HydroDynamic coefficients for an autonomous underwater vehicle (AUV) are obtained by simulating the maneuver tests in Computational Fluid Dynamic (CFD) media. The simulations are performed for different length to diameter ratios by STAR-CCM+ software. Also the effects of different hydroplanes as a hull appendage is investigated. HydroDynamic forces and moment are computed and by using suitable curve fitting linear and nonlinear hydroDynamic coefficients are calculated. The results show that by increasing the length to diameter ratio the higher hydroDynamic coefficients can be obtained. The comparison of simulated results with the available experimental data shows a very good agreement among them.

Mixer- settlers are widely used for solvent extraction process in industry. The aims of this project are simulation of Fluid flow and optimizing the operational conditions of settler in solvent extraction process. Designing and meshing of settler geometry is done by Gambit software. Then, in order to simulate the Fluid flow, the meshed designed imported to Ansys Fluent software. Simulation results were verified before simulation. Effect of Inlet volumetric on phase separation investigated. The effect of geometry of picket fences was investigated by the presence of cubic, cylindrical picket fences, picket fences with 5 corner cross section and half cylindrical picket fences. A few extra plates of picket fences were located near the entrance of settler. Phase separation in presence of two and three rows of picket fences investigated. Results indicate that by reducing the inlet volumetric rate, increasing the number of rows, putting extra plates of picket fences in front of entrance and decreasing the closed to open surface ratio to 2, separation improves.

Hydrocyclones are the most efficient used classifiers in the grinding circuits. Hydrocyclones are normally modeled and simulated using empirical models. These models can only be used within the range of the experimental data from which the model parameters have been derived. Computational Fluid Dynamics (CFD) is a powerful tool in simulating Fluid flow in hydrocyclones. This research work deals with 3D simulation and modeling of Fluid flow in a single phase hydrocyclone using CFD. The main simulation steps include preparing the geometry, meshing it, defining the properties of the materials involved, and setting the boundary layer and conditions. The experimenal data measured in a laboratory hydrocyclone were used for validation of the model. The simulation results indicated that the tangential velocity increased traversing towards the core, before decreasing at the interface with the air core. The liquid axial velocity inside the hydrocyclone varied from-1. 59 m/s to 6. 52 m/s. The axial velocity is a result of two swirling flows, the inner upward flowing inside the air core and the outer downward flowing near the cyclone wall. The liquid axial velocity inside the hydrocyclone varied from-5. 58 m/s to 5. 46 m/s. The LES model showed the least error on predicting the velocity profiles, the air core dimensions (7. 8%), the pressure drop (7. 52%) and the mass split ratio to overflow (0. 18%). The effect of various geometric (spigot diameter, vortex diameter and cone angle) and process (feed flow rate) parameters on tangential velocity of the Fluid was investigated.

Many diseases are related to cerebrospinal Fluid (CSF) hydroDynamics. Therefore, understanding the hydroDynamics of CSF flow and intracranial pressure is helpful for obtaining deeper knowledge of pathological processes and providing better treatments. Furthermore, engineering a reliable Computational method is promising approach for fabricating in vitro models which is essential for inventing generic medicines.A Fluid-Solid Interaction (FSI) model was constructed to simulate CSF flow. An important problem in modeling the CSF flow is the diastolic back flow. In this article, using both rigid and flexible conditions for ventricular system allowed us to evaluate the effect of surrounding brain tissue. Our model assumed an elastic wall for the ventricles and a pulsatile CSF input as its boundary conditions. A comparison of the results and the experimental data was done. The flexible model gave better results because it could reproduce the diastolic back flow mentioned in clinical research studies. The previous rigid models have ignored the brain parenchyma interaction with CSF and so had not reported the back flow during the diastolic time. In this Computational Fluid Dynamic (CFD) analysis, the CSF pressure and flow velocity in different areas were concordant with the experimental data.

Hydrate formation in refinery gas pipelines is one of the major problems of refinery gas companies. There are a large number of investigations about this phenomenon. The neccessity of facing this problem has been considered in many cases. Some chemical methods and technologies have been used in order to inhibit the hydrate formation in pipelines or to predict it. In this study, a Computational Fluid Dynamic (CFD) modeling was employed to predict the probability of hydrate formation in the gas pipeline. The proposed model was validated using the operational data of Ilam refinery gas pipeline. The pipeline was simulated and the results were compared with the experimental data. The obtained numerical results showed enough agreement with the experimental data. Regarding pressure gradient in the pipeline, hydrate formation temperature was calculated and the possibility of hydrate formation in the pipeline was evaluated according to the comparison between the hydrate formation temperature and the actual temperature. In addition, various parameters such as inlet temperature, ambient temperature, and gas flow rate were studied in order to find the hydrate formation probability using the sensitivity analysis method. Results showed that the inlet and ambient temperatures are usually higher than the hydrate formation temperature, so the probability of hydrate formation is low in the pipeline. Moreover, the results clearly showed that increasing the gas flow rate or decreasing the gas inlet temperature can increase the probability of hydrate formation in the pipeline.

The separation efficiency and pressure drop of the Dynamic separator of cement particles can be affected by many factors, like structural type, geometric parameters, and operating characteristics. In this paper, CFD modeling is applied to investigate the Fluid flow behavior and the efficiency of the industrial Dynamic separator with different heights of the inner cone called the vortex breaker. Simulations are based on the RSM and the DPM models. A CFD comparison of the original design and new designs has been performed. The simulation results showed that the Fluid flow inside the industrial air separator is greatly dependent on the height of the vortex breaker. Interesting phenomena were observed by the numerical simulations and the results revealed that an increase in the height of the vortex breaker up to three-quarters of the magnitude of the fine powder outlet duct can improve the performances of particle separation not only by reducing 29% the cut size, and by 40% the bypassing of fine particles but also by increasing 30% the separation sharpness while keeping the pressure drop substantially unchanged.

The three-dimensional oil-water flow in horizontal pipe has been investigated by introducing population balance equation (PBE). The water fraction of inlet flow and mixture velocity varies from 46% to 60% and from1. 25 m/s to 3m/s, respectively. The multiple size groups model has been applied to the non-uniform drop size distribution in oil-water flow. The drop coalescence models have a clear efficacy on the prediction capability of the PBE. In this work, drop coalescence model for oil-water is modified and used for predicting the phase distribution of dispersed oil-water in horizontal pipe. Population balance with modified Coulaloglou’ s frequency model is used. The attention of the modification is on the presence of droplets that reduce the free space for droplet motion and cause an enhancement in the collision frequency. The phase distribution profile from numerical results is presented and discussed. Acceptable agreement with the experimental data is achieved by using the modified coalescence model. Also, at 46% water fraction and mixture velocity equal as 3 m/s, model with population balance with modified Coulaloglou is 4% and 1% better than Luo’ s model and Coulaloglou’ s model, respectively.

A two Fluid model (TFM) was used to study gas-solid heat transfer in a riser with different inclination angles. A two dimensional pipe with 5. 8 cm internal diameter and 5 meter length was chosen. Effect of bed angle and solid particles feed rate were studied on the heat transfer behavior of gas and solid particles. Obtained results from simulation are compared with the experimental data in the relevant literature. Heat transfer behavior of phases is different in an inclined pipe in comparison with vertical and horizontal pipes. It is found that higher air-solid Nusselt number, air temperature difference and particle temperature difference take place at the pipe with inclination angle equal to 45 degrees. Loading ratio enhancement increases gas temperature differences. At lower and higher loading ratio, particles temperature differences decreases and increases respectively with loading ratio enhancement.