Thermal model freeboard

Various models for the rotary kiln (Barr et al., 1989 Sass, 1967 Tscheng and Watkinson, 1978 and others) have the capability of predicting average conditions within both the bed and the freeboard as functions of axial position. The thermal component of these one-dimensional models can be derived by considering the transverse slice (Figure 8.7a), which divides the section into separate control volumes of freeboard gas and bed material. Under steady state conditions energy conservation for any control volume requires that... 

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