CI simulation
hi
I'm a novice user in AVL FIRE. i want to simulate the closed Cycle of CI Combustion. of course my compression ratio is 11 & for this reason i used high temprature in beginning of cycle (550 K in BDC). injection is done in 697 deg ,but i have a very weak ignition. for example my burnt fuel mass fraction is 0.000005 in 720 deg & maximum rate of heat release is 2 j/deg!!! as a another result i have a motoring pressure for my pressure diagram!! I checked any data, but i didnt have any success in my problem.. tnx for any help & proposal. |
Hi,
Even though your information is not enough, please check.. - initial cylinder pressure - injected/evaporated/remaining fuel mass - cylinder pressure/temperature trace during simulation If Breakup/Evaporation are OK, you should check the combustion parameters. After check, please show more information. |
i checked all of this parameter that you said before, & they are not logical for self ignition.
but i got a great point that fractions of air components are not logical at all. in fla file & species mass fraction: for example O2 mass fraction is about 1e-10 & N2 is about 0.7!! i think this is my problem, that i dont have any choises in fluid propertis for air.. combustion model is eddy beak up my initial pressure is 256000 Pa. tnx for any suggestion. |
looks strange.
I guess you defined EGR mass fraction in initial condition. Please describe your inputs in "Standard species transport" of INITIAL CONDITIONS. Did you also check spray evaporation? |
yeah,your guess is true. i had a mistake that defined the EGR mass fraction in initial condition. after solving this problem i run my case & there are some results that obtained:
max Rate of Heat release: 29 j/deg max burnt fuel mass fraction:0.008 max mass fuel evaporated: about 8e-5 kg fuel mass: 0.00037 kg i dont have a good fuel evaporation & i can't find this reason.. fuel is diesel & maximum temprature is 1100 K. tnx... |
hi guys!
im recently working by fame engin plus.any body knows in fame engin plus at input surface section what is the range of cranck angle(valid from... to... cranck angle)? |
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