Exhaust Diffuser Struts with Varying Airfoil Angles
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Solution Overview
Problem
Conventional exhaust diffusers in torque-generating turbines face inefficiencies due to flow separation and high drag at varying flow angles, leading to reduced pressure recovery and potential blockages.
Innovation Solution
The design incorporates supporting struts with sections having different airfoil shapes and angles of incidence, allowing for a higher range of angle of attack, reducing drag, and enhancing pressure recovery by adapting to changing flow angles through strategically placed twin-struts and varying airfoil thickness and camber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional supporting struts with uniform airfoil shapes are used in exhaust diffusers, then manufacturing is simplified, but flow separation and high drag occur at varying flow angles leading to reduced pressure recovery
Solution Approach 1:
The patent applies local quality by varying the airfoil shape parameters (thickness, camber, leading edge radius) at different radial positions along the supporting strut. The root section has different geometry than the tip section, with each location optimized for the local flow conditions. This allows the strut to adapt to varying flow angles throughout its length, reducing flow separation and drag while improving pressure recovery without requiring complete redesign of the entire strut assembly
Solution Approach 2:
The patent implements dynamics by designing the strut with continuously varying airfoil parameters along its span rather than uniform sections. The thickness ratio, camber, and leading edge radius change progressively from root to tip, creating a dynamic adaptation to the changing flow field. This gradient design allows the strut to maintain optimal aerodynamic performance across the entire range of flow angles encountered in the exhaust diffuser
2Loss of energy
If fewer supporting struts are used to reduce drag, then pressure recovery improves, but structural stability may be compromised
Solution Approach 1:
The patent applies parameter changes by modifying the airfoil geometry parameters (thickness ratio, camber, leading edge radius) along the strut length to optimize the balance between drag reduction and structural stability. The root section maintains greater thickness for structural support, while the tip section uses thinner, more aerodynamic profiles. This progressive parameter variation allows reduction in overall strut drag while preserving necessary structural integrity at critical locations
3Ease of manufacture
If struts with prismatic design are used, then manufacturing is easier, but they generate high drag and cause flow separation at varying flow angles
Solution Approach 1:
The patent applies local quality by implementing different airfoil cross-sections at different locations along the strut length. The root section has different thickness and camber characteristics than the intermediate and tip sections. This localized variation in geometry allows each section to be optimized for its specific position in the flow field, reducing overall drag and preventing flow separation while remaining manufacturable through standard aerospace fabrication techniques
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 improves pressure recovery and reduces drag, preventing flow separation and blockages, thereby increasing the efficiency of the exhaust diffuser and maintaining structural stability with fewer struts.
Implementation Method 1
The supporting strut comprises a middle section having a first airfoil and an outer section having a second airfoil, the second airfoil having a higher angle of incidence than the first airfoil
Implementation Method 2
This design improves pressure recovery and reduces drag, preventing flow separation and blockages
Implementation Method 3
an exhaust diffuser to slow down the fluid flow and thereby enhance pressure recovery
Implementation Method 4
exhaust diffuser for a torque-generating turbine
Data Source
AI summary
An exhaust diffuser and method for manufacturing an exhaust diffuser is provided. An exhaust diffuser for a torque-generating turbine, in particular a torque-generating gas turbine is provided, the exhaust diffuser having an inner member, and the inner member having an outer surface. The outer member having an inner surface, and the inner member and the outer member forming an annular channel at least a first supporting strut connecting the inner member and the outer member, the supporting strut extending essentially radially from the inner surface to the outer surface, the supporting strut having a middle section, the middle section having a first airfoil and an outer section having a second airfoil, and the second airfoil having a higher angle of incidence than the first airfoil. Furthermore, it is described a method for manufacturing an exhaust diffuser.