Reynolds number calculation

Droplet trajectories for limiting cases can be calculated by combining the equations of motion with the droplet evaporation rate equation to assess the likelihood that drops exit or hit the wall before evaporating. It is best to consider upper bound droplet sizes in addition to the mean size in these calculations. If desired, an instantaneous value for the evaporation rate constant may also be used based on an instantaneous Reynolds number calculated not from the terminal velocity but at a resultant velocity. In this case, equation 37 is substituted for equation 32 ... 

However, one should be cautious when comparing the Reynolds number from regular Karman vortex streets with the Reynolds number calculated from factual situations in clean benches as the airflow from behind an obstacle is usually not the typically formed Karman vortex street predicted for an indefinitely long circular cylinder. The wake situations during actual conditions often seem to have a three-dimensional stmcnire. 

It was shown that a normalized version of the two-phase friction factor, CfTpl CfQ, is uniquely related to X. The normalizing friction factor, CfQ, is calculated from single-phase friction factor correlations using a Reynolds number calculated as if both phases flow as liquid,... 

Reynolds numbers calculated for the in vivo hydrodynamics are considerably lower than those of the corresponding in vitro numbers, both for bulk and particle-liquid Reynolds numbers. Remarkably, bulk Reynolds numbers in vivo appear to have about the same magnitude as particle-liquid Reynolds numbers characterizing the flow at the particle surface in vitro using the paddle apparatus. In other words, it appears that hydrodynamics per se play a relatively minor role in vivo compared to the in vitro dissolution. This can be attributed to physiological co-factors that greatly affect the overall dissolution in vivo but are not important in vitro (e.g., absorption and secretion processes, change of MMC phases,... 

CRE is the Boucher [3] Reynolds number calculation to derive a drag coefficient, CD. The CD factor is calculated in the program by a curve-fit equation as shown. The velocity, called the terminal droplet velocity, is calculated as the variable VT, also called the dropout velocity or the settling velocity. All three terms refer to this same variable. 

One of the two equations is chosen in the Vessize program by using a Reynolds number test. If the Reynolds number, CRE, is less than 0.3, then Eq. (4.10) is used. It is important to note here that all cases of a water particle settling or a gas particle rising in the oil phase should have a Reynolds number less than 0.3. Why should this be Please consider the Reynolds number calculated in the standard Reynolds number equation from Fig. 4.7, Eq. (4.11) ... 

One of the main concerns is that using the torque value that the imit is reporting instead of the dynamic viscosity for calculation of Reynolds numbers renders the latter to become dimensional. Therefore, the Reynolds number calculated from torque rheometer data is referred to as pseudo-Reynolds dimensional number. Because of the fact that torque was shown to be proportional to a kinematic (rather than dynamic)... 

The Reynolds numbers calculated according to (3.281) barely deviate from those calculated using a different equation communicated by Martin [3.43], but reproduce the relationship Res(Ar), which is gained by inserting the accurate resistance law (3.279) from Brauer into (3.278), somewhat better. The maximum... 

In axial flow past disks, which are the limit cases of axisymmetric bodies of small length, the drag coefficients are given in [94] for the entire range of Reynolds numbers calculated with respect to the radius. These formulas approximate numerical results and experimental data ... 

FIGURE 51.15 Relationship between critical Reynolds number at incipient spouting and Reynolds number calculated for sedimentation velocity RCj. 

Reynolds number calculations rule out the possibility of a change from laminar to turbulent flow in the present studies. The shear rate magnitudes and flow regime favor the applicability of Darcy s law. 

The Reynolds number calculated at the bulk fluid temperature of 477.6 K is Dvp 6.0254(7.62X1.509)... 

To achieve a defined blending result, it is a prerequisite that the entire volume of the vessel is involved in the laminar flow. The Reynolds number calculated with the impeller diameter represents only an inadequate description of the flow conditions in the entire vessel, particularly in the case of impellers with small zones of agitation. The dimensionless blend time in nO for these impellers therefore starts to increase at a point where the reducing Reynolds number theoretically still indicates turbulent flow (see Figpre 13.6, propeller D/T = 0.3). 

The fin plates are shaped from 0.15 to 0.6 mm thick aluminium sheets by periodical distortion. The fin height, i.e. the clearance between the neighbouring partition plates, ranges between 3.8 and 12 mm. The distortions form channels with diameters ranging between 1.2 and 4.5 mm. The Reynolds number calculated on the basis of this diameter lies between about 500-10 000, i.e. the flow is in the transition range between laminar and turbulent In order to improve the turbulence and thus the heat transfer, additional obstacles are installed. To this end, fins are either perforated or are serrated and periodically displaced against each other with a certain clearance. 

Because of the change in the Reynolds number, calculated values of kg change however, because of the relationship between two other dimensionless groups, the Prandtl and Schmidt numbers, assume the kg/h ratio is constant at 9.0 x 10 cm K/cal. 

The concept of a porous medium supposes that the grains forming the porous medium are small. This notion is only meaningful in the context of a flow inside the porous medium. Small signifies that the flow inside the porous medium is slow. The Reynolds number, calculated from the velocity of the flow inside the porous medium, the characteristic size of the pores and the kinematic viscosity of the fluid, should be sufficiently small for the flow inside the porous medium to be laminar. 

FIG. 17 The dependence of the a, parameter on the Reynolds number calculated numerically for the RIJ cell h /R = 1.6) the dashed line represents the high-Re fit [Eq. (106b)] the solid line represents the low-Re fit [Eq. (106a)] the dotted line shows the results for the sphere calculated from Eq. (96). 

Assume velocity V, and calculate Reynolds number. From Reynolds number, calculate the friction factor from the Moody diagram shown in Figure 2.2, otherwise it can be obtained from the above-mentioned equations. Calculate the pressure drop and then compare the calculated result with the given value of pressure drop which is 118 kPa in the question of the example. Repeat until the desired pressure drop is reached. Polymath software can be used instead (Figure 2.19). The calculated velocity is 5.29 m/s as shown in Figure 2.20. 

Resuspension velocities for one particular. slurry [117] in a f-in. gla.ss pipe are given in Table 4-11 together with the rheological pi operties [118] and the critical Reynolds number calculated with the resuspension velocity. ... 

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