Gases velocity distribution

Thermal structure of lean limit methane flame. Isotherms calculated from the measured gas velocity distribution. 

In the Lagrangian frame, droplet trajectories in the spray may be calculated using Thomas 2-D equations of motion for a sphere 5791 or the simplified forms)154 1561 The gas velocity distribution in the spray can be determined by either numerical modeling or direct experimental measurements. Using the uncoupled solution approach, many CFD software packages or Navier-Stokes solvers can be used to calculate the gas velocity distribution for various process parameters and atomizer geometries/configurations. On the other hand, somesimple expressions for the gas velocity distribution can be derived from... 

Yang Y.L, Gautam M, Mei J.S, Gas velocity distribution in a circulating fluidised bed riser, Powder Technology, 78,221 (1994)... 

Gas kinetic theory, for the purposes of this book, consists of the relationships defining the simple pressure, gas velocity distribution, mean free path and impinging flux of gases to the surface of a substrate, and other relevant theoretical relationships. These collective descriptions of the gases form a set of comprehensive theoretical understanding and representation for CVD processes. The following subsections briefly describe this constituent theory. 

Values of D and c are determined by the factors discussed in Chapter 2. The new quantity entering (3.1) is the gas velocity distribution, v, which is determined by the fluid mechanical regime. In some cases, v is obtained by solving the equations of fluid motion (Navier-Stokes equations) for which an extensive literature is available (Landau... 

For the heated vertical plate and horizontal cylinder, the flow results from natural convection. The stagnation configuration is a forced flow. In each case the flow is of the boimdai7 Kiyer type. Simple analytical solutions can be obtained when the thickness of the du.st-free space is much smaller than that of the boundary layer. In this case the gas velocity distribution can be approximated by the first term in an expansion in the distance norroal to the surface. Expressions for the thickness of the dust-free space for a heated vertical surface and a plane stagnation flow are derived below. 

Fibrous deep bed fillers can be modeled as a collection of single cylindrical fibers set normal to the Row of an aerosol. The removal efficiency for the single fibers cun be e.stimated from theory if the gas velocity distribution around the fibers (cylinders) is known. 

Unfortunately, the many time-dependent operating parameters (feed composition, flowrate, and temperature), the limited knowledge of the basic processes (kinetic rates, poisoning, gas velocity distribution, heat and mass transfer, etc.), and finally the possibility of steady state multiplicity, make modeling of the converter an overwhelming task. 

In the PSGA process, the selected ring-gas nozzle typically is composed of 20 circular inlets. The axis of the circular inlet is parallel to the centre line of the atomizer, that is the inclination angle is 0°. The diameter of each inlet at the nozzle exit section is 1.1 mm. Figure 18.20 presents the calculated gas velocity distributions without droplet injection under different atomization pressures (po)-... 

The absorber tower symmetrical reducing outlet provides a uniform velocity distribution at the front face of the horizontal mist eliminator. Experience has shown that poor flue gas velocity distribution can cause excessive mist carryover. The two-stage, triple-washed mist-eliminator system provides both a roughing chevron for capture of large drops of slurry and a finishing chevron to capture smaller drops of slurry and wash-water. Wash headers on both the lower and upper surface of the first stage mist eliminator and the lower surface... 

Thus, if design data of blades of an impeller are set, it is possible to count a gas velocity distribution at a flow its gas-dispersed stream. Knowing speeds of gas in various points of a gas stream, it is possible to define forces of an aerodynamic resistance on which mechanical trajectories of firm corpuscles in slot-hole channels depend. 

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