A. Bagheri - Aerospace Engineering Department, Kish International Campus, University of Tehran, Kish, Iran
S. Karimian Aliabadi - Aerospace Engineering, University of Tarbiat Modares, Tehran, Iran
F. Ommi - Aerospace Engineering, University of Tarbiat Modares, Tehran, Iran
K. Ghaemi Osgouie - Aerospace Engineering Department, Kish International Campus, University of Tehran, Kish, Iran

Herein, a non-boiling two-phase flow containing air and water through a downward flow in a vertical tube with helical corrugations has been investigated. In this simulation, various flow rates for air and water are considered, and three corrugation pitches ۱, ۱.۵, and ۲ cm are included. It can be seen in the results that the pressure drop values decrease with an increase in volume fraction. It should be noted that the reduction of pressure drop values with the reduction of volume fraction (VF) is based on the reduction of the water flow rate, which is visible. By comparing the pressure drop values for each corrugation pitch, it can be seen that as the pitch decreases, the pressure drop values increase significantly. The results for Nusselt number show that Nusselt number decreased with an increase in the volume fraction. By reducing the water flow rate, the intensity of the main flow is reduced the intensity of turbulence is also reduced and the heat transfer coefficient is reduced. Ultimately, the cost-benefit ratio has been utilized to show real results for each studied case.

Air Injection, Cost-benefit ratio, Helicoidal corrugations, Nu number, Pressure drop