Asymmetric Trip Strip Reflection Layout for Long Cooling Passages

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Solution Overview

Problem

In gas turbine engines, the asymmetric nature of skewed trip strips leads to non-uniform heat exchange and degraded heat transfer performance in longer passages due to thermal saturation of fluid, which reduces the ability to transfer heat effectively.

Innovation Solution

The implementation of periodic reflections of skewed trip strips along the flow passage, with a frequency of length-to-diameter ratio ≤ 20, where the orientation of trip strips is periodically altered or reversed relative to the passage center, to maintain uniform temperature and enhance heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If skewed trip strips are used to reduce pressure loss, then pressure drop is reduced, but heat transfer performance degrades in longer passages due to thermal saturation

Engineering Contradiction:
Improvepressure lossVSAvoidheat transfer performance
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies periodic reflection of skewed trip strips at regular intervals (L/d ≤ 20) along the flow passage. This periodic arrangement prevents thermal saturation by periodically resetting the temperature profile, maintaining heat transfer effectiveness throughout long passages while preserving the low pressure loss benefits of skewed trip strips

Inventive Principle:
Principle #19Periodic action

2Loss of energy

If asymmetric trip strip configuration is used, then pressure loss is reduced, but temperature profile becomes non-uniform leading to thermal saturation

Engineering Contradiction:
Improvepressure lossVSAvoidtemperature uniformity
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The patent uses asymmetric skewed trip strips that are reflected periodically rather than symmetrically. The asymmetric configuration reduces pressure loss, while the periodic reflection compensates for the resulting temperature non-uniformity by resetting the thermal profile at regular intervals, preventing thermal saturation

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

Periodic reflection at intervals of L/d ≤ 20 creates a repeating pattern that prevents the accumulation of thermal saturation effects, maintaining temperature uniformity throughout the passage length

Inventive Principle:
Principle #19Periodic action

3Reliability

If trip strips are placed in long passages, then heat exchange is enhanced, but thermal saturation occurs reducing heat transfer ability

Engineering Contradiction:
Improveheat transfer performanceVSAvoidheat transfer ability
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

By implementing periodic reflection of trip strips at regular intervals (L/d ≤ 20), the patent prevents thermal saturation from developing in long passages. Each reflection resets the temperature profile, maintaining the heat transfer ability throughout the entire passage length

Inventive Principle:
Principle #19Periodic action

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 approach prevents heat transfer decay and maintains efficient heat exchange performance in longer passages with minimal impact on pressure drop characteristics, ensuring effective heat transfer across the passage length.

Implementation Method 1

a boundary layer separates upstream and downstream of the ribs. These flow separations reattach the boundary layer to the heat transfer surface

Methodology Applied
Scientific EffectFlow separation: Flow Separation

Implementation Method 2

The separated boundary layer enhances turbulent mixing, and therefore the heat from the near-surface fluid can more effectively get dissipated to the main flow

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 3

The separated boundary layer enhances turbulent mixing, and therefore the heat from the near-surface fluid can more effectively get dissipated to the main flow

Methodology Applied
Scientific EffectTurbulent mixing: Turbulence

Data Source

PatentEP4450760A1Layout for asymmetric trip strips, layout for asymmetric trip strips for a component for a gas turbine engine and process for managing a fluid flow through a flow passage having asymmetric trip strips for a gas turbine engine component
Publication Date: 2024.10.23 RTX CORP
  • EP4450760A1 patent drawingFigure 1
  • EP4450760A1 patent drawingFigure 2~4
  • EP4450760A1 patent drawingFigure 5

AI summary

A layout for asymmetric trip strips (128) including a flow passage (100) having a lower wall (122) and an upper wall (124) opposite the lower wall (122), each of the lower wall (122) and the upper wall (124) including an inner surface (118), the flow passage (100) having a passage inlet (136) and a length L and a diameter d; multiple skewed trip strips (128) extending from at least one inner surface (118) of the lower wall (122) or the upper wall (124); and at least one periodic reflection (140) of the skewed trip strips (128) along the flow passage (100) downstream of the passage inlet (136) at a frequency with a length-to-diameter ratio of L/d≤20. A layout for asymmetric trip strips (128) for a component for a gas turbine engine (20) and a process for managing a fluid (116) flow through a flow passage (100) having asymmetric trip strips (128) for a gas turbine engine (20) component are also disclosed.