Help with PDEsolve!

[ptc-5700236]

I've been working on this file for a couple days now, but I'm not getting it to solve. I removed the reaction rate terms (R__) just to test and see if my mass balances were correct, by inputing dummy values for the R's. The balances were calculated correctly this way. SO, my problem lies in how I'm integrating my R terms into my balances, but I can't figure out what I'm doing wrong. I'm not a professional with mathcad, so it may even be a small error. Any help would great!

[ValeryOchkov]

Can you show us the description of this problrm?

[ptc-5700236]

I'm modeling a selective catalytic reactor, in which nitrogen monoxide(NO) is being removed from flue gas by reacting with ammonia(NH3). I'm supposed to build a dynamic model that accounts for diffusion and other types of transport through the reactor. What I have on that mathcad file is my approach to solving for the mole fractions of each component throughout the length of the reactor(L) varying with time(t).

[ValeryOchkov]

We (Vikror Korobov and me) have in our book

Chemical Kinetics with Mathcad and Maple

same problems

See the list of problems with Web- and Worksheet in Mathcad -

http://twt.mpei.ac.ru/TTHB/New-Chem-Kin/En-ChemKin.html

But we have only ODEs but would like to have PDEs too in the second edition of the book.

Let do it togwrger.

Now about your sheet.

You have equations after the word Given

A good trick - input = on one equation/ You must have the answer - zero (not equal), but you have

[AlanStevens · Accepted solution]

The attached might help.

Alan

[ptc-5700236]

This is good! However, I must factor in the reactor rate relationships:

Are these written correctly? Also, would I need to only specify an initial conditino for each?

[ptc-5700236]

I'm getting a "cannot load type '0.0005' " error after entering in these rates with their initial conditions. Not sure what this means, but the type '0.0005' appears to be reffering to my value for xfNO.

[AlanStevens]

Bo Bonning wrote:

This is good! However, I must factor in the reactor rate relationships:

Are these written correctly? Also, would I need to only specify an initial conditino for each?

The last three of these are included in my worksheet. The first three are rather strange as, taken with the individual definitions for RO2 RN2 etc, they imply r1 is identically zero and r2 is identically zero.

Alan

[ptc-5700236]

Okay, I've decided to continue with the help you gave me in the linked file. Now the next step for me is to determine how Temperature varies with x and t.

The equation is kinda complex, but mostly involves summation. My other equations worked, so my error has to be somewhere in this mess!

[AlanStevens]

Bo Bonning wrote:

The equation is kinda complex, but mostly involves summation. My other equations worked, so my error has to be somewhere in this mess!

Can't tell from the picture. Upload the file.

Ok! I see you have done so in another thread.

Alan