Determination of the Internal Film Coefficient

By grouping the terms, the equation can be solved for h the heat transfer coefficient of the reaction mass. This can be written as a function of the technical data of the reactor and the physico-chemical properties of the reaction mass  

Thus for a given reaction mass, the heat transfer coefficient of the internal film can be influenced by the stirrer speed and its diameter. The value of the equipment constant (z) can be calculated using the geometric characteristics of the reactor. The value of material constant for heat transfer (y) can either be calculated from the physical properties of the reactor contents-as far as they are known-or measured by the method of the Wilson plot in a reaction calorimeter [4, 5]. This parameter is independent of the geometry or size of the reactor. Thus, it can be determined at laboratory scale and used at industrial scale. The Wilson plot determines the overall heat transfer coefficient as a function of the agitator revolution speed in a reaction calorimeter  

The value of z, characterizing the internal part of the equipment factor, can be calculated using the geometric characteristics of the reactor. Some typical values of the agitator constant are given in Table 9.4 [2], 

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