Intensification of a Heat Exchange Process in Mixing and Surface Heat Exchangers

Abstract

The analysis of heat exchange intensification methods by design methods shows that the use of tubes with transversely annular turbulators enables to reach high values of heat transfer coefficients with an acceptable growth of resistance coefficients. To carry out the studies, it was proposed to use the knurled tubes with flow core turbulators in the form of spherical bulges. There have been carried out the studies of heat transfer coefficients at different Reynolds numbers and sizes of turbulizing elements.The results of these studies have shown that by increasing Reynolds numbers the values of the relative heat transfer coefficients increase too. For the intensification of heat transfer, the promising transition region is the one in which the highest values of heat transfer coefficients are observed. To describe the obtained results, the equations that take into account the mechanisms of vortex interaction behind the annular projections and spherical bulges have been introduced, as well as the relationship between the streamlined obstacle pitches. The equations have been derived by the calculation of heat transfer coefficients, describing the changes of studied parameters. The results of studies of the tube bank’s heat transfer process in mixing and surface type apparatuses have been considered, as well as the possibility of applying the derived equations of heat transfer coefficients for an adequate description of thermal processes inside them.