CT-31 Pressure Drop of Vacuum Condensation in a Vertical Tube

Z. H. Yang

Pressure drop is a critical parameter for vacuum condenser design, especially for high vacuum conditions. The current HTRI pressure drop method for vacuum condensation is an extrapolation based on limited low vacuum condensation data. To investigate the mechanism of vacuum condensation and improve prediction accuracy, we collected experimental data for tubeside vertical downflow condensation from the HTRI Low Pressure Condensation Unit (LPCU).The data confirm that the current method significantly overpredicts two-phase friction pressure drop in both mist and shear-controlled flow under high vacuum conditions (P< 3.5 kPa). Based on our experimental data, we have analyzed the flow characteristics under vacuum condensation and suggest improvements to our two-phase flow pressure drop correlations.