Abstract: This paper describes the experimental results on boiling heat transfer and frictional pressure drop of high pressure steam-water two-phase flow in internally ribbed tubes used in once-through boilers of 300MW thermal power plants. The boiling heat transfer characteristics in a vertical upward ribbed tube were experimentally investigated under the conditions of pressure from 9.8 to 22.6 Mpa, mass velocity from 650 to 1750kg/m3﹒s, and inside wall heat four from 200 to 610kW/m2. The adiabatic frictional pressure drop in a horizontal ribbed tube was measured under the conditions of pressure from 9.8 to 20.6MPa, mass velocity from 1530 to 3560kg/m2﹒s, and steam quality from 0.0 to 1.0. Based on the experiments, the wall temperature profiles of the ribbed tube and the effectivemess of the ribbed tubes for eliminating boiling heat transfer deterioration are obtained, and a correlation for calculating frictional pressure drop in the ribbed tudes is presented. The heat transfer characteristics of three typed of internally ribbed tubes with a similar internal configuration are compared and evaluated.

Key words: 电站锅炉, 沸腾传热, 摩擦阻力, 内螺纹管