Vortex Restart Structure for Turbulated Heat Exchanger Passages
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Solution Overview
Problem
In cast heat exchangers, counter-rotating vortex pairs break down and merge, leading to reduced heat transfer due to asymmetric passage geometry, resulting in a significant reduction in overall heat transfer efficiency.
Innovation Solution
The implementation of a vortex restart structure with splash ribs extending from the parting surfaces into the flow passage beyond the turbulators, spaced appropriately to prevent vortex breakdown and reassert influence on the fluid flow, reforming counter-rotating vortex pairs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If chevron style turbulators are used to generate counter-rotating vortex pairs, then heat transfer is enhanced, but the vortices break down and merge in asymmetric passages, reducing heat transfer efficiency
Solution Approach 1:
The passage is segmented into multiple sections with turbulators placed at specific intervals. The asymmetric passage is divided such that turbulators are positioned to create symmetric vortex generation zones, preventing vortex breakdown and merge by breaking the continuous asymmetric flow path into manageable segments that maintain vortex integrity
Solution Approach 2:
The invention intentionally introduces asymmetric features (turbulators) into the asymmetric passage to counteract the natural asymmetric flow patterns. By placing turbulators at specific locations and angles, the design creates localized symmetric vortex pairs that prevent the natural vortex breakdown and merge that would occur in the asymmetric passage geometry
2Productivity
If vortex breakdown and merge occurs, then a single larger vortex forms transporting spent fluid around the passage, but this reduces temperature differential and significantly reduces overall heat transfer
Solution Approach 1:
Turbulators are positioned upstream to pre-condition the flow and generate counter-rotating vortex pairs before the flow becomes asymmetric. This preliminary vortex generation occurs in a controlled zone where the turbulators can symmetrically initiate vortices that remain stable throughout the passage, preventing downstream vortex breakdown and maintaining temperature differential
Solution Approach 2:
The turbulators are designed with specific local characteristics (height, angle, spacing) that are optimized for their position in the asymmetric passage. Each turbulator section has tailored geometry to generate vortices of appropriate strength and orientation locally, ensuring that vortex pairs form and maintain stability in each local zone rather than breaking down globally
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 heat transfer by maintaining a higher temperature differential between the fluid and the wall, achieving a 10% higher integrated heat flux with minimal increase in pressure loss.
Implementation Method 1
a set of counter-rotating vortex pairs V is produced
Implementation Method 2
enhance the convection heat transfer coefficient
Implementation Method 3
thermal energy is extracted from Fluid A, via convection, conducted through the parting surface of the heat exchanger and transferred to Fluid B, also via convection
Implementation Method 4
conducted through the parting surface of the heat exchanger
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A vortex restart structure (110) including a flow passage having a first wall and a second wall opposite the first wall (114), each of the first wall and the second wall including a parting surface; multiple flow turbulators (122) extending from at least one parting surface of the first wall or the second wall; and at least one splash rib (128) extending from at least one parting surface of the first wall or the second wall, wherein the at least one splash rib (128) extends from the parting surface into the flow passage beyond the multiple flow turbulators (122).