Flow of Liquid in the Pores

A pressure drop, VP, along the pores leads to liquid flow. The mass flux in the pores of the green body due to liquid flow is given by Darcy s law  

When the pores in the green body are partially filled, capillary pressure will also create a pressure driving force if the radius of curvature at one end of the pore is different than the other. As a result, flow will he induced from the highest pressure corresponding to the lowest radius of curvature to the lowest pressure corresponding to the highest radius 

FIGURE 14A Compressive stress inside a ceramic green body due to the presence of a polymer after it is dried of solvent. 

In three dimensions, these simultaneous differential equations are very complex and require numerical solution. For this reason, we will discuss simple geometries in the balance of this chapter with only one rate determining step. 

By considering the previous equations, we can see that there are four steps in the drying of ceramic green bodies  

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