chemical equilibrium of a gasifier using fsolve
in [Matlab]
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From: Steve Amphlett on 17 Jun 2010 10:47 "Gavin " <wigging(a)gmail.com> wrote in message <hvd7hu$202$1(a)fred.mathworks.com>... > "Steve Amphlett" <Firstname.Lastname(a)Where-I-Work.com> wrote in message <hvcrjd$oug$1(a)fred.mathworks.com>... > > > > This system of equations is very difficult to solve using traditional methods. When your concentrations approach zero, some of the equations are either no longer valid or just go crazy (division by near zero). I'd be suprised if simply packaging them up and passing them to a canned solver is going to work without a lot of fiddling. I would search the literature for custom solvers for this well-known problem and implement them directly in Matlab. > > Steve, > Would you happen to know of any such solvers that I could apply to this problem? Thanks. I think most engine simulation (1D, 3D) programs have some form of solver for these equations, but none would be prepared to hand it out. When I worked on ours, I was heavily guided by Heywood's "Internal Combustion Engine Fundamentals", probably not quite in your field, but the same problems to solve nevertheless. He says: "Standardized computer methodsfor the calculationof complex chemical equilibrium have been developed. A generally available and well documented example is the NASA program of this type." He then goes on to spend a few pages describing how it works and shows some plots of outputs. The NASA ref is Svelhla, R. A. and McBride, B, J. http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730007227_1973007227.pdf It's old (1973) and it's in FORTRAN IV. Others exist, but they generally are for sale, not free. Googling "Thermochemical Equilibrium" provides some interesting links that have all the right words. E.g. (possible wrapping problems here): http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2P-4KCHCY6-1&_user=10&_coverDate=01%2F31%2F2007&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1372914681&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=7d7e09d97b2f5234f0a07d3ed958145b |