Thermal Diffusion and Gravity Segregation in ID

Thermal diffusion and gravity segregation in 1D. The combined effect of thermal diffusion and gravity segregation in the ID vertical direction at steady state is governed by 0. Using Eq. (2.87) and dPjdz = —pg, one obtains 

When the temperature gradient is negligible, the last terra in Eq. (2.88) drops out, and since 

Equation (2.91) is the fugacity form of Eq. (2.19a) when the number of components is two. For a near-critical two-component fluid mixture (9x /9In/ilTTp is large, and therefore, dxi/dz) is also large (see the next section). 

Before we move on to study the effect of the temperature gradient on natural convection and thermal diffusion in hydrocarbon reservoirs, we will briefly discuss the thermal diffusion ratio, /ey. 

Thermal diffusion ratio, k-p. Thermal diffusion ratio, kp, is a measure of thermal diffusion. The sign of kp determines the direction of thermal diffusion. Another defined parameter for thermal diffusion is the thermal diffusion factor, a, which is defined as 

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