in turbine steam expansion, the vapour first supercools and then condenses spotaneously to become a two phase mixture. the flow initially is single phase but after wilson point water droplets are developed and behavior of the liquid create problems that lower the performance of the turbine wet stage and the mechanisms underlying this are insufficiently understood. this growing droplets release their latent heat to the flow and this heat addition to the supersonic flows cause a pressure rise called condensation shock. because of irreversible heat transfer in this region the entropy will increase tremendously. removal of condensates from wet steam flow in the last stage of steam turbines significantly promotes stage efficiency and prevents erosion of rotors.

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