Friction and heat transfer in drag-reducing surfactant solution flow through curved pipes and elbows

Going against the flow—A review of non-additive means of drag reduction

“…Surfactants (Surface Active Agents) have been suggested by many researchers as alternative additives with the potential to act as a drag reduction agent [14][15][16][17][18][19][20][21][22][23]. As the surfactant concentration in the solution reaches the critical micelle concentration (CMC), certain assembles referred to as ''micelles'' are formed due to the polarity of the surfactant molecules.…”

Investigation of the combination of TiO2 nanoparticles and drag reducer polymer effects on the heat transfer and drag characteristics of nanofluids

“…Gasljevic and Matthys have shown that the heat transfer and friction factor coefficients for high molecular weight polymers go together; their results clearly demonstrate that the reduction in the heat transfer rate is greater than the reduction in pressure drop …”

“…Moreover, thermal degradation can be seen at high temperatures, so as long as the system works at low temperatures, polymers can reduce the drag force; however, at higher temperatures, surfactants can be used instead of polymers, owing to the fact that, unlike polymers, surfactants do not suffer from permanent degradation and they have a greater resistance to mechanical and temperature degradation. For instance, polyacrylamide may degrade in a few hours at 90 °C, while it can take many hours at 7 °C …”

“…In 1948, this remarkable phenomenon was observed for the first time . However, the implementation of drag reduction agents in heat exchanger systems is harmful because they reduce the heat transfer coefficient; the ratio of the heat transfer reduction to friction factor is 1.3–1.5, depending on the flow velocity …”

Flow of drag-reducing surfactant solutions in rough pipes

“…Hitherto, the studies on drag reduction induced by an addition of surfactants have concerned the flow in hydraulically smooth pipes [18,32,33], curved pipes and elbows [4,34,35] and in square ducts [36]. Zakin et al [32] and independently Aguilar et al [33] derived the equations describing the asymptotes of the maximum drag reduction (MDRA) for surfactant solutions.…”