Velocity superficial density-weighted

To minimize the cost of recovering and recycling the solvent, contact the miiumum amount of liquid with the maximum amount of gas. For packings, this means the hquid loadings about 3 L/m s with high gas flow rates of superficial density-weighted velocity F-factor of 3.5 m/s (kg/m )°. ... 

Assume HTUog = 0.6 m with maximum packing height 12 m. Superficial gas velocity 1 m/s and/or superficial density-weighted velocity E-factor of 0.6 to 3.5 m/s (kg/m )°. Use 2.5-mm Pall rings or Tellerettes of metal or plastic. 

The superficial, density-weighted vapor velocity, k , is used to size the diameter of distillation columns, absorbers. Section 4. 8, gas-liquid separators or knock out pots, Section 5.1, and face velocity to demisters, Section 9.1. For convenience, values of k are given in Table 4.1 for different applications. 

Solid superficial velocity = solid mass flow rate divided by solid density, where solid mass flow rate=weight of solid per unit time divided by cross-sectional area of transport pipe. 

Flooding at the density ratio-weighted superficial vapor velocity, k factor, of 0.1 m/s. 

To model the measured transient foam displacements, equations 2 through 12 are rewritten in standard implicit-pressure, explicit-saturation (IMPES) finite difference form, with upstream weighting of the phase mobilities following standard reservoir simulation practice (10). Iteration of the nonlinear algebraic equations is by Newton s method. The three primitive unknowns are pressure, gas-phase saturation, and bubble density. Four boundary conditions are necessary because the differential mass balances are second order in pressure and first order in saturation and bubble concentration. The outlet pressure and the inlet superficial velocities of gas and liquid are fixed. No foam is injected, so Qh is set to zero in equation... 

An important characteristic of any fluidizable material is its minimum fluidization velocity, that is the superficial velocity needed to "lift the particles. It appears that, for fine particles, this is mostly determined by the viscosity of the fluid, and by the density difference between the solid and the fluid. That is so because the flow between the small particles, at these low flow rates, is e ssentially laminar. We can use eq. (4.36), replace Ap by the weight of the bed per unit area Ap (1 - e) g /, and neglect the turbulence term. The minimum fluidization velocity u, is then... 

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