bubble column reactors are used in a wide variety of applications such as multiphase bioreactors, catalytic slurry reactors, and absorption processes. the superficial gas velocity-gas holdup relationship and transition point are two important parameters for characterizing the hydrodynamics of a bubble column reactor. in this study, systematic investigation of a nitrogen - water - glass beads bu...

In the present study, the influence of superficial gas velocity and fluid properties on gas holdup and liquid circulation velocity in a three-phase external loop airlift column using polystyrene (0.0036 m diameter and 1025.55 kg/m density) and nylon-6 (0.0035 m diameter and 1084.24 kg/m density) particles with aqueous solutions of alcohols (isoamyl alcohol and propanol) as liquids were investig...

In this paper we present the analytic solutions for two test problems involving two-fluid mixtures of dust and gas in an astrophysical context. The solutions provide a means of benchmarking numerical codes designed to simulate the non-linear dynamics of dusty gas. The first problem, DUSTYBOX, consists of two interpenetrating homogeneous fluids moving with relative velocity difference. We provid...

Effect of interparticle force on the hydrodynamics of gas-solid fluidized beds was investigated using the combined method of computational fluid dynamics and discrete element method (CFD-DEM). The cohesive force between particles was considered to follow the van der Waals equation form. The model was validated by experimental results from literature in terms of bed voidage distribution and Eule...

a linear superposition method was used for modeling the time history of the production blast vibrations and optimizing the blast sequence to reduce vibration levels in sar-cheshmeh copper mine, kerman, iran. a single-hole blast for modeling and two double-hole blasts with time delays of 25 and 65 ms between two holes for modeling validation were carried out. the generated vibrations were measur...

Near-future SZ surveys such as ACT, SPT, APEX, and Planck will soon find thousands of galaxy clusters. Multi-frequency arcminute-resolution SZ observations can, in principle, determine each cluster’s gas temperature (Te), bulk velocity (vpec), and optical depth (τ). However, the frequency bands and detector sensitivity employed by upcoming surveys will generally not be sufficient to disentangle...

While built on a sound physical foundation, isentropic, one-dimensional models generally used to analyze the dynamics of dilute two-phase (feed-powder particles suspended in a carrier gas) flow during the cold-gas dynamic-spray process, require the use of numerical procedures to obtain solutions for the governing equations. Numerical solutions, unfortunately, do not enable an easy establishment...

Near-future SZ surveys such as ACT, SPT, APEX, and Planck will soon find thousands of galaxy clusters. Multi-frequency arcminute-resolution SZ observations can, in principle, determine each cluster’s gas temperature (Te), bulk velocity (vpec), and optical depth (τ). However, the frequency bands and detector sensitivity employed by upcoming surveys will generally not be sufficient to disentangle...

Existence of gas-hydrates in the marine sediments elevates the velocity of seismic waves, whereas even a small amount of underlying free-gas decreases the seismic velocity considerably. These changes in velocities can be used for the assessment of gas-hydrates. The traveltime inversion is an effective method to derive a 2-D velocity structure from the seismic data. We have applied the method to...

A new analytical study performed to investigate the effect of the temperature difference between gas and particle in propagation of the spherical flames. The combustible system is containing uniformly distributed volatile fuel particles in an oxidizing gas (Air) mixture. The model includes evaporation of volatile matter of dust particles to known gaseous fuel (methane) and the single-stage reac...