Avaliação de correlações para parâmetros de escoamento em tubos utilizando CFD
Resumen
The fluid flow inside tubes is present in many industrial operations and the knowledge of the flow parameters is essential for the processes to be optimized. The analytical solutions found in the literature are obtained only for simple flow configurations. For more complex cases, empirical solutions are the way found to overcome the difficulty of analyzing these cases, in contrast, the number of proposed correlations and the divergence between them becomes a problem in deciding which is the best to be used. In this work, simulations of circular tube with length of 0,1m, 0,2m, 0,4m, 0,7m, 1,2m, 1,4m, 1,5m, 1,75 e 2m with water and glycerin in laminar (Re = 100, 498, 995 e 1032), transition (Re = 2488, 2986, 3154 e 3483) and turbulent (Re = 4976, 6967, 9952 e 10322) flows were performed in the Ansys Fluent software in order to obtain values for entrance length, velocity profile and pressure drop variables so that they were subsequently compared with values obtained through correlations available in the literature. The results demonstrated that the entry lengths are well predicted by the Kays equations in the laminar flow and Bhatti in the turbulent flow, but that no correlation tested showed satisfactory proximity to the values obtained in the simulation with glycerin. The simulations with water and glycerin showed good proximity to what was predicted by the parabolic profile in the laminar flow. In turbulent flow, simulations with glycerin were the closest to the profiles proposed by the power law and the universal profile. In the pressure drop, both the water simulation and the glycerin simulation had good proximity to the theoretical pressure drop, however in the turbulent flows the results between what was obtained in the simulation and the theoretical value were different.
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