New approaches to numerical simulation of two-component droplet evaporation

AbstractBased on the improved computational fluid dynamics and discrete element method (CFD-DEM), heat transfer and two-component flow of biomass and quartz sand have been studied from experiments and numerical simulation in this paper. During experiments, the particle temperature and moving images are respectively recorded by infrared thermal imager and high speed camera. With the increase of the velocity, the mixing index (MI) and the cooling rate of the particles are rising. Due to larger heat capacity and mass, the temperature of biomass drops slower than that of quartz sand. Fictitious element method is employed to solve the incompatibility of the traditional CFD-DEM where the cylindrical biomass are considered as an aggregation of numerous fictitious sphere particles arranged in certain sequence. By the comparison of data collected by infrared thermal imager and the simulated results, it can be concluded that experimental data is basically agreement with numerical simulation results. Directly affected by inflow air (25℃), the average temperature of particles in the bed height area (h>30 mm) is about 3 degrees lower than that of the other heights. When the superficial gas velocity is larger, the fluidization is good, and the gas temperature distribution is more uniform in the whole area. On the contrary, bubbles are not easy to produce and the fluidization is restricted at lower superficial gas velocity. Gas-solid heat transfer mainly exists under the bed height of 10 mm, and decreases rapidly on fluidized bed height. The mixing index (MI) is employed to quantitatively discuss the mixing effectiveness, which first rises accelerate, then rising speed decreases, finally tends to a upper limit.

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A Level-Set Method for the Direct Numerical Simulation of Particle Motion in Droplet Evaporation

Numerical Heat Transfer Part B Fundamentals ◽

10.1080/10407790.2015.1052309 ◽

2015 ◽

Vol 68 (6) ◽

pp. 479-494 ◽

Cited By ~ 11

Author(s):

Hochan Hwang ◽

Gihun Son

Keyword(s):

Numerical Simulation ◽

Direct Numerical Simulation ◽

Level Set Method ◽

Level Set ◽

Particle Motion ◽

Droplet Evaporation

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Design, Simulation and SFF Techniques for Functional Components

Volume 7B: 26th Biennial Mechanisms and Robotics Conference ◽

10.1115/detc2000/mech-14205 ◽

2000 ◽

Author(s):

Noshir Langrana ◽

Dan Qiu ◽

Guohua Wu ◽

Kathryn Higgins ◽

Cheng Tiao Hsieh

Keyword(s):

Numerical Simulation ◽

Stainless Steel ◽

Rapid Prototyping ◽

Computational Models ◽

Solid Freeform Fabrication ◽

Turbine Blades ◽

Freeform Fabrication ◽

New Approaches ◽

Functional Components

Abstract Development of Solid Freeform Fabrication (SFF) systems has created the opportunity for new approaches in design of functional components, which leverages the inherent strengths of both experiment and numerical simulation. This paper describes an approach in which the computational models are integrated with the rapid prototyping fabrication processes. The parts are fabricated using different materials including wax, PZT, silicone nitride, and 17-4PH stainless steel powders for the SFF hardware (Langrana et al, 2000, Qiu et al, 1999, Danforth et al, 1998) and Ciba-Geigy SL-resin for SLA hardware (Higgins and Langrana, 1998, Higgins and Langrana 1999). The components such as turbine blades, actuators, and fixtures have been designed, simulated and fabricated. The properties of parts have been and are being quantified in terms of accuracy and quality.

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