Turbine Scroll Vane Passages for Uniform Inward Gas Flow
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Solution Overview
Problem
Rotary internal combustion engines experience non-uniform gas flow into the turbine, leading to decreased turbine efficiency and structural fatigue due to periodic excitation forces.
Innovation Solution
A turbine scroll with a flow channel, stator vanes, and vane passages that direct gas flow in an inwardly spiraling direction, featuring a non-axisymmetric outer radial wall and uniformly configured stator vanes to enhance gas flow uniformity and maintain high tangential velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional scroll is used to organize combustion gases, then the gases can be directed into the turbine, but the gas flow exhibits circumferential and radial nonuniformities that decrease turbine efficiency and cause periodic excitation forces
Solution Approach 1:
The scroll is divided into multiple flow channels, each serving a specific rotary unit exhaust port. This segmentation allows independent optimization of gas flow paths, enabling better control over flow distribution and reducing nonuniformities that would otherwise decrease turbine efficiency and cause structural fatigue
Solution Approach 2:
Each flow channel is designed with specific geometric characteristics tailored to its position and the exhaust port it serves. The flow channels have varying cross-sectional areas and spiral configurations optimized for local flow conditions, ensuring uniform gas distribution across the turbine inlet while maintaining structural integrity
2Quantity of substance
If the flow channel cross-sectional area is increased to accommodate combustion gases, then more gas can be directed to the turbine, but the pulsation portion of the periodic flow increases
Solution Approach 1:
The scroll design incorporates flow channels with varying cross-sectional areas that work in conjunction with the periodic exhaust from rotary units. The varying area configuration is specifically designed to counterbalance the periodic nature of combustion gas generation, smoothing out pulsations while maintaining adequate gas quantity for turbine operation
Solution Approach 2:
The flow channel cross-sectional area is varied along the spiral path rather than remaining constant. This parameter change allows the scroll to accommodate the periodic flow characteristics of rotary engine exhaust, reducing pulsation effects while ensuring sufficient gas quantity reaches the turbine across different operating conditions
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
The solution increases turbine efficiency and reduces structural fatigue by attenuating gas flow pulsations, improving uniformity and maintaining high exit swirl, thereby enhancing the performance and durability of the turbine.
Implementation Method 1
The vane passages are configured to direct gas flow in an inwardly spiraling direction having a radially inward component and a circumferential component
Data Source
AI summary
A turbine scroll for use with an axial turbine is provided. The turbine scroll includes a flow channel, a scroll inlet, a plurality of stator vanes, and a plurality of vane passages. The flow channel is defined by an outer radial wall extending between first and second axial sidewalls that are spaced widthwise apart from one another. The stator vanes are disposed within the flow channel, spaced apart from one another, and are disposed around a circumference of the scroll. Each vane passage is defined between adjacent stator vanes. Each vane passage is open to an outer flow channel portion disposed radially between the stator vanes and the outer radial wall and is open to an annular region disposed radially inside of the stator vanes. The vane passages are configured to direct gas flow in an inwardly spiraling direction.