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This paper presents a preliminary study of a novel type of turbulizers based on the jet pump working principle and designed to intensify heat transfer in double-tube heat exchangers. To determine the potential for their use, Computational Fluid Dynamics (CFD) and realizable k-ε turbulence model were applied to four turbulizers differing in the angles and diameters of the nozzle and diffuser. During studies, a number of parameters were determined, including: (i) Euler number Eu, (ii) overall heat transfer coefficient kT and (iii) reduced ratio of heat duty to mechanical power 𝜀r; and then compared with data available for strip turbulizers. The tests yielded the following maximum values of: Eu - 1.5 times higher, kT - 2 times higher, and 𝜀𝑟 - 27 times higher than those obtained by classical strip turbulizers, which indicates the high potential of presented jet pump turbulizers and justifies their further development. [ABSTRACT FROM AUTHOR]

A major limitation of Computational Fluid Dynamics application in modelling devices with complex configuration is generating a numerical mesh that can accurately recreate the fluid domain without exceeding available computational power. To simplify the geometry of the impossible to simulate traditionally Pall rings and brush turbulators, the porous media model was implemented. In this research, we simulated the pressure drop in the double-pipe heat exchanger filled with eleven turbulators of different kinds (including: Pall rings, spiral packing, stamped sheet, brush, spring, and twisted tape). The viscous and inertial coefficients of the porous media were calculated for each turbulator and implemented in the calculations. The results were compared with the collected experimental data, which demonstrated the satisfactory accuracy of this approach. It is concluded that the porous media model performs especially well for the brush and spiral packing turbulators. [ABSTRACT FROM AUTHOR]