(481c) Drag Reduction in Dilute Gas-Solids Suspension Flow in Tubes—Revisited

In the summers of 1964-66, I worked at the NASA Lewis Research Center and studied the feasibility of using a gas-solids suspension as the working fluid in a Brayton space power system. During an extensive literature search to develop correlations for the suspension heat transfer coefficient and friction factor, I stumbled across some anomalous data which showed that the suspension heat transfer coefficient was actually lower than that of the pure gas at very low solids loading ratio. By the Reynolds analogy this should also have been observed for the friction factor but at that time no such result was reported. With support from NASA, I started a 10 year experimental and theoretical program, together with 2 PhD students, to try to gain an understanding of the phenomenon of drag reduction in dilute gas solids suspension flow. This presentation will describe our experimental techniques, experimental data, and some theoretical explanations for what was observed as well as some other more recent studies. During that time period Jacques Zakin was already well recognized for his research in drag reducing flow due to polymer and other additives to liquids. My research in this area brought us together at a number of international conferences on drag reduction and served to solidify our friendship which started when we were both graduate students at NYU.