Jacob number

Cole R, Shulman HL (1966) Bubble growth rates at high Jacob numbers Int J Heat Mass Transfer 9 1377-1390... 

The forced fluid flow in heated micro-channels with a distinct evaporation front is considered. The effect of a number of dimensionless parameters such as the Peclet, Jacob numbers, and dimensionless heat flux, on the velocity, temperature and pressure within the liquid and vapor domains has been studied, and the parameters corresponding to the steady flow regime, as well as the domains of flow instability are delineated. An experiment was conducted and demonstrated that the flow in microchannels appear to have to distinct phase domains one for the liquid and the other for the vapor, with a short section of two-phase mixture between them. 

Two-phase flows in micro-channels with an evaporating meniscus, which separates the liquid and vapor regions, have been considered by Khrustalev and Faghri (1996) and Peles et al. (1998, 2000). In the latter a quasi-one-dimensional model was used to analyze the thermohydrodynamic characteristics of the flow in a heated capillary, with a distinct interface. This model takes into account the multi-stage character of the process, as well as the effect of capillary, friction and gravity forces on the flow development. The theoretical and experimental studies of the steady forced flow in a micro-channel with evaporating meniscus were carried out by Peles et al. (2001). These studies revealed the effect of a number of dimensionless parameters such as the Peclet and Jacob numbers, dimensionless heat transfer flux, etc., on the velocity, temperature and pressure distributions in the liquid and vapor regions. The structure of flow in heated micro-channels is determined by a number of factors the physical properties of fluid, its velocity, heat flux on... 

Qh being the longitudinal net enthalpy flow, >2 the enthalpy, flow across the two-phase interface, and Qk the conduction. In situations involving phase change, the Jacob number denoting the ratio of sensible heat to latent heat,... 

Figure 7.2.11. Dependence of the effective Jacob number for a vapor bubble, growing in a superheated aqueous solution of a polymer, on the parameter G. [Reprinted from Z.P. Shulman, and S.P. Levitsky, Int. J. Heat Mass Transfer, 39, 631, Copyright 1996, the reference 52, with permission from Elsevier Science]...

The role of diffusion-induced retardation increases with the bulk superheat. This reveals itself in reduction of the number Sn with a growth in AT (Figure 7.2.12). For solutions of polymers in volatile organic liquids, such as solvents, the effect is higher than in aqueous solutions. For concentrated solutions the difference between the effective AT and bulk AT superheats makes it practically impossible to increase substantially the rate of vapor bubble Figure 7.2.12. Effect of the solution bulk superheat growth by increasing the bulk superheat, on the Scriven and Jacob numbers. (-) - solution of Curves 5 and 5 clearly demonstrate this. They... 

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