Inlet geometry

The void fraction data obtained in micro-channels and conventional size channels showed significant differences depending on the channel cross-section and inlet geometry. For the micro-channel with a diameter of 100 pm, the effects of the inlet geometry and gas-liquid mixing method on the void fraction were seen to be quite strong, while the conventional size channels have shown a much smaller effect of inlet geometry on the void fraction. 

Thus, similar void fraction data can be obtained in micro-channels and conventional size channels, but the micro-channel void fraction can be sensitive to the inlet geometry and deviate significantly from the Armand correlation. 

For a micro-channel connected to a 100 pm T-junction the Lockhart-Martinelli model correlated well with the data, however, different C-values were needed to correlate well with all the data for the conventional size channels. In contrast, when the 100 pm micro-channel was connected to a reducing inlet section, the data could be fit by a single value of C = 0.24, and no mass velocity effect could be observed. When the T-junction diameter was increased to 500 pm, the best-fit C-value for the 100 pm micro-channel again dropped to a value of 0.24. Thus, as in the void fraction data, the friction pressure drop data in micro-channels and conventional size channels are similar, but for micro-channels, significantly different data can be obtained depending on the inlet geometry. 

The micro-channels are sensitive not only to inlet geometry but also to the method of gas-liquid injection. 

The sampling operation involves collection of an aerosol sample that is representative of the particle size distribution and concentration of the sampled atmosphere. The efficiency of particle transport and collection operations are dependent on the particle size, sampling velocity, the geometry of the sampling apparatus and the properties of the collection medium. In the present work, a 37 mm diameter membrane filter (0.3 ym pore size) is the primary collection medium under evaluation. The filter is housed in a standard filter cassette and effects of filter-holder inlet geometry are also being investigated. 

With the application of an enthalpy enhanced Three-Environment Model, the progress of the reactor inlet temperature belonging to the event of extinction as a function of the fuel mass fraction of the waste water could be theoretically supported. Correspondence between theoretical and experimental results is satisfactory. The deviation of the extinction line from a flame temperature isotherm appeared to be due to a Lewis number greater than one. If the Lewis number could be lowered, the required fuel mass fraction is supposed to decrease. Experiments with different kinds of fuel as well as modified burner and inlet geometries will either support these theories or give evidence to the contrary. 

Fig. 46. Dependence of axial voidage profile on inlet geometry and operating conditions— inlet (4) (after Xia and Tung, 1989).

The isothermal friction coefficients for the three inlet types showed that the range of the Reynolds number values at which transition flow exists is strongly inlet-geometry dependent. Furthermore, healing caused an increase in the laminar and turbulent friction coefficients and an increase in the lower and upper limits of the isothermal transition regime boundaries. The friction coefficient transition Reynolds number ranges for the isothermal and nonisotliermal (three different heating rates) and the three different inlets used in their study are summarized in Table 8-6. 

Fig. 3.8 Comparison of different inlet geometries for large-scale columns. (Reproduced from Pelz et al. 1998.)...

Use VNT variable nozzle turbine inlet geometry to improve performance across the desired flow range. 

It is difficult to state whether the tray inlet or outlet geometry has a greater influence on liquid distribution between the passes. Some simulator tests (384) imply that at low liquid loads (1 to 2 gpm per inch of outlet weir), tray inlet geometry would be far more important. It is uncertain whether this con-... 

Langrish, T. A. G. and Zbicinski, I. 1994. The effect of air inlet geometry and spray cone angle on the wall deposition rate in spray dryers. Trans. I. Chem. E. 72 420-430. 

Ganippa, L. C., Andersson, S., and Chomiak J., Combustion Characteristics of Diesel Sprays from Equivalent Nozzles with Sharp and Rounded Inlet Geometries, Combust. Sci. Technol., vol. 175, 2003, pp. 1015-1032. 

Lecleic, A., Philippe, R., Houzelot, V., Schweich, D., de Bellefon, C. (2010). Gas-liquid Taylor flow in square micro-chaimels New inlet geometries and interfaeial area tuning. Chemical Engineering Journal, 165, 290-300. 

Electrokinetic/Electrohydrodynamic Flow Instability, Fig. 5 (a) Schematic of the three-inlet geometry with electrodes and instability mixing. The channel height is 30 (tm, and the electrode to electrode spacing is 75 pm. (b) A stable flow in the absence of an electric field, (c) The disruption of flow after a 41 Vrms potential (initial applied field Eo = 8.2-10 V/m) is applied at 250 kHz to the electrodes, (d) EHD instability at 44 Vr s (initial applied field Eo = 8.8-10 V/m), 700 KHz. (e) Dispersion of the... 

Figure1.5 Flow patterns, (a) The most common flow patterns are bubbly flow, segmented flow and annular flow [79], (b) A flow map, indicating the ranges of gas and liquid velocity for which the various flow patterns are observed in a given device [80], These flow maps have to be used with care, as the pattern is not determined by velocities alone, such as wettability, channel geometry and inlet geometry (c-e). (c) Impact of wetting on observed flow patterns for a...

Different approaches can be followed to achieve flow equipartition. If the channels of one flow path of the reactor cover the entire length of the plate stack (similar to monolithic reactors), all channels of all plates of this flow path have a common distribution chamber. Alternatively, the flow between the channels of an individual plate is distributed in a relatively wide inlet region and a second flow chamber ensures the distribution over the different plates. In practical systems, the introduction of distribution grids is frequently required to ensure flow equipartition, as shown in Figure 7.1a [6]. Alternatively, a trumpet-shaped inlet geometry could be used as described by O Connell et al. [7] (see Figure 7.1b). 

Since the inlet pressure drop, is strongly dependent on the behavior of the melt a change in the inlet geometry would be expected to influence the pressure drop as well as the elastic and shearing strains. 

Figure 5 shows the data for both geometries plotted as log F against log Re for an 80mm axial length cylinder. It can be seen that changing the inlet geometry had no discernable effect on the rotor torque. 

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