Numerical simulation of gas flow past scale model of hypersonic vehicle in wind tunnel

In this work, the fluid dynamic and thermal behavior of steel was analyzed during argon gas stirring in a 140-t refining ladle. The Eulerian multiphase mathematical model was used in conjunction with the discrete ordinates (DO) thermal radiation model in a steel-slag-argon system. The model was validated by particle image velocimetry (PIV) and the analysis of the opening of the oil layer in a physical scale model. The effect of Al2O3 and Mg-C as a refractory in the walls was studied, and the Ranz-Marshall and Tomiyama models were compared to determine the heat exchange coefficient. The results indicated that there were no significant differences between these heat exchange models; likewise, the radiation heat transfer model adequately simulated the thermal behavior according to plant measurements, finding a thermal homogenization time of the steel of 2.5 min for a gas flow of 0.45 Nm3·min−1. Finally, both types of refractory kept the temperature of the steel within the ranges recommended in the plant; however, the use of Al2O3 had better heat retention, which would favor refining operations.

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Investigation on influences of loose gas on gas-solid flows in a circulating fluidized bed (CFB) reactor using full-loop numerical simulation

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2020-0119 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Pengju Huo ◽

Xiaohong Li ◽

Yang Liu ◽

Haiying Qi

Keyword(s):

Numerical Simulation ◽

Flow Rate ◽

Gas Flow ◽

Circulating Fluidized Bed ◽

Separation Efficiency ◽

Circulation Rate ◽

Solid Mass ◽

Gas Flow Rate ◽

Gas Leakage ◽

Mass Circulation

AbstractThe influences of loose gas on gas-solid flows in a large-scale circulating fluidized bed (CFB) gasification reactor were investigated using full-loop numerical simulation. The two-fluid model was coupled with the QC-energy minimization in multi-scale theory (EMMS) gas-solid drag model to simulate the fluidization in the CFB reactor. Effects of the loose gas flow rate, Q, on the solid mass circulation rate and the cyclone separation efficiency were analyzed. The study found different effects depending on Q: First, the particles in the loop seal and the standpipe tended to become more densely packed with decreasing loose gas flow rate, leading to the reduction in the overall circulation rate. The minimum Q that can affect the solid mass circulation rate is about 2.5% of the fluidized gas flow rate. Second, the sealing gas capability of the particles is enhanced as the loose gas flow rate decreases, which reduces the gas leakage into the cyclones and improves their separation efficiency. The best loose gas flow rates are equal to 2.5% of the fluidized gas flow rate at the various supply positions. In addition, the cyclone separation efficiency is correlated with the gas leakage to predict the separation efficiency during industrial operation.

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Investigation of the Time Dependence of Wind-Induced Aeroelastic Response on a Scale Model of a High-Rise Building

Applied Sciences ◽

10.3390/app11083315 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3315

Author(s):

Fabio Rizzo

Keyword(s):

Wind Tunnel ◽

Time Dependence ◽

Wind Tunnel Test ◽

Structural Response ◽

Cumulative Distribution ◽

Scale Model ◽

Acquisition Time ◽

Test Results ◽

High Rise ◽

High Rise Building

Experimental wind tunnel test results are affected by acquisition times because extreme pressure peak statistics depend on the length of acquisition records. This is also true for dynamic tests on aeroelastic models where the structural response of the scale model is affected by aerodynamic damping and by random vortex shedding. This paper investigates the acquisition time dependence of linear transformation through singular value decomposition (SVD) and its correlation with floor accelerometric signals acquired during wind tunnel aeroelastic testing of a scale model high-rise building. Particular attention was given to the variability of eigenvectors, singular values and the correlation coefficient for two wind angles and thirteen different wind velocities. The cumulative distribution function of empirical magnitudes was fitted with numerical cumulative density function (CDF). Kolmogorov–Smirnov test results are also discussed.

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