It's a condensation problem!!

In a circular tube of height 6m and dia 2.5cm hot water vapour is entering the inlet at a temperature of 150°C. Water liquid is flowing over the tube such that the surface temperature Ts is 15°C. In this process the condensation of steam takes place and we get water at exit.

How can I model this phenomenon using species transport ( multispicies ) to understand the phase transformation?