Enhanced heat transfer of drag reducing surfactant solutions with fluted tube-in-tube heat exchanger

Solutions containing drag reducing additives also show reduced heat transfer which limits their use in hydronic cooling and heating systems where heat exchange is critical. For Reynolds numbers 10,000–50,000 and test fluid inlet temperatures 50–70°C, a fluted inner tube heat exchanger showed increased heat transfer coefficients for both cationic and zwitterionic/anionic drag reducing surfactant solutions. The pressure drop penalty for heat transfer enhancement of the cationic surfactant solution flowing through the fluted tube is high while for the zwitterionic/anionic solution, significant heat transfer improvement was achieved with only a modest pressure drop penalty.