A novel structure of vertical trisection helical baffle feed water heater can enhance the heat transfer by effectively draining the condensate with inclined baffles and separating water droplets from vapor due to centrifugal force in helix channels.The draining film effect of inclined baffles and the impact of spiral flow on condensation heat transfer in a vertical trisection helical baffle condenser were numerically simulated.These simulation schemes include the Nusselt condensation models under the conditions of pure steam or in presence of non-condensable gas, the vertical trisection helical baffle condenser schemes with baffle inclined angles of 15°, 25° and 35° and the segmental baffle scheme in the presence of non-condensable gas.The results demonstrate that the condensation heat transfer increases with the decrease of inclined angle of helical baffles, and in the presence of non-condensable gas, the average condensation heat transfer coefficients of three trisection helical baffle schemes with inclined angles of 15°, 25° and 35° and the segmental baffle scheme are 89.7%, 75.7%, 58.2% and 33.1% higher than that of the bare tube bundle of Nusselt condensation model.