Process Simulation

Biomass and Bioenergy Research Group (BBRG) uses COMSOL Multiphysics to simulate the process. The simulation research includes the following fields:

  • Computational fluid dynamics (CFD) in various geometries
  • Solid particle flow in unit operations using discrete element method (DEM)
  • Heat transfer analysis
  • Moisture transfer between the solid particles and environment
  • Reaction simulation of solid particles in unit operations

COMSOL Multiphysics is a powerful interactive environment to simulate the multiphysics scientific and engineering problems based on partial differential equations (PDEs). Partial differential equations (PDEs) form the basis for the laws of science and provide the foundation for modeling a wide range of scientific and engineering phenomena. Many real-world applications involve simultaneous couplings in a system of PDEs – multiphysics. COMSOL Multiphysics uses the “Finite Element Method” (FEM) to solve the mathematical PDE equations. FEM converts al equation to their “weak” form that facilitates and accelerates the solving process. This conversion is a part of the solution technique rather than part of the modeling process and its details would not be explained in the current document.

Some examples of the conducted simulation projects are listed as follow:

  • Simulation of air flow in rotary drum dryer:



Velocity distribution of air inside the rotating drum.


  • Simulation of solid biomass particles in rotary drum dryer:


Movement of solid biomass particles along the drum length for a step injection of 10,000 particles with a diameter of 30 mm.


  • Simulation of residence time distribution (RTD) of solid particles in unit operations:

Injecting N number of particles at drum inlet at time zero (t=0). The model monitors and counts the particles at the drum outlet.

Time distribution of particles exiting the drum outlet.


  • Simulation of heat and moisture exchange of wood pellet in storage and shipping

It is still an ongoing project. The results will be published in the close future.