Tilted Cone Diffuser for Turbine Exhaust Flow Distortion
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Solution Overview
Problem
Conventional annular diffusers in turbine exhaust systems suffer from flow distortion due to a 90-degree turn, leading to uneven mass flow distribution and reduced pressure recovery, often requiring complex and costly geometries to mitigate these issues.
Innovation Solution
An annular diffuser with a radially symmetrical, frusto-conical outer cone tilted relative to the turbine shaft, paired with a collector that turns exhaust gases 90 degrees, maintains uniform mass flow and enhances pressure recovery without increasing axial length or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional annular diffuser with a 90-degree collector turn is used, then the exhaust system can redirect flow, but flow distortion occurs causing uneven mass flow distribution and reduced pressure recovery
Solution Approach 1:
The patent applies asymmetry by tilting the outer cone of the annular diffuser relative to the turbine shaft axis. This asymmetric configuration (with tilt angles of 3-7 degrees) compensates for the flow distortion caused by the 90-degree collector turn, redistributing mass flow more uniformly across the diffuser exit and improving pressure recovery without requiring complex internal geometries
2Loss of energy
If complex geometries are used to mitigate flow distortion, then pressure recovery improves, but manufacturing costs and axial length increase
Solution Approach 1:
The patent changes the geometric parameter of the outer cone by introducing a tilt angle (3-7 degrees) relative to the turbine shaft axis. This parameter modification simplifies the diffuser geometry compared to complex internal structures, reducing manufacturing complexity and cost while effectively improving pressure recovery by optimizing mass flow distribution
3Loss of energy
If complex geometries with increased axial length are used, then flow distortion is mitigated, but the exhaust system becomes longer and more complex
Solution Approach 1:
The tilted outer cone configuration achieves flow distortion mitigation within a compact axial length by asymmetrically redistributing mass flow. This approach avoids the need for extended axial lengths required by complex geometries, maintaining a compact exhaust system design while improving pressure recovery
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 tilted outer cone design achieves uniform pressure recovery and reduced losses, improving overall exhaust system performance by maintaining similar mass flow per unit area across the circumference, resulting in enhanced pressure recovery without increasing manufacturing costs or complexity.
Implementation Method 1
the 90-degree in the collector distorts the flow field in the diffuser by causing mass flow to move toward the bottom and having much more diffusion near the top than on the bottom
Implementation Method 2
improving pressure recovery while also providing little increase in complexity and manufacturing costs
Data Source
AI summary
An exhaust system for a turbine includes an annular diffuser and a collector. The annular diffuser is positioned adjacent to a final stage of the turbine and includes a hub portion surrounding a turbine shaft and an outer cone having a substantially frusto-conical shape that is radially symmetrical about a central longitudinal axis thereof that is tilted relative to the turbine shaft. The collector has an inlet extending from the annular diffuser and an outlet. The collector is configured to include a turn that causes the collector to turn exhaust gases approximately 90° from the longitudinal axis of the turbine shaft. The outer cone of the annular diffuser is tilted in a direction of the turn of the collector.