Low-Reynolds Mathematical Modeling of the Structure of Vortex Zones Between Periodic Surface-Located Flow Turbulators of Semicircular Cross-Section in Pipes

Abstract

Mathematical modeling of the structure of vortex zones between periodic surface-located flow turbulators of a semicircular and square cross-section is carried out on the basis of multi-block computational technologies based on the solution of the factorized finite-volume method of the Reynolds equations (closed with the help of the Menter shear stress transfer mode) and the energy equation (on different-scale intersecting structured grids). This method was previously successfully applied and verified by experiment. An exhaustive analysis of the corresponding streamlines is presented, proving the advantage of abruded turbulators. A well-known and very well-tested in practice method of vortex intensification of heat transfer is the application of periodic protrusions on the walls of the washed surfaces [1]. The study of the structure of the intensified flow is mainly carried out by experimental methods [1], while modern computational works on this topic are relatively few [2] and are only partially devoted directly to the structure of the intensified flow; some of the methods (for example, a certain part of works [2]) use only integral approaches to this problem. This work is directly devoted to the study of the flow structure in the pipe, For pipes with turbulators of a semicircular cross-section, the nature of the relationship between heat transfer and hydraulic resistance remains similar to the above-considered nature of the relationship for square flow turbulators, but the values (Nu/Nusm)/(  /  sm) for the former, as a rule, is definitely higher due to the much smaller influence of the systems of secondary and corner vortices, which occurs due to deformation and greater elongation of the main vortex, which is confirmed by the corresponding values for pipes with turbulators of a semicircular cross-section (Nu/ Nusm) / (  /  sm)=0.89 t/D