Papers by Keyword: Fluent

Abstract: The uniformity of temperature field distribution in creep aging process is very important to the forming accuracy of components. In this paper, the temperature field distribution of 2219 aluminum alloy tank cover during aging forming is simulated by using the finite element software FLUENT, and a two-stage heating process is proposed to reduce the temperature field distribution heterogeneity. The results show that the temperature difference of the tank cover is large in the single-stage heating process, and the maximum temperature difference is above 27°C,which seriously affects the forming accuracy of the tank cover. With two-stage heating process, the temperature difference in the first stage has almost no direct impact on the forming accuracy of the top cover. In the second stage, the temperature difference of the tank cover is controlled within 10°C, compared with the single-stage heating, the maximum temperature difference is reduced by more than 17°C. The two-stage heating effectively reduces the heterogeneity of the temperature field of the top cover. The research provides technical support for the precise thermal mechanical coupling of large-scale creep aging forming components.

Abstract: The three-dimensional growth chamber model was established by GAMBIT software, and the FLUENT software was used to simulate the Vapor Phase Epitaxy ( VPE ) growth AlN material. By changing parameters, results of simulation were obtained, in turn described the effect of uniformity and concentration of AlN. The study mainly focuses on the research of flow velocities of nitrogen and argon gas, the distance from the substrate to the inner tube mouth, the substrate front-back angular height difference, the inner tube diameter, and the substrate thickness. It is discovered through the research: above parameters play a very important role in the crystal growth of AlN film, and there are optimal parameter values. The structure of growth chamber is designed and optimized according to the simulation result. By using the simulation software, experimental costs can be greatly saved, which provides a theoretical basis for the optimal growth process of high quality AlN film, and has a certain guiding role for the actual growth process.

Abstract: . Electrochemical etching is widely used to process refractory metals such as tungsten and molybdenum. Flow field is one of the crucial factors that influence the surface quality in electrochemical etching. In this paper, the electrochemical etching flow field was analyzed via FLUENT, the characteristics of flow field in electrochemical etching are studied, furthermore, the effects of four different outlet forms of electrolyte on flow field uniformity, electrolyte velocity and pressure distribution are investigated. Under the same electrolyte flow rate, the flow field characteristics of different outlet forms are analyzed by velocity vector diagram, pressure distribution nephogram, velocity and pressure curve diagram. The simulation results indicate that stable electrolyte velocity and uniform pressure distribution of flow field are obtained when the outlet form of electrolyte adopts the optimized flat. Finally, the fixture for this outlet form is designed and fabricated, and experimental verification is carried out, which shown that the flow field is uniform and the crystal plane of the workpiece is well-distributed which according with the process requirements.

Abstract: This paper presents the application of the OpenFOAM^® software package, using the IHFoam/OlaFlow solver, in the simulation of the water waves and air flow in an OWC-WEC located on a breakwater, the Mutriku power station in the north of Spain. The numerical code solves the transient Reynolds averaged Navier-Stokes (RANS) equations, using the Volume of Fluid (VoF) technique to identify the free surface. The standard k-ε turbulence model was used evaluate the Reynold stresses. Two geometries were considered: one with the pneumatic chamber completely open to the atmosphere; and other with the chamber connected to the turbine duct. The solutions obtained by OpenFOAM^® are compared with those obtained by the commercial code Fluent.

Abstract: This work presents a numerical study of the phase change process of PCM (Phase Change Materials) stored in spherical cavities. The numerical model is two-dimensional and it is composed by the equations of conservation of mass, momentum, energy and volumetric fraction, which are modeled using the enthalpy-porosity technique. The computational mesh is tetrahedral, with refinements on regions that have large thermic and fluid dynamic gradients. The numeric model was validated with result from literature. It was studied the melting process of PCM RT35, RT 55 and RT 82 in spherical cavity with constant wall temperature. Four diameters of spheres D were used (40, 60, 80 and 100 mm) and three temperature differences ΔT (10, 20 and 30 oC) between the wall temperature and the melting temperature of the PCM. Liquid fraction results from the 36 cases studied are presented. It was observed that the time required to reach a certain liquid fraction increases with the diameter and reduces with the increment of ΔT, being possible to predict the fusion time by knowing the characteristic length of the sphere. The largest percentage reduction of the fusion time was obtained with ΔT = 10 oC – 20 oC for all the D considered. The shortest fusion time was obtained with the largest ΔT combined with the smallest D. It is possible to see the dependence of the liquid fraction results in relation with the PCM properties and the its independence in relation its melting temperature, since all the PCM studied presented equal fusion time for the same ΔT and D.

Abstract: CFD solvers are commonly used in optimization problems in aerodynamics. Typical task is the search for optimal position of slotted flap. On the example is shown that the optimum predicted by CFD software can differ significantly from that found in the wind tunnel. Then the focus is on the optimal position of slotted flaps. It was examined with ANSYS Fluent CFD code with both 2D and 3D structured meshes and three different models of turbulence. Results from CFD and those of wind tunnel were compared with relevant disagreement found. Possible sources of the error are discussed and topics for further investigation in this field are suggested in conclusion.

Abstract: Flow maldistribution and specifically in distributors has been a major area of study in engineering fluid dynamics. The literature shows some of the work done on the flow distribution in parallel tubes, nozzles, and air conditioning distributors and its effect on the pressure drop as well as the energy losses in the heat exchanger. This study aims at investigating the maldistribution of the flow in various geometries of the distributor, and trying to identify the geometry that causes the least maldistribution. FLUENT 14 software was used to carry out the CFD study in a one-phase flow (liquid), as well as in two-phase flow simulations. The results obtained show that the distributor geometry type 9, has the highest maldistribution, while type 8 has the least. The effects of the dispersion cone, the orifice, as well as erroneous tilting in installation/manufacturing, on maldistribution are also investigated. The orifice might actually lead to more maldistribution. And the cone was shown to have negligible effect on maldistribution.

Abstract: Valve orifice is the common place that the cavitation easily occurs in the hydraulic systems. This paper introduces a criteria to estimate the inception of the cavitation of the V-type valve orifice with the stress state. Based on this criteria, a cavitation model which considers the dynamics of the cavity and incompressible gas is proposed to analyze the pressure, stress and the cavitation distribution of the phase in the V-type orifice. The distributions of the cavitation along the axis and the cross section are analyzed. The simulation results show that the cavitation is easily occurred in the downstream just after the orifice and the bubbles are mostly gathered in the top of the cross section which is vertical to the axis of the flow field. The simulation results is reasonable according to the facts. Accordingly, the cavitation of the V-type orifice is predicted reasonably. The research and results of this paper are useful for the design of the hydraulic valves.

Abstract: The paper investigates the properly designed Intake or Inlet Manifold (IM) is vital for the optimal performance of an Internal Combustion (IC) engine. The primary function of the intake manifold is to evenly distribute the combustion mixture (or just air in a direct injection engine) to each intake performance of the engine. Even distribution is important to optimize the efficiency and performance of the engine. It is known that uneven air distribution leads to less volumetric efficiency, increased fuel consumption and also power loss. The main objective of the present work was to make a computational study of flow distribution in an intake manifold under steady state turbulence conditions in the current project work an intake manifold for 3-cylinder engine was modeled and analyzed numerically for evaluating the fluid flow. In this process, the geometric model was created with approximate dimensions (by using curves and points) in ANSA a pre-processing tool and the analysis was carried out using STAR CCM+ which is a solver and post-processing tool port in the cylinder head (s).

Abstract: In order to study the law between the internal coolant flow rate and the temperature of milling roller, the temperature field of water-cooled roller was simulated with Fluent software. The results showed that with the increase of the coolant flow rate, the temperature on roller surface decreased, but after the flow rate of coolant increased to 3.5 kg/s, the temperature of roller maintained invariant almost, so 3.5 kg/s was the best flow rate.