Turbine Diffuser Projections for Flow Separation
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Solution Overview
Problem
Existing turbine designs face efficiency losses at different operating points due to the placement of stator vanes, which can increase costs and reduce productivity, and require improved diffuser shapes to enhance turbine rotor blade performance across varying flow rates.
Innovation Solution
A turbine with a rotatable impeller and a tubular diffuser featuring radially inward projections near the inlet end, arranged to cause flow separation and increase flow velocity between rotor blades, enhancing static pressure differences and torque application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a stator vane is disposed downstream of a turbine rotor blade, then turbine efficiency is improved at one operating point, but a loss occurs at another operating point and productivity deteriorates
Solution Approach 1:
The patent applies local quality by forming projections only at specific positions on the diffuser wall rather than using a complete stator vane structure. The projections are located at the inlet end of the diffuser where flow separation occurs, creating localized flow control that improves efficiency without the complexity and productivity loss of full stator vane implementation.
2Loss of energy
If a stator vane is disposed downstream of a turbine rotor blade, then turbine efficiency is improved at one operating point, but device complexity increases
Solution Approach 1:
The patent replaces the complex stator vane structure with simple projections formed directly on the diffuser wall. This localized approach achieves flow control functionality with minimal additional structural complexity, avoiding the need for separate stator vane components and their associated mounting and adjustment mechanisms.
Solution Approach 2:
The patent merges the flow control function with the existing diffuser structure by forming projections on the diffuser wall. This integration eliminates the need for separate stator vane components, reducing device complexity while maintaining the ability to control fluid flow and improve turbine efficiency.
3Loss of energy
If the diffuser shape is modified to improve turbine rotor blade performance, then turbine performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent modifies the diffuser shape locally by adding projections at specific positions rather than redesigning the entire diffuser geometry. This localized modification approach maintains ease of manufacture by requiring changes only in specific regions of the diffuser, allowing the majority of the diffuser structure to remain simple and easy to fabricate.
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 design improves turbine performance by increasing flow velocity and static pressure differences, reducing losses and enhancing torque, while maintaining efficiency across different operating points without increasing costs or complexity.
Implementation Method 1
since the plurality of projections projecting radially inward of the tubular member are formed, flow separation is caused between the adjacent projections, and with the separation, the fluid flow close to the shroud side shifts radially inward as a whole
Implementation Method 2
the flow velocity difference of a fluid between the inlet and the outlet of the rotor blade increases, that is, the static pressure difference between the inlet and the outlet of the rotor blade increases, and the torque applied to the blade surface of the rotor blade increases
Data Source
AI summary
A turbine includes: a rotatable impeller with a hub provided with a plurality of rotor blades; and a tubular member in which a diffuser located downstream of the impeller is formed. On an inner surface of the tubular member, a plurality of projections projecting radially inward of the tubular member are formed at positions closer to an inlet end of the tubular member than an outlet end of the tubular member. The plurality of projections are arranged in a circumferential direction of the inner surface so as to leave a space between adjacent projections.