Semenyako A. Regularities of transfer processes in heat-transfer surfaces from flat-oval tubes with transverse fins

The dissertation is devoted to solving the actual task of the development and substantiation of scientific principles of creating effective heat exchangers from single-row systems of flat-oval finned tubes, obtained on the basis of study of the surface-averaged and local characteristics of transfer processes and determination of optimal geometric characteristics of fining. Comprehensive experimental and CFD-studies of surface-averaged and local heat transfer, aerodynamic resistance, flow characteristics and its structure were carried out with a flow of gas coolant through flat-oval tubes in the range of values of their geometrical and regime characteristics, relevant for heat-exchange equipment. Obtained are the generalized similarity equations for the calculation of the intensity of convective heat transfer and aerodynamic resistance of single-row heat exchange systems from finned flat-oval tubes, which take into account the dependence of the degree at Reynolds number from the geometric characteristics. The presented results of pressure distribution and local heat transfer coefficients, visualization, thermoanemometric and CFD-studies, on the basis of which the particularities of transport mechanisms are generalized in the form of a physical model of flow and heat transfer on the surface of finned flat-oval tubes. A methodology and program for calculating the optimal geometric characteristics of the transverse finning of flat-oval tubes, which takes into account the regime parameters of the heat-exchange surface, is developed.