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Petrochemical furnaces are used in the petrochemical industry for the preheating of crude oil, residue, gasoil, naphtha, kerosene, and diesel through refining operations. When the fluid flows inside the furnace pipes, thermal cracking occurs. During the heating process, a generation of lighter fractions of petroleum and coke formation takes place. Coke adheres to the wall of the pipes, increasing pressure drop and internally insulating the pipes. Consequently, heat transfer is affected. In most of these processes, during heating and thermal cracking, gases are generated, forming a liquid‐gas two‐phase flow in the pipe. In this work, thermal cracking and gas generation are represented by a kinetic net which takes into account the constituent fractions of the petroleum load, which are represented by six pseudo‐components. The CFD model was able to predict the lighter petroleum fractions and the gas generation as well as the coke formation inside the tube. Coke concentration increases along the pipe as the average temperature of the mixture increases.

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Uma forma de propiciar o entendimento dos fatores que influenciam na qualidade do ambiente é o uso de ferramentas computacionais. A técnica de fluidodinâmica computacional (CFD) tem sido uma alternativa para permitir a busca de soluções, por meio de simulações que possibilitam o estudo de diferentes cenários que seriam onerosos se houvesse a necessidade de realizá-los experimentalmente. Assim, o objetivo deste trabalho foi realizar simulações de CFD, com o software livre OpenFOAM, para a análise do conforto térmico em um ambiente fechado.

Ventilation systems used in swine facilities deserve to be studied because they directly affect productivity in the pig farming sector. Bearing this in mind the uniformity of air distribution and temperature is essential to animal welfare in this breeding environment. Thus, the purpose of this study was to identify whether changes in air entrances and exhaust fan positioning could influence air velocity and temperature distribution. The experimental data were collected in a commercial full-scale sow facility. Validation was carried out by comparing the simulated air temperatures and data measured in the field. These results showed agreement between data with a maximum relative error of approximately 3 %. The real settings showed a gradual increase in the air velocity from the air entrances and dead zones due to the change in airflow direction. There was no difference when the positioning of the exhaust fans was altered or was maintained in the original air entrances. The proposed arrangement with only one air inlet reduced the areas of low air movement as a consequence of the change in flow direction. Furthermore, the variables have the same pattern along the transversal plane. The simulations showed that the position of the air inlets had a higher influence on temperature distribution.

New discoveries of petroleum reservoirs in ultra deep-water depths, like Pre-salt fields in Santos Basin, are demanding new riser systems concepts. In this scenario, the Free-Standing Hybrid Riser (FSHR) system is a viable choice. A submersible buoy connected by rigid and flexible risers constitutes this riser system. The sea current can cause the Vortex-Induced Motion (VIM) of the buoy, which can increase significantly the riser fatigue damage. Although the VIM phenomenon is similar to Vortex-Induced Vibration (VIV), it generally occurs in rigid bodies with low aspect ratio, where end effects causes tridimensional flow behavior. Therefore, the vortex wake characteristics and the hydrodynamics coefficients found for VIV is no longer valid for VIM. In this context, wake oscillator models used for VIV prediction in actual form is not adequate for the VIM prediction of the buoys. In this paper, a VIV wake oscillator model is calibrated for VIM, through hydrodynamic coefficients found in the technical literature. In order to verify accuracy, the VIM calibrated wake oscillator model is used to reproduce some FSHR reduced model tests. The results of amplitude and frequency of oscillation against the reduced velocity obtained from the numerical simulation are compared with the experimental results. The numerical results presented the same trend with some differences in amplitude. The amplitude deviation could be related to the hydrodynamics coefficients used in the calibration of the wake oscillator model.

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