EFFECTS OF LEAKAGE COOLING ON IP ROTOR DISC AND ROOT IN 600MW STEAM TURBINE

Numerical simulation is performed on the first two stages of IP cylinder of a 600MW steam turbine using CFD and CHT methods. Cooling effects of HP cylinder leakage steam on IP cylinder rotor is investigated and flow behavior of the leakage steam in cooling passages is studied, with configurations of seals, root bottom gaps and diaphragm-to-disc gaps included. Efficient cooling effects are achieved on the rotor and blade root of the first stage, with highest temperature decrease being up to 90K. No obvious cooling effects are found on the second stage rotor blade and rotor disc. Maximum temperature of rotor groove for first and second stage appears at trailing and leading side of its meshing surface with root flat, with value being 796K and 803K separately, which are 41K and 34K lower than the temperature of IP cylinder fresh mean steam.