Mixed Flow Turbine Intermediate Blades Reduce Inertia
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional mixed flow turbines face inefficiencies due to a low number of blades, which hinders the efficient conversion of high-velocity flows to torque, leading to reduced efficiency and transient response, while increasing the number of blades to address this issue often results in increased moment of inertia.
Innovation Solution
The introduction of intermediate blades with an intermediate height between main blades in a mixed flow turbine, forming a hub-side impulse blade portion and a shroud-side reaction blade portion, allowing for increased blade count without raising the moment of inertia, thereby enhancing the impulse blade characteristic and improving efficiency and transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of blades is increased to improve efficiency, then the efficiency is improved, but the moment of inertia increases, resulting in decreased rotational acceleration
Solution Approach 1:
The turbine rotor blade is segmented into two distinct functional portions: a hub-side impulse blade portion and a shroud-side reaction blade portion. This segmentation allows each portion to perform its specialized function independently, enabling the turbine to achieve high efficiency without requiring a large number of blades throughout the entire radius, thus avoiding excessive moment of inertia.
Solution Approach 2:
Different portions of the turbine rotor blade are given different local qualities and functions. The hub-side portion is designed with impulse blade characteristics (optimized for high-velocity flow conversion), while the shroud-side portion is designed with reaction blade characteristics (optimized for torque generation). This local differentiation allows the turbine to maintain high efficiency with fewer total blades, reducing the moment of inertia.
2Productivity
If the number of blades is increased to convert high-velocity flows to torque efficiently, then the efficiency is improved, but the moment of inertia increases, resulting in decreased transient response
Solution Approach 1:
The turbine rotor blade is segmented into two distinct functional portions: a hub-side impulse blade portion and a shroud-side reaction blade portion. This segmentation allows each portion to perform its specialized function independently, enabling the turbine to achieve high efficiency without requiring a large number of blades throughout the entire radius, thus avoiding excessive moment of inertia.
Solution Approach 2:
Different portions of the turbine rotor blade are given different local qualities and functions. The hub-side portion is designed with impulse blade characteristics (optimized for high-velocity flow conversion), while the shroud-side portion is designed with reaction blade characteristics (optimized for torque generation). This local differentiation allows the turbine to maintain high efficiency with fewer total blades, reducing the moment of inertia.
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 configuration effectively converts high-velocity flows into torque with improved efficiency and transient response, matching the performance of larger radius reaction blades while maintaining a smaller rotor moment of inertia, thus optimizing turbine performance.
Implementation Method 1
intermediate blades arranged in the circumferential direction between the main blades and arranged so as to extend from an inlet portion of the main blades to an intermediate portion, and having an intermediate height with respect to the height of the main blades, the fluid from the hub-side inflow passageway being allowed to flow in through front edges of the intermediate blades
Implementation Method 2
a shroud-side inflow passageway formed between a shroud-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the shroud-side partition wall surface, the fluid flowing through the shroud-side inflow passageway in a generally radial direction to a shroud-side inlet of the turbine rotor blades
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
An object is to provide a mixed flow turbine, wherein intermediate blades having an intermediate height are provided between main blades of the mixed flow turbine, thus improving an impulse blade turbine characteristic and reducing the moment of inertia for a rotor blade as a whole, thereby improving the efficiency and transient response. The mixed flow turbine includes: a turbine rotor blade 11; a turbine housing 3; a scroll partition wall 17 dividing a scroll chamber 13; a shroud-side inflow passageway 35 formed on the side of a shroud-side partition wall surface 25; and a hub-side inflow passageway 29 formed on the side of a hub-side partition wall surface 23, wherein the rotor blade 11 includes: main blades 37 formed with a height spanning the entire extent between a hub outer circumferential surface 31 and the inner periphery surface of a shroud portion 15; and intermediate blades 39 arranged in the circumferential direction between the main blades 37 and arranged so as to extend from the inlet portion of the main blades 37 to an intermediate portion and having an intermediate height with respect to the height of the main blades 37, wherein a fluid from the hub-side inflow passageway 29 flows in through front edges of the intermediate blades 39.