Heat and Mass Transfer Coefficients for Flow around Catalyst Particles

2 Heat and Mass Transfer Coefficients for Flow around Catalyst Particles 

There are many correlations available for heat and mass transfer to particles. These are all have the Nusselt number Nu = adjk (or the Sherwood number Sh = kgd/D) as a function of the Reynolds number Re = udjv and the Prandtl number Pr = vl (Al pcp) (or the Schmidt number Sc = v/D). 

Here dp is a relevant length measure of the catalyst particle, such as its diameter, a and kg are the heat and the mass transfer coefficients to the particle, u is the average, characteristic velocity of the reaction medium with respect to the particle, and A, v, p and cp are the heat conductivity, kinematic viscosity, density and heat capacity of the reaction medium surrounding a particle, either a gas or a liquid. D is the molecular diffusion coefficient of the component transferred to the catalyst particle in the reaction medium. 

Gnielinski [3] derived a correlation for single particles, which represents all data measured with sufficient accuracy for technical applications  

In these equations Re, is the Reynolds number for a flow field in which both forced as well as free convection occurs  

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