts the laminar boundary layer and enhances heat transfer while maintaining manufacturing feasibility through techniques like injection molding or thermal spraying.
Solution Approach 2:
The patent creates a porous or structured surface layer on the heat-emitting surface using materials with specific surface properties. This porous structure increases surface area and disrupts laminar flow, improving heat transfer coefficient without significantly complicating the manufacturing process.
2Loss of energy
If a three-dimensional surface structure is introduced to enhance heat transfer, then the heat transfer coefficient increases by at least 150%, but the manufacturing complexity increases
Solution Approach 1:
The patent integrates the heat transfer enhancement function directly into the housing structure itself, making the housing serve dual purposes: structural support and heat transfer optimization. This eliminates the need for separate heat transfer enhancement components, reducing overall device complexity.
Solution Approach 2:
The patent combines the housing structure with the heat transfer enhancement features by integrating the three-dimensional surface structure directly onto the heat-emitting surfaces. This merging of functions reduces the number of separate components and simplifies the overall device architecture.
3Power
If the PTC element operates at higher temperature to increase heat output, then more heat is generated, but the efficiency decreases due to poor heat conduction to the fluid
Solution Approach 1:
The patent applies local quality enhancement by creating three-dimensional surface structures specifically on the heat-emitting surfaces that are in direct contact with the fluid. This localized modification improves heat conduction at the critical interface between the PTC element and the fluid, ensuring efficient heat transfer where it is most needed without affecting other parts of the device.
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 increases the heat transfer coefficient by at least 150% and allows the PTC element to operate more effectively, transferring 3-5% more heat to the medium while maintaining efficient cooling, thus enhancing the overall efficiency of the heating device.
Implementation Method 1
The introduction of a three-dimensional surface structure on the heat-emitting surfaces, achieved through mechanical finishing or thermoforming, disrupts laminar flow, enhancing heat transfer coefficients by creating micro swirling or turbulence
Implementation Method 2
enhancing heat transfer coefficients by creating micro swirling or turbulence, thereby improving heat exchange between the PTC element and the fluid
Implementation Method 3
at least one electric heating assembly (22) that is heat-conductively coupled to a heat emitting surface (73) delimiting the circulation chamber (14)
Implementation Method 4
heat-conductively coupled to a heat emitting surface
Data Source
AI summary
An electric heating device has a housing with inlet and outlet openings for a fluid to be heated. The housing has a circulation chamber for passing the fluid to be heated through the housing and a connection chamber for the electrical connection of at least one PTC heating assembly. The PTC heating assembly comprises at least one PTC element strip conductors which energize the PTC element with different polarity and which are heat-conductively coupled to at least one surface of the housing delimiting the circulation chamber. Measures are taken to disturb a laminar boundary layer of the fluid to be heated on at least one of the heat-emitting surfaces. A method is provided for processing at least one heat-emitting surface formed by the housing to provide a structure that disturbs the laminar boundary layer of the fluid to be heated.