Transfer dimensionless

Zh Ratio of sensible heat removed from vapor to total heat transferred Dimensionless Dimensionless... 

N Number of overall transfer Dimensionless Dimensionless decanter ... 

For heat transfer the Fourier number is cct/a. The heat transfer analogs of the mass transfer dimensionless groups can be found by making the substitutions described in Chapter 1. 

Equation (4.36) provides a simple method for estimating an important heat transfer dimensionless group called the Prandtl number. Recall from general chemistry and thermodynamics that there are two types of molar heat capacities, C , and the constant pressure heat capacity, Cp. For an ideal gas, C = 3Cpl5. The Prandtl number is... 

Table 6.2 Relationships of the kinetic transfer dimensionless groups.

Jd = Chilton-Colburn j-factor for mass transfer, dimensionless... 

Dimensionless group Dimensionless group Dimensionless concentration Peclet number for mass transfer Peclet number for heat transfer Dimensionless temperature Dimensionless length Activation energy group Dimensionless time... 

Each of these is a ratio of a convective transfer rate to the corresponding diffusion rate of transfer. Dimensionless analysis indicates that, for fixed geometry and constant properties, the Nusselt number and the Sherwood number depend on the Reynolds number (forced convection), Rayleigh number (natural convection), flow characteristics, Prandtl number (heat transfer), and Schmidt number (mass transfer). 

StH Stanton number for heat transfer dimensionless. t tray spacing m. 

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