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sbu March 17, 2010 05:25

Diesel substitute

I want to simulate the breakup of diesel droplets and therefore I'm searching for a diesel substitute. Bescause I only focus on breakup, the relevant properties for me are density, viscosity and surface tension.

I already checked the source files of several liquids, but I don't understand how the properties are definded.

Which liquid should I use or can sombody explain me how to find out myself?

Pauli March 17, 2010 11:55

In SAE paper 1999-01-0528, the authors show n-heptadecane provides the best liquid length match with DF2 data.

sbu March 17, 2010 14:32

Hi Pauli, thanks a lot for your answer.

Heptadecance seems to fit quite well here. But the problem is that my droplet temperature should be 293 K, which is a few degrees below the meltingpoint of C17H36.

Further more, heptadecane is not implemented in OF, so that I will probably use hexadecane or tetradecane. I found out that their properties are almost equal to the ones of my diesel (rho=831Kg/m^3, sigma=0.026kg/s^2, mu=0.0023Pas).

However, I still don't know how to compare these values to the ones in OF, just to be sure. I'm looking forward to some help.

Thanks, sbu

niklas March 18, 2010 06:01

Here's a small utility I use from time to time.
It might be helpful

unpack it
go to the liquidProp directory and run 'wmake'
go to the example directory and edit your fuel in constant/thermophysicalProperties

run 'liquidProp -T 350' and it will calculate the density at 350 K.

Add additional info statements in liquidProp.C if you want, it should be obvious how to do it.

sbu March 18, 2010 19:19

Thank you very much, Mr. Nordin. That program works well.

But I've got a new problem now. I've chosen c14h30 as liquid in the thermophysicalProperties file, but I found out that it is not listed in the thermo.dat list.

I haven't found out much about the thermo.dat file and chemkin readers yet, but I hope that there is a way (which is not too difficult) to add c14h30 to the list.

I would be happy about some support.

Thanks in advance, sbu.

niklas March 19, 2010 02:49

google 'burcat' or go here directly

just copy/paste the c4h30 stuff into the therm.dat.

as for the chemistry part, you have to figure that out yourself.
If you want to start with just a global reaction being converted to co2 and h2o,
that should be straightforward to just modify the coefficients for the existing c7h16 example.

sbu March 22, 2010 19:06

Thank you very much again, Mr. Nordin.

That information helped me a lot, although I couldn't add the c14h30 data to the therm.dat file correctly. I hope to solve this problem soon.

Sincerely yours, sbu.

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