An experimental study of low-pressure filmwise condensation on a small in-line tube bank

A purpose-built test facility has been constructed and used to produce data for filmwise condensation from steam, and steam-air mixtures, flowing down wards across a 15 row by 5 column bundle of tubes. Data were obtained at co nditions typical of those found in the UK electricity generating industry. Steam was supplied at pressures of 50, 75 and 100 mbar, at velocities of 10 , 20 and 33 m/s and with air concentrations of 0 and 10000 ppm. Steam to co oling water temperature differences of 5, 10 and 15 K were used to generate heat fluxes of up to 90 kW/m(2). The data were used to investigate the app lication of existing correlations for shell-side heal transfer, inundation and non-condensable gas concentration to tube bundle design. It is shown th at the selection of an appropriate steam velocity allows good agreement bet ween some shell-side heat transfer correlations and the experimental data, and that existing correlations for inundation and air-concentration effects are sufficient.