Turbomachine Cooling Housing Ball-Joint Attachment

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Solution Overview

Problem

Conventional turbomachine cooling devices using air jets face challenges in maintaining a constant air gap between the housing and the outer casing, leading to potential contact during thermal expansion, especially during takeoff when the casing dilates differently at its flanges and outer surface.

Innovation Solution

The attachment device employs ball-joint connections with cupped and recessed washers, along with elastic return members and cylindrical sockets, allowing for relative movement between the housing and the casing to maintain a consistent air gap and prevent contact, utilizing upstream and downstream retention devices with oblong openings and shoulders for precise alignment and movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the housing is rigidly attached to the outer casing using conventional flange connections, then the structural stability and manufacturing precision are improved, but the air gap between the housing and casing becomes unstable during thermal expansion, leading to potential contact and reduced reliability

Engineering Contradiction:

Improvestability of air gapVSAvoidcomplexity of attachment device

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The attachment device incorporates ball-joint connections that allow the housing to dynamically adjust its position relative to the outer casing during thermal expansion. The ball-joint mechanism enables rotational movement and positional adjustment, transforming the rigid static connection into a dynamic adaptive connection that maintains the air gap stability while accommodating dimensional changes in the casing.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the air gap between the housing and outer casing is reduced to maintain constant spacing, then the cooling efficiency is improved, but the risk of contact during thermal expansion increases, reducing the safety margin

Engineering Contradiction:

Improvecooling efficiencyVSAvoidsafety against contact

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The ball-joint connection acts as a pre-configured cushioning mechanism that anticipates thermal expansion issues. By allowing controlled movement and positional adjustment before contact occurs, the mechanism prevents the harmful effect of housing-casing contact while maintaining the optimized small air gap for cooling efficiency throughout operational thermal cycles.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If conventional rigid flange connections are used to attach the housing, then the ease of manufacture is improved, but the adaptability to differential thermal expansion is reduced, leading to potential contact during takeoff phases

Engineering Contradiction:

Improveease of housing attachmentVSAvoidadaptability to thermal expansion

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The attachment device is segmented into multiple independent components including ball-joint elements, retention devices, and adjustable connection points. This segmentation allows each component to independently accommodate thermal expansion movements while maintaining the overall structural integrity, providing adaptability to differential expansion without requiring complete redesign of the attachment system.

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 solution ensures a relatively constant air gap between the cooling tubes and the casing, preventing contact and maintaining effective cooling performance across varying flight phases by accommodating differential dilations, thus enhancing the operational reliability and safety of turbomachines.

Implementation Method 1

during the operation of the turbomachine and particularly during the takeoff of the aircraft, it is noted that a high thermal gradient exists between the upstream and downstream flanges that are considered to be 'cold,' and the outer surface (called the 'skin') of the outer casing 154 that is considered to be 'hot.' Thus the flanges dilate radially less than the rest of the casing 154

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

said attachment device comprises two retention devices using ball-joint connection, called 'upstream,' configured to connect each the upstream end of the housing to an outer face of the outer casing while allowing the movement of this upstream end relative to the outer face of the outer casing

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11753958B2Device for cooling an outer casing of a turbomachine and turbomachine provided with such a device

Publication Date: 2023.09.12 SAFRAN AIRCRAFT ENGINES SAS

AI summary

The present invention relates to a device for cooling, using air jets, an external casing of a turbomachine, comprising a housing for supplying air to cooling tubes of said casing, the housing being provided with an attachment device on the external casing. According to the invention, said attachment device comprises two upstream ball joint retention devices which each connect the housing to the external casing.