boeing767mech From United States of America, joined Dec 2000, 1036 posts, RR: 3 Posted (2 years 3 months 4 days 3 hours ago) and read 3571 times:
So I have been doing boroscopes for a while and have noticed the higher time RB211-535E's have damage to the HPT (high pressure turbine blades) at the blade root trailing edge. Nothing to get excited about most of the time because it is within maintenance manual limits. But what is causing this damage on the roots when the noozle guide vanes in the combustion section have little or no damage????
HPT notice the dark area of the blade, (lower left corner of picture) this is the area of damage
Typical damage of high time engine of HPT
If anyone has any insight or knowledge of this I would be curious to understand the cause of damage to just this area and not the whole blade.
ferpe From France, joined Nov 2010, 2805 posts, RR: 59
Reply 3, posted (2 years 4 weeks 1 day 10 hours ago) and read 2411 times:
If you look up the CFD simulations there are on the net of the standard type turbine airfoils (2D) and the new ones designed with 3D CFD software you can see the standard ones have a highly vorticiced area at the roots. So the cause might be shedding of high energy local vortices which gradually erode the root area at the trailing edge, those dark eroded areas seems to be at the right place for that.
It shows why modern engines are more efficient, you get the transfer from gas energy to shaft hp to be more loss free.