Weber’s number

Processes of breakage and coalescence can be controlled. If we add demulsifier to the emulsion, it will be adsorbed at the drop surface, reducing the surface tension S and thus increasing Weber s number. At a certain demulsifier concentration, Weber s number exceeds the critical value and the drop splits. On the other hand, we can increase the collision frequency and coalescence rate of drops by... 

Miesse [49] predicted a formula for the D0.999, also known as the D ax for plain orifice nozzles. The equation was derived using second hand data and best-fitting it. The Dmax is related to both the Weber s number and the Reynolds number, as well as the exit orifice diameter. Weber s number is said to be less significant than Reynolds number. To observe this, the equation has been plotted in Fig. 24.32 as a function of both Weber s and Reynolds number. 

Fig. 24.32 Equation 24.5.vii plotted against (a) Weber s number, (b) Reynolds numbers, at different values of do...

Weber numbers Weber s law Web formation Web knitting Web offset inks Webster hardness gauge Weed killers... 

Weber S (2009) Spatio-temporal covariation of urban particle number concentration and ambient noise. Atmos Environ 43 5518-5525... 

These findings suggest that at least one prediction of a compressed linear representation of space, time, and number is satisfied. In all three cases, estimations of magnitude obey Weber s law by showing that error increases in proportion to the magnitude estimated. 

Orzechowski derived two more correlations, one for kerosene 24.7.x, and the other for a water-glycerin mixture 24.7.xi. The correlations are said to be a functirm of film thickness, Weber number and Ohnesorge s number. The effect of film thickness and Weber number remains unchanged on both liquids. The difference arises in Ohnesorge s number, where the exponent is slightly lower for kerosene. Figure 24.46 shows a comparison of the two equations, using t = 0.1 nun. 

In their analysis, however, they neglected the surface tension and the diffusivity. As has already been pointed out, the volumetric mass-transfer coefficient is a function of the interfacial area, which will be strongly affected by the surface tension. The mass-transfer coefficient per unit area will be a function of the diffusivity. The omission of these two important factors, surface tension and diffusivity, even though they were held constant in Pavlu-shenko s work, can result in changes in the values of the exponents in Eq. (48). For example, the omission of the surface tension would eliminate the Weber number, and the omission of the diffusivity eliminates the Schmidt number. Since these numbers include variables that already appear in Eq. (48), the groups in this equation that also contain these same variables could end up with different values for the exponents. 

Weber number Pe L We = -s a inertial force surface-tension force 8 10-2 2 10-2 Relevant for bubble (droplet) flows. Length scale bubble diameter... 

Pattern transition in horizontal adiabatic flow. An accurate analysis of pattern transitions on the basis of prevailing force(s) with flows in horizontal channels was performed and reported by Taitel and Dukler (1976b). In addition to the Froude and Weber numbers, other dimensionless groups used are... 

Drops may break up after being entrained in the vapor core. Vapor is generated continuously as a result of heat addition, leading to acceleration of the mixture and increased slip velocity. The sizes of drops formed in this way are characterized by the Weber number based on the slip velocity S. 

The simulation shown in Fig. 10 is an impact of a saturated water droplet of 2.3 mm in diameter onto a surface of 400°C with an impact velocity of 65 cm/s, corresponding to a Weber number of 15. This simulation and all others presented in this study are conducted on uniform meshes (Ax — Ay — Az = A). The mesh resolution of the simulation shown in Fig. 10 was 0.08 mm in grid size, although different resolutions are also tested and the results are compared in Figs. 11 and 12. The average time-step in this case is around 5 ps. It takes 4000 iterations to simulate a real time of 20 ms of the impact process. The simulation... 

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