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How to deal with parameters or variables having units with fractional or non-integer powers
Posted Jan 27, 2015, 9:27 a.m. EST Chemical Reaction Engineering 2 Replies
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Hi,
In simulation of reacting flow like reactors, there are parameters or variables like k, and -rA having units with fractional or non-integer powers, like
mol.bar^0.5 or
mol^0.3.s^-1.
Comsol throws warning and in defining other parameters based on them it raises errors.
One way is to make the whole problem dimensionless, but this is not an easy task in many cases. Moreover the predefined Comsol physics are not dimensionless.
I would appreciate if there is a way to resolve this issue.
--
Best regards,
Saeid
In simulation of reacting flow like reactors, there are parameters or variables like k, and -rA having units with fractional or non-integer powers, like
mol.bar^0.5 or
mol^0.3.s^-1.
Comsol throws warning and in defining other parameters based on them it raises errors.
One way is to make the whole problem dimensionless, but this is not an easy task in many cases. Moreover the predefined Comsol physics are not dimensionless.
I would appreciate if there is a way to resolve this issue.
--
Best regards,
Saeid
2 Replies Last Post Jan 28, 2015, 8:03 a.m. EST
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Posted:
10 years ago
Hi,
I have used following method:
r = 5.012e11[m^3/(kmol*s)]*exp(-24054[K]/T)*c_O2*((c_CH4[m^3/mol])^0.5)[mol/m^3]
In this only concentration, c_CH4, is converted to dimensioless and after power 0.5 it is turned back to concentration.
Best regards
Tero Hietanen
I have used following method:
r = 5.012e11[m^3/(kmol*s)]*exp(-24054[K]/T)*c_O2*((c_CH4[m^3/mol])^0.5)[mol/m^3]
In this only concentration, c_CH4, is converted to dimensioless and after power 0.5 it is turned back to concentration.
Best regards
Tero Hietanen
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Posted:
10 years ago
Hi Tero,
Thank you for your response. It is a quite method. I will definitely try that.
Thanks again,
Best regards,
Saeid
Thank you for your response. It is a quite method. I will definitely try that.
Thanks again,
Best regards,
Saeid