Modeling of heat transfer and hydrodynamics of water-oil heat carriers in heat exchangers

Increased energy efficiency in the extraction and transportation of highly viscous oil is achieved by reducing its viscosity through heating. Numerical modeling is a powerful tool for developing and analyzing methods to improve heat transfer efficiency and optimize the design of heat exchange devices in the oil and gas industry. To solve this problem, the study uses Reynolds-averaged Navier-Stokes equations supplemented with turbulence models (k-ε, k-ω SST, and Transition SST) capable of accounting for the transition from laminar flow to turbulent flow with variable viscosity. The results of calculations of smooth and spiral pipes are compared, as well as an assessment of the reliability and performance of turbulence models used to simulate the operation of heat exchangers with direct and reverse heat flow. The dependences of the numbers Nu and Re of the oil flow in a washed by water pipe for all three turbulence models are shown in comparison with the corresponding experimental result, indicating the qualitative agreement of the numerical calculation results with the experiment. The results of the comparative analysis showed that the kw SST model most effectively describes the flow movement in the inter-tube space. The Computational Fluid Dynamics calculation data obtained is of practical importance for the design and optimization of heat exchanger structures.