Turbine Branching Portion Area Optimization
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Solution Overview
Problem
In turbines with bypass flow passages, flow separation at the branching portion between the exhaust flow passage and the bypass flow passage leads to increased pressure loss, reducing turbine efficiency.
Innovation Solution
The turbine design includes an exhaust flow passage with a branching portion having a flow passage sectional area of 0.6 times or more than the exhaust-air introduction port, and a gradual decrease in sectional area ratio towards the downstream side to minimize flow separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bypass flow passage is introduced to allow communication between exhaust flow passage and discharge flow passage, then the turbine can provide alternative flow paths, but flow separation occurs at the branching portion increasing pressure loss and reducing turbine efficiency
Solution Approach 1:
The patent applies parameter changes by optimizing the sectional area of the branching portion. Specifically, the branching portion is designed with a sectional area that is 0.6 times or more of the exhaust-air introduction port sectional area, and the exhaust flow passage sectional area is designed to be 0.9 times or more of the exhaust-air introduction port sectional area in the region 60% or more on the exhaust-air introduction port side. This parameter optimization reduces flow separation and minimizes pressure loss while maintaining the bypass flow passage functionality.
2Volume of moving object
If the branching portion has a small flow passage sectional area, then the turbine structure is more compact, but flow separation increases causing higher pressure loss and lower efficiency
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges for the branching portion sectional area. The branching portion is designed with a sectional area of 0.6 times or more of the exhaust-air introduction port, which balances compactness with sufficient flow capacity to prevent separation. This parameter optimization allows the turbine to maintain a compact structure while achieving at least 0.8% efficiency improvement.
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 turbine efficiency by reducing pressure loss through the suppression of flow separation and vortex formation at the branching portion, achieving an efficiency improvement of at least 0.8% when the sectional area ratio is 0.6 or more.
Implementation Method 1
in a branching portion between the exhaust flow passage and the bypass flow passage, separation of flow of gas is liable to occur. The separation of flow of gas in the branching portion increases pressure loss in the turbine
Data Source
AI summary
Provided is a turbine, including: an accommodating portion configured to accommodate a turbine impeller; an exhaust flow passage configured to allow communication between the accommodating portion and an exhaust-air introduction port; a discharge flow passage configured to allow communication between the accommodating portion and an exhaust-air discharge port; a bypass flow passage configured to allow communication between the exhaust flow passage and the discharge flow passage while detouring the accommodating portion; and a branching portion between the exhaust flow passage and the bypass flow passage. The branching portion has a flow passage sectional area of 0.6 times or more a flow passage sectional area of the exhaust-air introduction port.