Inlet configurations

Mass concentration units for ambient measurements are mass (/xg) per unit volume (m ). Size classification involves the use of specially designed inlet configurations, e.g., PMjq sampling. To determine mass concentration, all the particles are removed from a known volume of air and their total mass is measured. This removal is accomplished by two techniques, filtration and impaction, described in Chapter 13. Mass measurements are made by pre-and postweighing of filters or impaction surfaces. To account for the absorption of water vapor, the filters are generally equilibrated at standard conditions T = 20°C and 50% relative humidity). 

Inlet configuration Outlet configuration Coefficient of entry, C,... 

End-suction and multi-stage pumps with in-line impellers are prone to excessive axial thrusting. In the end-suction pump, the centerline axial inlet configuration is the primary source of thrust. Restrictions in the suction piping, or low suction pressures, create a strong imbalance that forces the rotating element toward the inlet. 

Three generic forms of cyclone can be characterized by their inlet configurations as illustrated in Fig. 11. At equal gas inlet or gas outlet velocities, the tangential generally yields the highest collection efficiency. At very high inlet particle loadings, differences between the three forms... 

Miniature handheld detection system Battery powered, vapor sampling Estimated operating time -4 hours Results in 1-3 seconds Version 1 —lab prototype Version 2—planned improvements Optimize performance Data acquisition and data analysis software Embedded processor and LCD New inlet configuration... 

A globe valve (which has a typically high pressure drop) mounted under an SRV can in fact only be suitable for liquid thermal relief due to the very low lift of the SRV and the very small amount of product discharged per relief cycle. Other valves may be used under a PRV as long as they are full bore and can be locked open. In Figure 6.2, some L/D values are given for some traditional valve inlet configurations. 

The right one is less obvious, but the method of penetration and inlet configuration within the vessel can cause significant inlet pressure losses, as is demonstrated in Figure 6.6. 

Chaotic particle motion can occur for two-dimensional velocity fields which are time dependent and for three-dimensional velocity fields [46], For induction of such complex fields, one option is to guide the flow close to structured surfaces, e.g. placed on a channel s bottom, starting from a T-type flow inlet configurations. 

Since the dead volume VM is rather large in prep columns, the size of the sample volume can also be quite large and may require a pump for filling the sample loops in the sample valve. For maximum efficiency, the sample should be spread out over the entire column, and a study of this effect has recommended special inlet configurations.80... 

The results presented so far in this section correspond to the regime of fully developed riser flow. Kuipers and van Swaaij (1996) applied the KTGF-based model developed by Nieuwland et al. (1996b,c) to study the effect of riser inlet configuration on the (developing) flow in CFB riser tubes and found that the differences in computed radial profiles of hydrodynamic key variables (i.e., gas and solids phase mass fluxes) rapidly disappear with increasing elevation in the riser tube. 

Kuipers, J. A. M., and van Swaaij, W. P. M., Developing flow in CFB-risers A computational study of the effect of riser inlet configuration on flow stmcture development. Workshop II on Modelling and Control of Fluidizied Bed Systems, CFB-5, Beijing (1996). 

Fully developed friction coeffTicients for three different inlet configuration and beat fluxes (filled symbols designate the start and end of the transition region for each inlet. 

Figure 8-34 shows ihe influence of inlet configuration on the beginning and end of the isothermal fully developed friction coefficients in the transition region. 

A tube v/ith a bell-mouth inlet configuration is subjected to 8 kW/m uniform vrall heat flux. The tube has an inside diameter of 0.0158 m and a flov/ rate of 1.32 X 10 " m%. The liquid flowing inside the tube is ethylene glycol-P distilled v/ater mixture with a mass fraction of 0,34. The properties of the ethylene glycol-distilled water mixture at the location of interest are Pr = 11,6, V- 1.39 X 10 m /s and 1.14. Determine the fully developed... 

Tlie physical properties appearing in the dimensionless numbers Nu, Re, Pr, and Or all are evaluated at the bulk fluid temperature T. The values of the empirical con.slanls a, b, and c in Eq. 8-83 depend on the inlet configuration and are given in Table 8-7. The viscosity ratio accounts for the temperature effect on the process. Tlte range of application of the heat transfer method based on their database of 1290 points (441 points for re-entrant... 

Ethylene glycol-distilled water mixture with a rhass fraction of 0.6 and a flow I rate of 2.5 x 10 m /s flows inside a tube with an inside diameter of 0.0158 m subjected to uniform wall heat flux. For this flow, determine the Nusselt number at the location x/D = 90 if the inlet configuration of the tube ] iS (a) re-entrant, (b) square-edged, and (c) beli-mouth. At this location, the local Grashof number is Gr = 51,770. The properties of ethylene glycol-distillcd water mixture at the location of interest are Pr = 29.2, v = 3.12 x 10 m% and P(//is = 1.77.. 

Therefore, the flow regime is in the transition region for all three inlet configurations (thus use the information given in Table 8-8 v/ith x/D - 90) and therefore Eq. 8-83 should he used v/ith the constants a, b, c found in Table 8-7. However, NU, ,and Nun, are the inputs to Eq. 8-83 and they need to be evaluated first from Eqs. 8-84 and 8-85, respectively. It should be mentioned that the correlations for Nui and Nu, rt, have no inlet dependency. 

A. J. Ghajar and K. F. Madon. Pressure Drop Measurements in the Dramsidon Region for a Circular Tlibe with Three Different Inlet Configurations." Experimental Thermal and Fluid Science, Vol. 5 (1992), pp. 129-135. 

Rotatable units offering various options for vapor sources, reaction vessesls, vacuum stations and ligand inlet configurations are offered commercially.(17,18,27) The Planar apparatus(17) utilizes a variable pitch, 5"-45"-horizontal 10 L glass flask which accepts single, twin and mixed vapor sources like those provided for its static models. The hybridized resistive/electron beam furnace... 

Generally, the duct inlet configuration and surface roughness have significant effects on the value of Rec. Other factors, such as noise, vibration, and flow pulsation, affect ReCTii as well. Caution should be taken to choose Recn, for the particular application. On the other hand, flow and heat transfer characteristics are difficult to predict in transition flow. The reader is encouraged to consult the literature for the cases not mentioned in this chapter. 

Turbulent Flow. The Nusselt numbers for simultaneously developing turbulent flow are practically the same as the Nusselt numbers for the thermally developing turbulent flow [46]. However, the Nusselt numbers for simultaneously developing flow are sensitive to the passage inlet configuration. 

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