Burnout in steam-water flow on horizontal tubes

The mechanism of the burnout occurrence in a steam-fluid medium flowing about a horizontal steam-generating tube is analysed. The analysis is based on the burnout hydrodynamic nature. A formula for calculation of the critical heat flux is obtained that is correlated with experimental data. The experiments have been performed with horizontal electrically heated tubes, with 6 and 16 mm external diameter. The tube, 6 mm in diameter, was situated in a planar vertical 11 mm wide slit. The experiments have been conducted at the 0.1 MPa pressure, 0.058 and 1.25 m/s steam flow rate and 0.95% void fraction. The 16 mm diameter tube was mounted in the upper row of the horizontal bundle of 32 such tubes arranged at a 40 mm pitch in a vertical slit 37 mm wide. The experiments with this tube have been performed under 7.5 MPa pressure, 0.4 m/s flow rate and 0.65% void fraction. Under operating conditions investigated the suggested formula may be recommended for calculating critical heat fluxes in steam generators and heat exhangers with boiling coolants in the intertube space of horizontal bundles of tubes