I know Gas turbine axial movement is restricted by the thrust bearing but is it the only thing which restricts its axial movement? I mean such a heavy machine with so much production of power by burning huge volume of fuel...and the machine does not move at all? I Mean HOW?

 

Yes, the thrust bearing does the work of holding the turbine, compressor, and generator from chewing itself apart. The thrust bearing assembly and shaft thrust collar are a significant assembly! If you ever get the opportunity to see one apart, take it. Obviously these pieces were, indeed, sized appropriately. GE 7FAs thrust bearing has both active and in-active thrust (thrusts in both directions.) When turning gear goes on, the shaft goes to the in-active end, and at baseload, fully active. The amount of movement is 'bump' tested during a major inspection (manually jacked from one end to the other)and the total float is measured (end to end travel.) I have seen between 15 and 22 mils of total float. This value is specified and the thrust pads are shimmed to be within a certain tolerance. Alarms and trips are based off of the total float measured. A few more mils beyond that, and the unit (thrust color and thrust pads) are metal on metal, and a few more would allow buckets and blades to clash. I'm not an expert, but have seen a few...Hope this helps.