The use of drag reduction agent and a detergent for drag reduction in circulatory vertical pipe flow

This paper describes the results of an experimental study of drag reduction in a circulatory vertical pipe system for both upward and downward flows using a drag reduction agent, corrosion inhibitor, and a cheap detergent (washing-up liquid) with various concentrations for different flow rates. It was found that the corrosion inhibitor did not produce any drag reduction effect for both upward and downward flows while the drag reduction agent was effective for both flows; whereas, the detergent was effective only for upward flow. A comparison of the effectiveness of the drag reduction agent against the detergent showed that the effectiveness of the drag reduction agent is much higher than that of the detergent. The effect of liquid detergent is only noticeable if a large concentration is used. A 1000-ppm of detergent produces the same results as 25 ppm of drag reduction agent, which undermined the lower cost of the detergent. Over the range of Reynolds numbers tested the maximum drag reduction for upward flow is 35% while for the downward flow is 42%.