Flow in a gas-lift digester with a central draft-tube was investigated using computational fluid dynamics (CFD) and different turbulence closure models. The k-ω Shear-Stress-Transport (SST), Renormalization-Group (RNG) k-∊, Linear Reynolds-Stress-Model (RSM) and Transition-SST models were tested for a gas-lift loop reactor under Newtonian flow conditions validated against published experimental...

In this paper, a double-cyclone is used as a gas-solid separator in the fluid bed-drying process to prepare dry HDPE powder from a wet feed of 56000 kg/hr. The quality of dry HDPE depends mainly on particles behavior and flow pattern in the dryer which affect the double-cyclones as an effective equipment in this process. Controlling of the inlet carrier gas causes excellent flow pattern, desire...

Computational Fluid Dynamics (CFD) is used to predict natural ventilation flows in an enclosure with upper and lower openings connected to the environment. The natural driving forces are wind combined with buoyancy. CFD simulations were carried out by varying the strengths of buoyancy under a constant assisting wind effect. Simulation results of the volume flow rates through the enclosure, the ...

Design of muffler system strongly influences engine efficiency and noise level. Hence, comprehension of flow characteristics inside muffler system is very important. In this study, numerical study of three-dimensional steady and unsteady compressible flow inside muffler system attached to 4-cylinder engine was performed to identify the flow characteristics. To obtain the boundary conditions for...

In this research, a gas turbine blade cascade was investigated. Flow analysis around the blade was conducted using RSM and RNG.K-ε turbulence modeling and it is simulated by Fluent software. The results were considered for the cases as Mach number loss at the trailing edge of blade caused by vortexes that were generated at the end of blade. Effect of cooling flow through the trailing edge on th...

The power transmitters, guyed masts and other lattice structures are exposed to wind action. aerodynamic forces acting on tall tower constructions have crucial importance the stability of structure. structure drag coefficient determination is subject international standards ESDU 81027 81028 Eurocode 3 Part 3.1, but it can also be determined by numerical methods. For that purpose modelling using...

Scour is a phenomenon that occurs as a result of natural erosion by ground water flow and transport of seabed material. In this research, scour around the legs of marine structures is simulated using the FLOW3D.V.9.3™ commercial software. The general scour model consists of two components, namely, the lift and thrust forces. The drag force, that is inserted to the structure, is a combination of...

We briefly address general aspects that reliable security evaluations of physical RNGs should consider. Then we discuss an efficient RNG design that is based on a pair of noisy diodes. The main contribution of this paper is the formulation and the analysis of the corresponding stochastic model which interestingly also fits to other RNG designs. We prove a theorem that provides tight lower bound...

This paper focuses on the implementation, validation and exploitation of a vertical dropshaft flow operation using the commercial VOF-based Computational Fluid Dynamics (CFD) code, FLOW-3D ® . Using the experimental data of Chanson (2002), the package was used to simulate the flow patterns in a rectangular dropshaft with plunge-flow pattern. Both k−ε and k−ε RNG turbulence closures were tested ...

To develop reliable computer models for the bluff body flow and transport of pollutants or chemical and biological (CB) agents in urban environments requires accurate measurements of the basic flow fields for carefully controlled, well-known conditions. Fluid modeling in an Industrial Wind Tunnel provides an opportunity to produce accurate simulations of the bluff body flow and transport of urb...