Flow pattern modulation in a horizontal tube by the passive phase separation concept

► We proposed a phase separation concept to modulate flow pattern in a tube. ► The tube has an annular region and an inner region separated by mesh pore surface. ► Liquid can be within the mesh cylinder for stratified flow modulation. ► Plug/slug/bubble flow is modulated to ensure gas phase flowing near the wall. ► Condensation heat transfer should be enhanced due to the phase separation.