Abstract
It is known that small quantities of surfactant additives can greatly reduce the friction factors. This is because the generation of turbulent vortices is suppressed by the formation of rod-like micelles, and the flow remains laminar. However, the heat transfer coefficients decrease during flow laminarization. The research objective is to examine heat transfer enhancement effects by air injection. This paper presents an experimental investigation on the heat transfer characteristics in an air-surfactant solution two-phase flow through a vertical tube. Heat transfer coefficients and friction factors were much larger for the air-surfactant solution two-phase flow than for surfactant solution. However, they were smaller than an air-water. It seems to be due to drag reduction effects of micelle structure. The flow patterns were investigated by visualization. The flow pattern of air-surfactant solution two-phase flow changed from a slug flow to a churn flow or from a churn flow to a bubbly flow at low liquid phase Reynolds number compared with the case of air-water two-phase flow on fixed air flow rate.
