computational fluid dynamics

In this study, the influence of type and structure of different roofing systems were investigated using computational fluid dynamic method. The considered roofing systems include beam and block types (clay brick, light weight concrete block, polystyrene) and Uboot slab which were designed for 6m and 8m span. To simulate the fluid flow and heat transfer, the computational fluid dynamic method was employed based on control volume scheme. Heat transfer inside air cavities is carried out via free convection and radiation while heat transfers via conduction within solid walls. The thermal simulation of the roofing systems was analyzed for both summer (downward heat flow) and winter (upward heat flow). Two dimensional natural heat transfer was considered to be transient with laminar and incompressible flow inside cavities. To assess the thermal performance of the flooring systems, equivalent thermal conductivity, decrement factor and time lag were studied. Finally, the best roofing system was introduced in terms of heat transfer and thermal mass efficiency. The results showed that the roof with polystyrene block has the lowest value of equivalent thermal conductivity and Uboot system has the highest heat loss among the studied cases.

Augmented reality is one of the new technologies in recent decade that has appeared especially in mobile devices. In augmented reality, virtual objects are placed in a real environment, next to other real objects. Another reason for the importance of augmented reality is the implementation of augmented reality applications on mobile and personal devices such as smartphones and tablets. The integration of augmented reality with a numerical simulation method such as computational fluid dynamics provides a cognitive, scientific and efficient tool for expert and non-professional users to analyze practical problems. In addition, using computational fluid dynamics techniques and an augmented reality-based system, engineering analysis and simulation results are obtained directly on real-world objects, resulting in a better understanding and relationship between the simulation results and the world. It becomes real. In this research, the combination of augmented reality and computational fluid dynamics method has been used to implement an Android software to simulate the thermal changes of solids with different materials over time.

The deposition of pharmaceutical aerosols and pathogenic particles are considered when predicting certain pulmonary disorders or determining the dose of respiratory drugs in order to control and manage the diseases. The breathing and flow pattern, particle size and density, airways geometry and the gravitational force exerted on the particles are among the factors contributing to the deposition in the respiratory tract. In this study, modification of the flow pattern in the respiratory tract was investigated by applying different boundary conditions on the outlet and the effects of various flow patterns on the deposition of the iron particles was studied. Keeping some of these patterns, the impact of exerting gravitational forces with different directions and values (from the microgravity to normal condition on the earth) on the particles was examined. The inflow with velocities of 2 and 4m/s was used in order to change the nature of the flow from laminar to turbulent. Two particle sizes of 4 and 8 microns for iron particles were assumed. As a result, deposition of particles increased with an increase in the gravitational force and the effect of changing the direction of the gravity from the X direction (aligned with the flow direction) to the Y direction (perpendicular to the flow) was shown to be a significant factor in a further increase of particle deposition. The modified flow pattern which was free of any reverse and secondary flow, has reduced the deposition values and resulted in an opposite effect increasing the size of iron particles.

Rotating Packed Beds (RPBs) are used in many processes of chemical engineering, such as distillation, absorption, production of nanoparticles, natural gas sweetening, and etc. The fluid flow analysis in this equipment is necessary to obtain the hydrodynamic information and investigation of transport phenomena. In this paper, 3D simulation of single phase and two phase flows are carried out using Computational Fluid Dynamics (CFD). The effect of some parameters such as rotational speed, gas and liquid flow rates, number of rotor holes, fixed and moving baffle are investigated on the pressure drop. The single phase flow analysis showed that the tangential velocity has the most effect on the velocity magnitude comparison with the radial and axial velocities. The simulation results showed that dry and wet pressure drop increase with increasing gas flow rate as the average errors between experimental data and simulation results with and without baffle are 5.3% and 3.6%, respectively. It was also known that increasing liquid flow rate has negligible effect on the pressure drop. It was seen that wet pressure drop increases with increasing both rotational speed and rotor holes. The moving baffle insertion into the bed was caused that wet pressure drop decreases 14%.