Duct Fin Structure with Vortex Generation to Suppress Flow Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing duct structures face challenges in suppressing flow separation while minimizing pressure drop, particularly at inlets and curved portions, where flow disturbances occur, leading to inefficiencies in fluid flow and engine performance.
Innovation Solution
The duct structure incorporates a fin that rises from the inner surface, ends within the fluid passage, and features a downstream end surface designed to generate a vortex, which redirects fluid flow, thereby suppressing flow separation and reducing pressure drop. The fin is integral with the duct, reducing parts and manufacturing steps, and is optimized in height and inclination to minimize cross-sectional area reduction and flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flow control plate is provided extending over the entire cross-section of the duct inlet, then flow separation is suppressed, but pressure drop becomes considerably large
Solution Approach 1:
The flow control plate is segmented into multiple fins that extend only partially across the duct cross-section. Each fin is spaced apart from others, creating gaps that allow fluid to pass through. This segmentation maintains flow separation suppression by disrupting separated flow regions while reducing pressure drop by allowing continued fluid passage through the gaps between fins.
Solution Approach 2:
Instead of providing a complete flow control plate across the entire cross-section, the invention uses partial action by implementing individual fins that cover only portions of the cross-section. The fins are positioned and dimensioned to provide sufficient flow control effect while leaving adequate open area for fluid passage, thus achieving flow separation suppression with minimal pressure drop penalty.
2Reliability
If the fin extends over the entire cross-section of the duct, then flow separation is suppressed, but the pressure drop caused by the fin increases
Solution Approach 1:
The fins are designed with local quality by positioning them specifically at locations where flow separation is most likely to occur, such as at the inlet and along curved portions of the duct. The fins extend only to the height necessary to control flow separation at these critical locations, rather than extending across the entire duct height, thus providing effective flow control while minimizing pressure drop.
Solution Approach 2:
The continuous flow control plate is segmented into discrete fins with gaps between them. This segmentation allows the fins to provide flow separation control at critical locations while the gaps between fins allow fluid to pass through with minimal resistance, thereby reducing the overall pressure drop compared to a solid plate extending across the entire cross-section.
3Reliability
If a flow control structure is added to suppress flow separation, then flow attachment is improved, but device complexity increases
Solution Approach 1:
The fins are merged with the duct structure by forming them as integral parts of the duct, either as protrusions from the inner surface or as embedded structures within the duct wall. This merging eliminates the need for separate attachable flow control components, reducing assembly complexity while maintaining flow separation suppression functionality.
Solution Approach 2:
The fins serve multiple functions: they suppress flow separation, control flow direction, and can be designed to accommodate manufacturing processes. By integrating flow control functionality directly into the duct structure, the design achieves multi-functionality without adding separate components, thereby reducing overall device 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 design effectively suppresses flow separation and decreases pressure drop, improving engine output by ensuring fluid flow continuity and reducing energy loss, while maintaining a minimal impact on the duct's cross-sectional area and manufacturing complexity.
Implementation Method 1
the fin includes the downstream end surface having the form obtained when cutting off a downstream end portion of the fin. A vortex is intentionally generated in the downstream of the downstream end surface of the fin. Since a pressure in the vortex is lower than a pressure in a surrounding portion of the vortex, the vortex can draw a fluid portion having flowed along a top surface of the fin and then flowing downstream of the downstream end surface of the fin to the vortex
Data Source
AI summary
A duct structure including a fin having a downstream end surface extending between an inner surface of a duct and a downstream end of a top surface of the fin in a height direction of the fin. As a result, a vortex can be intentionally generated in a downstream of the downstream end surface of the fin. Since a pressure in the vortex is lower than a pressure in a surrounding portion of the vortex, the vortex can draw a fluid flow having flowed along the top surface of the fin to the vortex and can change the flow to a flow flowing along a portion of the inner surface of the duct located downstream of the fin. As a result, a flow separation from the inner surface of the duct can be suppressed.