Frossling correlation

Because reaction is assumed to occur instantaneously on the external surface of the pellet, Caj = 0. Also, Ca , is given as 1 mol/dm, The mass transfer coefficient for single spheres is calculated from the Frossling correlation ... 

Case 2 Shear between Particles and the Fluid If the particles are sheared by the fluid motion, one can neglect the 2 in the Frossling correlation between the Slherwood number and Reynolds number, and... 

Keywords Dufour effect Evaporation Frossling correlation Heat transfer Fatent heat Mass transfer Nusselt number Ranz-Marshall correlation Soret effect Stefan flow... 

Although some controversy exists on the correlation of Sherwood Number applicable to fluidized beds, well-defined combustion experiments support the use of the Ranz and Marshall (35) or Frossling (36) correlation with an approximate correction of mf to allow for the obstruction to diffusion by the inert particles surrounding the burning char particles (37). Thus... 

The parameters bo, at, and Pi are determined from experimental data. One common correlation is the Frossling/Ranz-Marshall correlation. 

Based on Frosslings development, Ranz and Marshall [102] came to the well established conclusion that the heat transfer correlation can be expressed in an analogous manner ... 

The subject of mass transfer from solid spheres has recently been examined by Keey and Glen [11], who maintained that the exponent of the Reynolds number in an equation of the Frossling type should increase with increasing Reynolds number due to the changing importance of wake transfer with Reynolds number and due to the onset of turbulence in the boundary layer. Keey and Glen recommended a different correlation for each Reynolds number region. 

The reader may find the number of correlations presented here for the mass transfer coefficients somewhat confusing. It is to be stressed that the expressions proposed by Frossling, Rantz and Marshall, and Rowe and Claxton give virtually identical results for the range of Reynolds and Schmidt numbers usually encountered in gas-solid reaction systems of practical interest. Indeed the ""rate expressions"" for gas-solid mass transfer constitute an area where most investigators appear to be in quite good agreement. 

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