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We present both experimental and numerical simulations for a static mixing device that combines two fluids of different viscosities through a porous media. Experimentally, the mixing extent was determined by CCD detection. We showed that the porous plug dramatically improved the mixer performance. The numerical simulation identified the zones where the mixing was developed in the system as the mixing component mass flow could be plotted. The mixing principally occurred downstream the porous plug which initiated a jet flow due to the viscosities contrast of the two fluids. For a better...
The effects of an industrial gas turbine’s Exhaust Collector Box (ECB) geometry on static pressure recovery and total pressure loss were investigated in this study. This study aims to further understand how exit boundary conditions affect the performance of a diffuser system. In this investigation, the exhaust diffuser remained constant through each test, with collector box geometries being varied. The same uniform velocity profile was maintained at the diffuser inlet for all geometries considered. The local pressure recovery through the diffuser with 4 axial ports at 4 circumferential...
As numerical methods, digital prototypes and immersive engineering definitely gain more and more acceptance within the civil engineering community, there is a remarkable variety of additional applications coming along with this tendency. The Fire & Smoke feature within STAR-CCM+ is already intensively used to investigate fire scenarios in road and rail tunnels, underground stations as well as public buildings to develop safety and rescue plans in the case of emergency. Public authorities more frequently accept and even ask for respective studies to safeguard administrative decisions...
We present a hybrid atomistic–continuum method for multiscale simulations of dense fluids. In this method, the atomistic part is described using a molecular dynamics description, while the continuum flow is described by a finite volume discretization of the incompressible Navier–Stokes equations. The two descriptions are combined in a domain decomposition formulation using the Schwarz alternating method. A novel method has been proposed in order to impose non-periodic velocity boundary conditions from the continuum to the atomistic domain, based on an effective boundary potential, consistent...
In order to evaluate the performance of jet impingement for high heat-flux cooling, experimental cooling loops based on water and liquid metal jet impingement were designed and constructed. The current liquid metal system, based on an eutectic alloy of gallium and indium (GaIn) with a melting point of 15.7 °C, employs an annular inductive electromagnetic pump. The experiments showed that it is capable of accommodating a heat flux of about 20 MW/m 2 over an area of 10 −4 m 2 . The jet velocity is less than 4 m/s and the required differential pressure from the pump is less than 10 5 Pa. In the...
Jet impingement is a well established cooling methodology used for cooling turbine blades in gas turbine engines. Jet impingement results in high heat transfer coefficients as compared to other conventional modes of single phase heat transfer.Most of the research in jet impingement has been confined to high Reynolds number regime. In order to increase the applicability of this technique to non conventional applications like in a low pressure micro turbine combustors or turbine blades, the behavior of such systems in the low Reynolds number regime should be understood. The present paper is a...
Nuclear vendors and utilities perform numerous simulations and analyses in order to ensure the safe operation of nuclear power plants (NPPs). In general, the simulations are carried out using vendor-specific design codes and best-estimate system analysis codes, most of which were developed based on one-dimensional lumped parameter models. During the past decade, however, computers, parallel computation methods, and three-dimensional computational fluid dynamics (CFD) codes have been dramatically enhanced. The use of advanced commercial CFD codes is considered beneficial in the safety analysis...
This paper reports a computational fluid dynamics (CFD) study on influence of flow field on to gas residence time in boiler furnace. Specifically, investigated was secondary air nozzle direction influence on level of elimination of dead and recirculation zones.As residence time is a ratio between effective furnace volume and gas flow rate from the solid bed,increase of the former through elimination of dead zones would lead to increase of the residence time,and it as a consequence would have an increase of combustion efficiency. Small-scale biomass boilers are specific in a way that their...
Aerodynamics plays an important role in marketing vehicles especially with the recent increases in gas prices. The aerodynamics of one of the widely used vehicle classes (pickup trucks) is examined. The focus is to investigate the effect of the pickup truck configuration on the structure of the airflow around the vehicle and ultimately on the generated aerodynamic drag. The study includes CFD simulations performed using STAR-CCM+ developed by CD-adapco Inc. and full-scale wind tunnel testing conducted in the Langley Full Scale Tunnel (LFST) located at the NASA Langley Research Center but...

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