Learning Forum

[315914335]

The temperature prediction of thickened flame model in FLUENT is too high. What is the reason? Using the one-step kerosene mechanism, the TFM settings are as follows. At the same time, what is the role of the temperature threshold? In this case, the temperature predicted is more than 3200K.

[315914335]

upup

[315914335]

upup

[Ren]

A likely cause of the excessively high temperature is the lack of inadequate convergence of the energy equation. Please try the "Stiff Chemistry Solver" that can be selected from the dropdown list under "Chemistry Solver".

The Temperature Threshold is to save computational cost by assuming the reaction rate is zero for temperature values below the threshold.

 

[jcooper]

Hi Jiacheng:

A one-step mechanism is very crude chemistry to describe a process that in reality has hundreds of chemical reactions.  For an example, you can visit the UC San Diego page, where the base mechanism can be used + the heptane chemistry to approximate kerosine:

https://web.eng.ucsd.edu/mae/groups/combustion/mechanism.html

Another way to approach fuel mixtures is to develop surrogate fuel mixtures for which the chemistry is known. This type of work can be conducted with Chemkin and is described in the paper at the link below:

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8444312/