A physically rigorous computational algorithm is developed and applied to calculate subcontinuum thermal transport in structures containing semiconductor-gas interfaces. The solution is based on a finite volume discretization of the Boltzmann equation for gas molecules in the gas phase and phonons in the semiconductor . A partial equilibrium is assumed between gas molecules and phonons at the i...

A bioreactor refers to any manufactured or engineered device that supports a biologically active environment. These kinds of reactors are designed to treat wastewater treatment. Volumetric mass transfer coefficient and the effect of superficial gas velocity, as the most important operational factor on hydrodynamics, in three-phase airlift reactors are investigated in this study. The experiments...

The design of furnaces and boilers for solid fuels is supported increasingly by powerful softwares and ever faster computers. A round-robin over the most important CFD (computational fluid mechanics) models and softwares currently available shows, however, that numerical procedures for particle/turbulence interactions are not (yet) very advanced. Particle/fluid interphase slip is considered, bu...

the michelsen stability and multiphase flash calculation by direct minimization of gibbs free energy of the system at constant temperature and pressure, was used for systems containing gas hydrates. the solid hydrate phase was treated as a solid solution. the fugacities of all components of the hydrate phase were calculated as a function of compositions by the rearranged model of van der waals ...

The Michelsen stability and multiphase flash calculation by direct minimization of Gibbs free energy of the system at constant temperature and pressure, was used for systems containing gas hydrates. The solid hydrate phase was treated as a solid solution. The fugacities of all components of the hydrate phase were calculated as a function of compositions by the rearranged model of van der Wa...

In this research, heat transfer of a poly Ethylene fluidized bed reactor without reaction were studied experimentally and computationally at different superficial gas velocities. A multifluid Eulerian computational model incorporating the kinetic theory for solid particles was developed and used to simulate the heat conducting gas–solid flows in a fluidized bed configuration. Momentum exchange ...

This paper gives an overview about the principles and the technologies used in solid-state gas sensors. These devices work by measuring a physical property changed by adsorption/desorption processes and chemical reactions on the surface of a sensing element, i.e. a solid-state film of a gas-sensitive material. Some of the most used types of solid state gas sensors are here described together wi...

In this work, we develop a self-consistent physical model of bubbles in a gas-solid 1 two-phase flow. Based on PR state equation, and a detailed specific heat ratio equation of bubbles, 2 we self-consistently evaluate kinetic equations of the bubbles on the basis of Ergun equation, 3 thermodynamic equation and kinetic equations. It is found that the specific heat ratio of bubbles in 4 such syst...

The occurrence of heterogeneous flow structures in gas-particle flows seriously affects the gas-solid contacting and transport processes in high-velocity gas-fluidized beds. Particles do not disperse uniformly in the flow but pass through the bed in a swarm of clusters. The so-called “core-annulus” structure in the radial direction and “S” shaped axial distribution of solids concentration chara...