Flows number

Flow models Flow number FLOWPACK Flow patterns Flow-sheet models FlowSorb 2300 FLOWIRAN... 

A general flow map of different hydrodynamic conditions (Fig. 23) consists of regions of flooding, dispersion, and recirculation on a plot of N vs for a Rushton turbine. For a low viscosity aqueous/air system, the gas flow numbers for the three conditions are given hy FI = 30Fr[D/TY for flooding, = 0.2Fr° (F/r)° for complete dispersion, and =13FF D/TY for recirculation. 

This is the basis for establishing the condition or type of fluid flow in a pipe. Reynolds numbers below 2000 to 2100 are usually considered to define laminar or thscous flow numbers from 2000 to 3000-4000 to define a transition region of peculiar flow, and numbers above 4000 to define a state of turbulent flow. Reference to Figure 2-3 and Figure 2-11 will identify these regions, and the friction factors associated with them [2]. 

This is probably the most important dimensionless group used to represent the actual flow during mixing in a vessel. Flow Number, Nq (or pumping number) ... 

R, = Reynolds number = No = d np/H Nqd = discharge flow number = qu/nd p - pressure qq = discharge flow rate ejq = mixing time... 

Mixing concepts, fundamentals, 297 Actual motor horsepower, 307 Axial flow, 291 Baffle diagrams, 318 Baffles, 311 Calculations, 297 Characteristic curves, 306 Draft lubes, 309, 312, 313 Entrainment, 309 Flow number, 298 Flow patterns, 309-313 Flow, 298... 

Note The respective impellers used are a classical Rushton turbine (DT), a hydrofoil impeller (A315) manufactured by Lightnin, and a Pitched Blade impeller (PBT). The cases 1 through 4 all relate to a superficial gas rate of 3.6mm/s only, with impeller speeds varying between 5 and 10/s (gas flow numbers between 0.01 and 0.02) cases 2 and 3 differ in sparger size and position. 

In comparison with Bakker and Van den Akker (1994b) and Venneker et al. (2002), Khopkar et al. (2005) applied a more sophisticated two-fluid approach including a standard k-e turbulence model. Using the incorrect snapshot approach due to Ranade (2002), their simulation results (for gas flow numbers being 4 times higher than those of Bakker and Van den Akker, 1994b) still exhibit major discrepancies with respect to experimental data. One of the... 

Fig. 15. Comparison of simulated and experimental gas hold-up distribution in a horizontal plane 10 cm above the bottom of the vessel. The gas flow number amounts to 0.084. Reproduced with permission from Khopkar et al. (2005).

Various correlations for mean droplet size generated using pressure-swirl and fan spray atomizers are summarized in Tables 4.4 and 4.5, respectively. In the correlations for pressure-swirl data, FN is the Flow number defined as FN = ml/APlpl) )5, l0 and d0 are the length and diameter of final orifice, respectively, ls and ds are the length and diameter of swirl chamber, respectively, Ap is the total inlet ports area, /yds the film thickness in final orifice, 6 is the half of spray cone angle, and Weyis the Weber number estimated with film... 

SMD = 10-3 (7(6.1 l+0.32xl05FAfp 5 -e xlO APi 5 +1.89x1 0 6APL) Derived from experimental data for 25 different fuels using 6 different simplex nozzles of large Flow numbers Wef>10 Strong effect of t7 no effect of Pl Discrepant with other data Kennedy [445]... 

The capacity of a nozzle is conveniently described by the flow number, FN a dimensional constant defined by ... 

Figure 10.7. Flow number as a function of impeller Reynolds number for a pitched blade turbine with AE = 1.37. D/T is the ratio of impeller and tank diameters. [Dickey, 1984, 12, 7 Chem. Eng., 102-110 26 Apr. 1976)].

At least partly because of its lower density and viscosity, the power to drive a mixture of gas and liquid is less than that to drive a liquid. Figure 10.11(a) is a correlation of this effect, and other data at low values of the flow number Q/Nd3 are on Figure 10.11(b). The latter data for Newtonian fluids are correlated by the equation... 

Figure 8. Location map of sampled lava flows on Mauna Loa. Numbers on the map correspond to flow numbers in Table 1 (Sahagian et al. 2002b).

The flow parameter A is often referred to as the flow number and is defined by A =. When A = 0.5 one... 

---