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In dispersed two-phase flows, the particle size is probably the most important parameter in determining the particle dynamics. Interphase forces, heat and mass transfers are all functions of the particle diameter. Diameters of the particles are unlikely to be uniform and for droplets and bubbles they can change continuously due to breakup and coalescence. Methods of moments have been used very successfully in modeling particle size distributions in dispersed two-phase flows. The model described in this paper is based on the method of moment. It contains models for droplet breakup and...
Numerical simulations of gas-liquid two-phase flow with high superficial velocity in a vertical pipe were conducted with the use of the commercial software package STAR-CD 3.27. Detailed description of the Sγ model is presented. The applicability and performance of the Sγ model in Eulerian modelling of gas-liquid bubbly flow were studied. The sensitivity of the Sγ model to the distribution moment γ, and the drainage mode were also investigated. The numerical results were compared with the available experimental data of Hibiki et al., (2001). Good agreement was achieved for the phase axial...
Numerical simulations of gas-liquid two-phase flow with high superficial velocity in a vertical pipe were conducted with the use of the commercial software package STAR-CD 3.27. The change in bubble size due to breakup and coalescence was modelled by the S γ model. The applicability and performance of the S γ model in modelling of gas-liquid bubbly flow were studied. The sensitivity of the S γ model to the distribution moment γ , and the drainage mode were investigated. The numerical results were compared with the experimental data of Hibiki et al., (2001). Good agreement was achieved for...
Spark-less jet ignition pre-chambers are enablers of high efficiencies and load control by quantity of fuel injected when coupled with direct injection of main chamber fuel, thus permitting always lean burn bulk stratified combustion. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the pre-chamber, where it mixes with the air entering from the main chamber. Combustion of the air and fuel mixture then starts within the pre-chamber because of the high temperature of the hot glow plug, and then jets of partially combusted hot gases enter the main...
A computational fluid dynamics approach incorporating the Lagrangian framework is employed to model the impingement, mixing, and subsequent combustion in a liquid rocket engine with liquid oxygen and liquid methane propellants. Due to its high performance, non-toxicity and the fact that it might be manufactured on Mars, methane is being considered for a variety of future exploration missions by NASA and others. The objective of this investigation is to assess the capabilities of current state-of-the-art CFD methodology based on a Lagrangian framework to model the associated multi-phase, multi...
Solid handling and processing are widely carried out in process and steel industries. For examples – charging of solid raw materials into a blast furnace; injection of solid coal particles into a blast furnace along with hot gas; conversion of solid coal into solid (porous) coke in a coke-making unit; transport of coal, pneumatic conveying of sintered pellets, etc. Modeling the flow of these solids employing continuum approach has proved to be a big challenge for the researchers. Proper insight into the mechanics that cause the motion of the granular material is still not achieved. Recently,...
The policy framework regulating the emissions of oxides of nitrogen from industrial and utility boilers is in flux. As such, most owners are taking the opportunity to evaluate potential strategies for when, not if, more stringent NOx reduction regulations are put into service. The armada of aging, moderately sized boilers that have been skipped over in the previous wave of Selective Catalytic Reduction (SCR) installations, due to an assumption that they would be eventually replaced with new generation assets, are now in focus as owners are forced to extend the expected lifetimes of these...
In some countries, summer over-heating is a big problem in a building’s energy balance. Ventilated façades are a useful tool when applied to building design, especially in bioclimatic building design. A ventilated façade is a complex, multi-layer structural solution that enables dry installation of the covering elements. The objective of this paper is to quantify of the improvement in the efficiency of the thermal behaviour of buildings when this sort of façade is installed. These improvements are related to the ventilation capacity of the additional structure to the shield mainly for saving...
Computational Fluid Dynamics has been integrated as a key component of missile aerodynamic performance analyses at Lockheed Martin Missiles & Fire Control for many years. Applications are varied, including preliminary aerodynamic databases, identifying component loading, investigating complex flow fields, and assessing safe separation. A discussion of the procedures and tools used is presented, with specific emphasis on STAR-CCM+. Aerodynamic performance predictions from STAR-CCM+ and an in-house code are compared to wind tunnel test data at several Mach numbers for the Joint Common...
A mesh optimization strategy for accurately estimating the drag of a ground vehicle is proposed based on examining the effect of different mesh parameters. The optimized mesh parameters were selected using a Design of Experiments (DoE) method enabling simulations to be carried out in a limited memory environment, and in a timely manner; without compromising the accuracy of results. The study was extended to take into account the effect of model size. A simplified car model at three scales has been investigated and compared with results from the MIRA model wind tunnel. Parameters that lead to...

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