Turbine engine including a water system

A turbine engine comprising:

• a spool comprising:
• a compressor that compresses core air;
• a turbine;
• and
• a shaft connecting the compressor and the turbine such that the compressor and the turbine rotate together;
• a fuel supply;
• a combustor located downstream of the compressor, the combustor receiving the core air and the fuel supply, and combusts the core air and the fuel supply to generate combustion gases, the combustion gases flowing to the turbine, causing rotation of the turbine, the core air, the combustion gases, the compressor, and the turbine generating a first axial force on the spool;
• a balance piston that applies a second axial force on the spool to balance at least a portion of the first axial force, the balance piston comprising:
• a rotating boundary portion comprising a rotating portion of the spool;
• and
• a fixed enclosure portion that does not rotate, the rotating boundary portion and the fixed enclosure portion defining a balance piston cavity;
• and
• a water system providing water to the balance piston cavity, wherein the water in the balance piston cavity is a balance piston fluid, the balance piston fluid absorbing heat from the balance piston, causing an expansion and a pressure increase in the balance piston fluid generating the second axial force.