In this paper, the static interaction of a train of three cylinders in a Bingham fluid is studied numerically using Computational Fluid Dynamics. The variation of drag forces for the cylinders in several configurations is investigated. Positions of the particles in relation to the reference particle are recognized by the separation distance between the cylinders. A steady state field is considered, with Bingham numbers between 5 and 150. Several separation distances (d) were considered, such that 2.0D ≤ d ≤ 6.0D where D is the cylinder diameter. The Reynolds number was chosen in the range of 5 ≤ Re ≤ 40. In particular, the effect of the separation distance, Reynolds number and Bingham number on the shape and size of the unyielded regions was investigated. The functional dependence of this region and the drag coefficient is explored. The present results reveal the significant influence of the gap between the cylinders on the drag force and the shape of the unyielded regions surrounding the cylinders. It was found that there are several configurations in which the drag forces over the first and the third cylinders are almost equal depending on variation of the Bi, Re and the separation distance.

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There is potential for optimizing thermal oxidizer plants to increase industrial energy efficiency results in environmental and economic dimension of sustainability. In the present work, genetic algorithm is implemented for three thermal oxidizer cases in three different petrochemical plants to optimize the fuel cost for the three Heat Recovery Steam Generators (HRSG's) which are going to be used for the recovery of the heat from the outlet of the thermal oxidizer units. Generally, thermal oxidizers are used in petrochemical plants to burn waste gases in the plant to reduce the environmental impact of the off-gases of plant and normally the waste heat are released to the atmosphere via a s tack. The optimization results have been compared for three cases. Five decision variables have been selected and the objective function was optimized. By increasing the fuel price, the values of thermo-economical decision variables tend to those thermodynamically optimal designs.

In the present study, the flow of a fibre suspension in a channel containing a cylinder was numerically studied for a very low Reynolds number. Further, the model was validated against previous studies by observing the flexible fibres in the shear flow. The model was employed to simulate the rigid, semi-flexible, and fully flexible fibre particle in the flow past a single cylinder. Two different fibre lengths with various flexibilities were applied in the simulations, while the initial orientation angle to the flow direction was changed between 45° ≤ θ ≤ 75°. It was shown that the influence of the fibre orientation was more significant for the larger orientation angle. The results highlighted the influence of several factors affecting the fibre particle in the flow past the cylinder.