Is the Sort effect included in the mass transfer equations in COMSOL software by default or does the user have to add the corresponding equation in the software?
COMSOL provides a dedicated example demonstrating how to model thermophoresis:
Thermophoresis Model: This tutorial predicts the size of a particle-free zone above a heated susceptor for different temperature gradients. It requires the Particle Tracing Module, the Heat Transfer Module, and one of the following: CFD Module, Microfluidics Module, or Plasma Module. The model setup involves defining the temperature field and calculating the resulting thermophoretic force acting on particles.