Abstract:
The heating of oil and oil products is widely used to reduce energy losses during transportation. An approach is developed to determine the effective length of the heat exchanger and the
temperature of the cold coolant (oil) at its outlet in the case of a strong dependence of oil viscosity on
temperature. Oil from the Uzen field (Kazakhstan) is considered as a heated coolant, and water is
considered as a heating component. The method of the log–mean temperature difference, modified
for the case of variable viscosity, and the methods of computational fluid dynamics (CFD) are used
for calculations. The results of the numerical calculations are compared with the data obtained on
the basis of a theoretical approach at a constant viscosity. When using a theoretical approach with a
constant or variable viscosity, the heat transfer coefficients to cold and hot coolants are found using
criterion dependencies. The Reynolds-averaged Navier–Stokes (RANS) and a turbulence model that
takes into account the laminar–turbulent transition are applied. In the case of variable oil viscosity, a
transition from the laminar flow regime to the turbulent one is manifested, which has a significant
effect on the effective length of the heat exchanger. The obtained results of the CFD calculations are
of interest for the design of heat exchangers of a new type, for example, helicoid ones
