Dear combustion modellers

For the time being, I am solving combusting flow inside the combustor of incineration plant. My approach is fairly simple. At first, I assumed that all combustibles, including fixed carbon C(S), as volatile matter. And next, I am solving the problem with gas phase combustion with assumed distribution on the grate which is modelled as couple of inlet. Volatile matter is modelled several family of fuel whose composition are CxHyOz. I think that my approach is nearly same as those of ABB and ANSALDO.

I think that I can give good insight to the incinerator designer about gas residence time and flow characteristics in accordance with secondary air nozzle design. However, some experimental researchers always ask me 'why don't you include the behavior of (very large and many) moving solid waste. One researcher said that someone in Europe is trying to solve the combusting flow inside the solid waste combustor of incinerator including the dynamic behavior of (very large size, thousands of, moving and combusting) solid waste.

Do you think that is it possible mathematically ? If possible by mathematics, when, do you guess, can it be solved considering the development of both computer and software ?

Jinwook LEE

(1). It is a matter of speed and memory. ( of the computer, or the computer systems ) (2). If you use a computer to track a large particle, then one thousand computers should be able to handle one thousand large particles. (3). It can be done, but it will not increase the combustion efficiency to 100%. (once you know it can be done, you don't have to do it. if you are not sure whether it can be done or not, you can try it.)

THE CENTER FOR SIMULATION OF ACCIDENATAL FIRES AND EXPLOSIONS AT THE UNIVERSITY OF UTAH/SALT LAKE CITY

will work toward providing a set of state-of-the-art, science-based tools for numerical simulation of accidental fires and explosions, especially within the context of handling and storing highly flammable materials. The simulation study will contribute improved understanding of fire safety and accident scenarios, and for civilian benefits- reduced risk, increased safety and potential remedies in situations such as industrial chemical fires, the handling and transportation of highly flammable materials, terrorists attacks or car crashes.

ASCI Program Centers of Excellence supported by Department of Energy.

Dear John C. Chien

CC : incinerator designers and modellers

Thank you for your comment for my question. You think that my problem CAN be solved by current mathematics if we have VERY VERY POWERFUL computing system.

Would you give me brief comment how the dynamic behavior of very large combusting solid(not particle but lump of solid) can be coupled with Navier-Stokes equation ? Do you mean sliding mesh technique ? Your comment would be very helpful for me to get insight for my future plan.

Actually speaking, my opinion is : it is impossible to solve the such a problem within ten or twenty years even though someone has his own supercomputer. And I think that it is meaningless even though it can be solved, considering the overall accuracy and the engineering sense to apply the result to the basic design of incinerator. I would like to hear your strict opinion.

Sincerely, Jin Wook LEE

(1). You can consider your lump of solid ( not a particle) as complicate as a space shuttle. They can compute the flow over a complete space shuttle, a fighter or a commercial aircraft. (2). I think they can also simulate fighter and missile launching together and track the missile. (3). Dropping a missile or a bomb has been done in 80's, so by now they should be able to compute more than one bomb. For this type of problem, overlapping mesh is used. Each body ( a missile, a bomb, or a lump of solid) has its own enclosed mesh, and they can move easily through the main flow field. (4). Just the geometric animation alone, it has been done in the animation movies for some times. In the animation, the models were animated but the flow field was not computed. (5). The biggest problem you have is " you have to know the geometry of these lump of solid first". That's the only problem.

Jin,

I succesfully simulated incinerator problems for my Master's Thesis. I am very empathetic to your cause. Please email me for more information, I would be happy to share it with you. Specifically, I have worked on the chemistry, residence time, radiative ht, reactive flow, and some lagrangian multi-phase aspects of an incinerator. I think it would help you out a lot.

Tony