Simulation and analysis of two phase Flow that crosses over tube bundles is crucial in safety analysis and design of kettle reboilers and steam generators. The geometry complexity of the tube bundle Flow Field increases the difficulty of the conventional numerical analysis. One of the methods to reduce the numerical calculations cost is to use the porous media theory instead of the complete tube bundle modeling. Drag and tube bundle resistance force equations have been used in the porous media analysis. Based on available experimental results, two tube bundle arrangements have been considered. Due to existence of symmetric geometry and uniform energy source over the tube bundle, the two dimensional symmetric models have been used as well. It was observed that the predicted pressure drop in this research has acceptable adaptation with the experimental results. Meanwhile, by considering different outlet boundary conditions, calculated void fraction is compared to the experimental results and showed better accuracy than similar CFD research. It was observed that the enhancement of the tube bundle thermal power increases the void fraction in the heating area of the reboiler.

Introduction: The computational fluid dynamics (CFD) Simulation of three-dimensional wire-plate electrostatic precipitator is performed in the present study. Materials and methods: The momentum equation, the electric potential equation and current continuity equation are solved by using ANSYS Fluent. The ion charge density at the corona is calculated iteratively using the Peek formula. The SIMPLE algorithm is used to treat the pressure-velocity coupling. The RNG k-ε model is used to describe turbulence. Results: The airFlow keeps stable away from the first corona electrode. The distribution of the electric potential is dependent on the wire-plate distance and the wire-wire distance. The potential and ion charge density increase with the increase of the wire-plate distance. With the increase of wire-wire distance, the maximum electric Field strength decreases whereas the maximum ionic charge density increases. The ion charge density near the second corona electrode is relatively small. A small wire-wire distance will make the electric Field concentrated around the wires. Conclusion: According to this study, the wire-wire distance and the wire-plate distance have great effect on the distribution of ion charge density and electric Field strength.

The steady Reynolds-Averaged Navier-Stokes (RANS) method with the Realizable k - e turbulence model was used to analyze the Flow Field around a race car (generic Formula One). This study was conducted using the ANSYS software package. The numerical Simulations were conducted at a Reynolds number based on the race car model (14.9´106). The time-averaged velocity Field, Flow topology, velocity magnitude, static pressure magnitude and vortex regions of the Flow Fields are presented in this paper. The measurements were performed on the vertical and cross-sectional planes. The results are presented graphically, showing the main characteristics of the Flow Field around the whole race car, whereas most previous studies only mention the Flow Field around individual components of race cars. The Realizable k - e turbulence model results showed consistency with the valuable validation data, which helps to elucidate the Flow Field around a model generic Formula one race car.

Using an existing control volume based computer code, swirling Flow Field and combustion of fuel and air are computed. In order to model turbulent stresses, a modified Bossinisque scheme in swirling Flows is used. Turbulent Flow is modeled using a RNG k-ε model and combustion is modeled by two well-known models, i.e., the bi-molecular Arrhenius relation and the EBU (Eddy Break Up) model. The results of the numerical solution of a combustion chamber are compared with the existing experimental data for velocity and temperature distributions. The comparison shows satisfactory agreement between numerical and experimental results. The lower reaction rate computed using the above models is used in the computation. In this study, variable fluid properties have been used and their effects are presented. It is shown that the existence of either swirl or combustion shortens the length of the recirculating region and the same effect is produced by using RNG k-€ instead of the standard turbulence model.    

In this research, the steady-state Flow filed around a 3D body and rotor configuration of the ROBIN helicopter is simulated. The rotor is modeled by an actuator disk. For this purpose, an annular computational domain replaces the rotor and some modeled source terms are added to the momentum equations. This modeling of rotor considerably speed up computational time. The Flow Field over this helicopter fuselage is simulated for six cases of different advance ratios and thrust coefficients. The accuracy of using uniform, linear and BET distributions for the rotor in the source term is investigated. With the BET and some corrections to pitch angles, pressure coefficients and variation of thrust and power of rotor are predicted in agreement with experimental data. For the nominal thrust coefficient of 0.06, different loading methods on rotor using experimental results are compared for two advance ratio of 0.05 and 0.23. In the advance ratio of 0.23 for the upper surface of helicopter, no considerable difference among the different employed methods is observed. However, for the advance ratio of 0.05 and for the side that helicopter blades get closer to the body (Starboard side), the results with the modified methods are better than BET method. The presence of strut in the computational domain has important effects in high speeds and causes reduction of pressure coefficients over body especially in downstream of the strut.

Sediment transport in irrigation canals is an important issue in the design and operation of irrigation systems. The vortex‐ settling basin (VSB) is a small scale, efficient, and economical device that using only the Flow vortices to remove sediments. Most studies which explain Flow patterns in VSBs are experimentally based on velocity measurements inside the VSBs in the laboratoary, and mathematical modeling studies are rare. The SSIIM model was used in this study to simulate the three-dimensional velocity distribution in a VSB, and the Flow distribution obtained from available turbulence models in SSIIM were compared with experimental measurements. The results showed that the SSIIM model is able to capture the main features of the Flow Field, including the central vortex and secondary Flows near the walls. The results also indicate that tangential velocity follows the combined Rankin vortex only in regions far from the inlet and outlet channels; however, this statement is not true in other regions. The k-ε turbulence model produces unacceptable results for the tangential velocity distribution, while both the tangential and radial velocity distributions obtained from the k-ω model are in reasonable agreement with laboratory measurements.