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Turbo Fan Installation and Removal Tool

IP.com Disclosure Number: IPCOM000241444D
Publication Date: 2015-Apr-28
Document File: 6 page(s) / 330K

Publishing Venue

The IP.com Prior Art Database

Related People

Shawn Alstad: INVENTOR [+2]

Abstract

A front fan or blisk fan is a largest fan diameter in a turbo fan engine with a very small tip clearance from the fan containment housing. The smaller tip clearance enhances the performance of the engine by reducing the tip flow leakage. The blisk fan experiences a high wear and tear during operation, and the probability of getting damaged is high compared to other engine components. If the blisk fan gets damaged or dented, it must be repaired or replaced for proper operation of the fan and engine. The smaller tip clearance between blisk fan blades and fan containment housing makes it difficult to remove and then install the blisk fan without damaging the engine inlet and fan containment housing. The proper alignment between the blisk fan and the fan containment housing is required during installation and removal to prevent them from damage. The existing tools for close alignment of the fan and the fan housing centerlines are very costly, heavy and complex. This paper proposes a novel, cost effective and lightweight tool to prevent damage to the fan blades and the fan housing during installation and removal of the blisk fan. The proposed semi-rigid protective blade tip covers the blade tip and bears all the wear and tear during installation and removal which in-turn protects the blade tip and the other engine components. The thickness of the tip cover also helps to maintain the close alignment of the fan and the fan containment housing centerlines.

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Turbo Fan Installation and Removal Tool

Shawn Alstad and Danis Burton Smith ABSTRACT

A front fan or blisk fan is a largest fan diameter in a turbo fan engine with a very small tip clearance from the fan containment housing. The smaller tip clearance enhances the performance of the engine by reducing the tip flow leakage. The blisk fan experiences a high wear and tear during operation, and the probability of getting damaged is high compared to other engine components. If the blisk fan gets damaged or dented, it must be repaired or replaced for proper operation of the fan and engine. The smaller tip clearance between blisk fan blades and fan containment housing makes it difficult to remove and then install the blisk fan without damaging the engine inlet and fan containment housing. The proper alignment between the blisk fan and the fan containment housing is required during installation and removal to prevent them from damage. The existing tools for close alignment of the fan and the fan housing centerlines are very costly, heavy and complex. This paper proposes a novel, cost effective and lightweight tool to prevent damage to the fan blades and the fan housing during installation and removal of the blisk fan. The proposed semi-rigid protective blade tip covers the blade tip and bears all the wear and tear during installation and removal which in-turn protects the blade tip and the other engine components. The thickness of the tip cover also helps to maintain the close alignment of the fan and the fan containment housing centerlines.


1. Introduction

Turbo fan engines with a high bypass ratio are widely used in commercial aircraft to provide higher propulsive efficiency. The turbo fan engine contains a front fan attached to the main shaft of the engine. The front fan sucks atmospheric air into the inlet as it rotates. This air is either diverted into the bypass flow path or it is diverted into the

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engine core, where it is further compressed, injected with fuel, and ignited. The hot and pressurized combustion gases expand and rotate the turbine. The turbine further rotates the front fan and various stages of compressors attached to the main shaft.

There are various methods to design the front fan of the turbofan engine, the first method involves interlocking each individual blade with a central hub. This allows each blade to be removed independently when a blade is damaged. The second method permanently fixes all of the blades to the central hub. This is achievable either by welding, machining the entire fan from a single metal billet, or by composite layup. This integral multi-blade and central hub is known as a blisk fan.

The components of the turbofan engine are exposed to extreme conditions during operation. The front fan particularly bears high wear and tear. Damage to the front fan of turbofan engine could lead to higher fuel consumption or reduce specific fuel consumption. If the front blade gets damaged, chippe...