Applied Physics and Mathematics Annotation << Back INITIAL THERMAL SECTION OF A MEDIUM MOVING IN PISTON MODE WITH AXIAL THERMAL CONDUCTIVITY THROUGH A FLAT CHANNEL WITH CONSTANT WALL TEMPERATURE A.V. RYAZHSKIKH, A.A. KRASNOV, I.G. DROZDOV, V.I. RYAZHSKIKH A comparative analysis of the lengths of the initial thermal sections and local Nusselt numbers was carried out when the medium moves in the ideal displacement mode in a flat horizontal channel with constant wall temperatures, taking into account and without taking into account the longitudinal thermal conductivity of the flow. From the obtained analytical solution of the linear initial-boundary value problem of convective heat transfer of the Graetz type, the range of Peclet numbers is determined for which the integration of the axial thermal conductivity of the medium flow leads to an inaccuracy in determining the length of the initial thermal section. Keywords: flat channel, initial thermal section, axial thermal conductivity, ideal displacement mode flat channel, hydrodynamic entrance region, Newtonian fluid. DOI: 10.25791/pfi m.02.2024.1292 Pp. 17-22.