Hi,
I am quite new to CFDEM and am trying to model convection.
To test the Pisoscalar solver I tried making a very simple case with a single particle.
I made a single row of 9 square CFD cells and place the particle in cell 5 with symmetry boundary conditions on the walls and remove drag and gravity acting on the particle.
The particle is a sphere with diameter equal to the side of one CFD cell so its placed exactly in the middle of cell 5.
Now I set the inlet velocity to 0.0003 m/s with water as fluid and run the Pisoscalar solver.
I get the right voidfraction in cell 5 which would make me suspect I should get a velocity of inletvelocity/voidfraction in that CFD cell.
However the velocity is much lower than that 5e-4 m/s as apposed to 6.25e-4 m/s.
Now I get the idea that the effect of the void fraction is spread around to the CFD cells above and below the particle since the velocity there is also higher.
However this means the velocity around the particle gets underestimated which in turn leads to a low heat-transfer coefficient.
Now my question is why is the velocity that the solver calculates in the CFD cell where the particle is not equal to inletvelocity/voidfraction?
And if anyone has any idea how to fix the model to arrive at the right velocity