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vbr_sagi March 19, 2010 15:54

Modeling Non-Premixed fuel burning in a cylindrical reactor
I am trying to model burning of solid fuel in air inside a cylindrical reactor. The geometry I created is two cylinders of diameters 1cm and 2cm respectively and of equal length 5 cm at the same origin. I filled the smaller cylinder with the fuel and the surrounding bigger cylinder with air. The boundaries specified for both the cylinders are:
1. Smaller cylinder:
The circular faces are given as walls and the third face as mass flow inlet
2. Bigger cylinder:
The circular faces are given as outflows and the third face is given as a wall.

I have set the boundary conditions as:
1. The outer wall has a heat input of ~9x10^6 W/m^3 and at an initial temperature of 800K
2. The mass flow inlet is set at a mass flow rate of 0.0001 kg/s.
3. All the other surfaces are set at room temperature.

I initialized the solver from the outer wall at 800K. The problem I have is the solution diverges after 30-35 iterations. I am having difficulty in trying to figure out where the problem lies in. I tried to define the finite rate reaction at the interface of fuel and air, but I don't know if my way of defining is hampering with the model and the solution is diverging because of that.

I also looked into the following links to get some answers but was unsuccessful

It would be helpful if I can get some answers regarding the above model including how to define a chemical reaction at an interface of fuel and air.

Varun Sagi

vbr_sagi March 19, 2010 16:19


I forgot to mention in the initial post. I am using FLUENT 12 for the modeling

black mamba March 22, 2010 03:09

Particle injection in a combustion chamber.
Hey...... I am trying to find out, when I track the particles emerging from the spray........It travels only in the upward direction......When the particle is displayed it clearly shows that all the particles travel in upward direction when it just comes out of the injection ??? I need to know why??? I need the liquid spray symmetric along the axis.......Please help.

a.m. March 23, 2010 10:56

1. Do you try to use cfx code?
2. Could you upload your case?

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