DRAG REDUCTION BY A CHEMICAL ADDITIVE IN CAPILLARY TUBES AND SQUARE DUCTS

This paper reports the experimental results of using a new solvent for drag reduction in capillary tubes and square ducts. It was found that the effect of adding the GEM solution on the drag reduction in the co nduits is very much dependent on the Reynolds number and diameter in q uestion and the concentration used. A maximum drag reduction of about 32% is obtained for the square section and 20.8% for capillary tubes o f 3.2 mm. The effect in the smaller diameter was not encouraging and f or a certain range of Reynolds numbers it increases the drag.