Numerical calculation of the hydrodynamics of heat carriers, taking into account the dependence ofviscosity on temperature

Abstract

The article is devoted to the study of the hydrodynamics of heat carriers in heat exchangers. Giventhe widespread use of this device, increasing its thermal and hydraulic characteristics has become so important for theirdesigners. In the work, the calculation of non-stationary flows of liquids through the heat exchanger tubes is carried out.Water ("hot" coolant) and oil ("cold" coolant) are used as heat carriers, between which heat exchange occurs through thesolid surface of the pipeline, which is the boundary between the heat carriers. When calculating the movement of oil, thefact was taken into account that the dynamic viscosity depends very much on temperature and, depending on temperature,the Reynolds numbers also change. And, as a consequence, when flowing through a sufficiently thin channel, the flow regimechanges, namely, the transition from the laminar flow regime to the turbulent one is manifested, while this effect is notobserved with the analytical calculation method for constant viscosity. The Reynolds-averaged Navier-Stokes equations,closed using the turbulence model, were used for numerical modeling of fluid dynamics of heat carriers. Verification of theheat exchanger calculations was carried out in the software package "Ansys Fluent".