A comparison between a small in-line and a staggered tube bank condensing steam filmwise at low-pressures

Abstract

Abstract Data have been produced for filmwise condensation of steam, and steam–air mixtures, flowing downwards across two tube bank, a 15 row, in-line bank containing 75 tubes and a 15 row staggered bank containing 82 tubes. Both banks were tested at conditions 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 10,000 ppm. Steam to cooling water temperature differences of 5, 10 and 15 K were used to generate heat fluxes of up to 90 kW / m 2 . The data and a mathematical model were used to investigate the effect of geometry difference on the heat transfer and pressure difference characteristics. For this particular configuration, the staggered and the in-line tube banks gave the same performance. This is not consistent with similar studies done by other researchers and indicates that tube spacing is important.