What is the function of balance piston in steam turbine, how it function and how the steam flow to the piston?

Question

What is the function of balance piston in steam turbine, how it function and how the steam flow to the piston?

Answer 1

The balance piston actually has nothng to do with balance. It has to do with counteracting thrust. When high pressure steam enters the first stage turbine wheel there will be a (pressure X area) thrust toward the low pressure end. This occurrs in each successive stage. The balance piston disc is arranged on the turbine wheel so that some high pressure steam is introduced on the low pressure side to push the other way. This takes load off of the thrust bearing.