Turbine Stator Vane Cavity for Secondary Flow Mitigation

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Solution Overview

Problem

Turbine modules in turbomachines face inefficiencies due to secondary flows such as tip clearance losses, which lead to flow disturbances and reduced performance.

Innovation Solution

A turbine module design that bleeds a portion of the main flow from regions of higher losses into a cavity and then reinjects it downstream, using inclined holes or slots to guide the flow and reduce pressure losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the main flow passes through the stator passage with secondary flows present, then the turbine module structure remains simple, but flow losses increase due to tip clearance losses and flow disturbances

Engineering Contradiction:

Improveflow lossesVSAvoidturbine module structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The stator passage is segmented into a main channel and a cavity, allowing the flow to be divided into different paths. The inlet opens into the cavity and the outlet opens into the main channel, creating separate flow regions that can be optimized independently to reduce secondary flow losses.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cavity acts as an intermediary structure between the inlet and the main channel outlet. It provides a separate path for the main flow to traverse through the stator passage, isolating it from the harmful secondary flows in the main channel while still allowing structural support and flow guidance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If cooling air passages are added to the stator vane airfoil, then flow separation is prevented and efficiency improves, but the device complexity increases

Engineering Contradiction:

Improveturbine efficiencyVSAvoidcooling system structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The cavity serves multiple functions: it provides a separate flow path to reduce secondary flow losses, acts as a cooling air passage to prevent flow separation, and maintains structural support for the stator vane airfoil. This multi-functionality improves turbine efficiency without proportionally increasing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 mitigates the harmful effects of secondary flows, improves flow characteristics, prevents flow separation, and enhances circumferential mixing, leading to increased turbine efficiency.

Implementation Method 1

prevent a flow separation in the main channel

Methodology Applied

Scientific EffectFlow separation: Flow Separation

Implementation Method 2

energise a boundary layer

Methodology Applied

Scientific EffectBoundary layer: Boundary Layer

Data Source

PatentEP4123124B1A turbine module for a turbomachine and use of this module

Publication Date: 2025.06.04 MTU AERO ENGINES GMBH

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AI summary

A turbine module (2) for a turbomachine (1), the turbine module (2) comprises, a main channel (26) to guide a main flow (36) through the turbine module (2), a rotor blade (21) and a stator vane (22), the stator vane (22) comprising a stator airfoil (22) and a platform(23), with the stator airfoil (22) arranged downstream of the rotor blade (21) in the main channel (26), and a cavity (30) comprising an inlet (31) for injecting a part (36.2) of the main flow (36) into the cavity (30), an outlet (32) for a reinjection of the part (36.2) of the main flow (36) from the cavity (30) into the main channel (26), wherein the cavity (30) is arranged at an axial position of the stator vane (20) and is radially offset from the stator airfoil (22).