Trip Strips in Minicore Cooling Passage Network

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Solution Overview

Problem

Gas turbine engines face inefficiencies in cooling air distribution and heat transfer within the airfoil structure, particularly due to limited convective surface area and boundary layer turbulence, which affects the engine's performance and thermal management.

Innovation Solution

The integration of a cooling passage network with inlet orifices, sub-passages, and trip strips within the airfoil outer wall, where trip strips are strategically placed to enhance convective surface area and turbulate the boundary layer, improving heat transfer and pressure loss characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional cooling passage network is used in the airfoil wall, then the structure is simple and easy to manufacture, but the heat transfer efficiency is limited due to insufficient convective surface area and boundary layer turbulence

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidcooling passage structure complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent introduces trip strips as porous-like surface features within the cooling passage network. These trip strips create turbulence and increase effective surface area for heat transfer, similar to how porous materials increase surface area while maintaining structural integrity. The trip strips are integrated into the cooling passage walls, providing enhanced convective heat transfer without requiring complete reconstruction of the cooling system architecture.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent adds trip strips that extend into the cooling passage flow path from the airfoil wall surface. This dimensional addition creates three-dimensional turbulence structures within the otherwise two-dimensional boundary layer, significantly enhancing heat transfer efficiency by disrupting laminar flow and increasing convective mixing across the passage cross-section.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Temperature

If trip strips are added to the cooling passage network, then heat transfer efficiency is enhanced through increased convective surface area and boundary layer turbulence, but pressure loss increases due to flow disruption

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidpressure loss

Core Design Contradiction:

TemperatureVSStress or pressure

Solution Approach 1:

The trip strips are strategically positioned at specific locations within the cooling passage network where boundary layer development and heat transfer requirements are most critical. Rather than uniformly distributing trip strips throughout the entire passage system, the invention applies them locally to regions where they provide maximum heat transfer benefit while minimizing overall pressure loss impact on the cooling air flow.

Inventive Principle:

Principle #3Local quality

3Temperature

If the cooling passage network is embedded in the airfoil wall between inner and outer portions, then thermal management is improved, but the structural wall thickness is reduced and manufacturing complexity increases

Engineering Contradiction:

Improvethermal managementVSAvoidairfoil wall manufacturing

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The cooling passage network is segmented into multiple discrete passages embedded within the airfoil wall structure, with trip strips further segmenting each passage into regions of enhanced and standard heat transfer. This segmentation allows the complex thermal management function to be distributed throughout the wall structure, enabling manufacturing through conventional investment casting or additive manufacturing techniques that can handle internal geometries.

Inventive Principle:

Principle #1Segmentation

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 significantly enhances heat transfer efficiency and pressure loss management, leading to improved thermal management and performance of the gas turbine engine by optimizing cooling air distribution and convective surface area.

Implementation Method 1

trip strips for mixing cooling air in the cooling passage network

Methodology Applied

Scientific EffectTurbulence: Turbulence

Implementation Method 2

trip strips for mixing cooling air in the cooling passage network

Methodology Applied

Scientific EffectBoundary layer: Boundary Layer

Implementation Method 3

cooling passage network embedded in the article wall between inner and outer portions of the article wall

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS11339718B2Minicore cooling passage network having trip strips

Publication Date: 2022.05.24 RTX CORP

AI summary

A gas turbine engine article includes an article wall that defines leading and trailing ends and first and second sides that join the leading and trailing ends. The article wall defines a cavity. A cooling passage network is embedded in the article wall between inner and outer portions of the article wall. The cooling passage network has an inlet orifice through the inner portion of the article wall to receive cooling air from the cavity, a plurality of sub-passages that extend axially from the at least one inlet orifice, at least one outlet orifice through the outer portion of the airfoil wall, and trip strips for mixing cooling air in the cooling passage network.