Use of strip coils to intensify heat exchange in media having anomalous viscosity

Abstract

While spiral inserts of twisted strip are widely used as a method of improving heat transfer by the generation of secondary flows under the action of centrifugal forces in normal viscosity liquids, there are no data related to improving convective heat exchange of anomalously viscious media by the spiral coil method. An experimental rig is set up to obtain such data. Results indicate that spiral inserts improve heat exchange in anomalous viscosity liquids exceeding several fold the similar effects in normal viscosity liquids. The insert originates spiral channel centrifugal forces, decreases the free cross section, and introduces a fining effect, all of which influence heat transfer. Further study shows that the most effective use of spiral inserts of twisted strip is achieved at high Prandtl number ranges.