[sanjeetlimbu]

I am using the ignition delay model for combustion by compression stroke of cylinder... simulation to rapid compression machine. The mixture fuel is inside the cylinder compressed at 30 millisec.
I am able to run the dynamic mesh using the chem kin file for combustion . I got some results...
But I expected the combustion to make temperature rise, but i am getting early rise in temperature, while fuel also dispense early than compression end
If possible can u suggest if I entered any wrong input in initialization or model dialog box

The dynamic mesh used to show compression- for 30 millisec and combustion is expected after 30 millisec

Problem-
Everything related to combustion seem start early before compression stroke end.
Unable to get temperature/pressure rise after compression stroke at 30 ms
The mole fraction for n-heptane start from 0.0025, instead of the 0.00562 I entered in boundary condition for the model.


Please suggest how to set up the model as pressure and very low CFD post results

[sanjeetlimbu]

I am using N2/O2/nC7H16: 89.5/10.307/0.00562 as fuel mixture

I am getting early combustion - seeing P and T graph from CFD post

[sanjeetlimbu]

I checked by change in initialisation mean mixture fraction 0 and 1, so for 298K as initial temp the mean mixture fraction is needed as zero, if I enter mean mixture fraction as 1- the temperature jumps to the PDF calculated 1100K.

Since the fuel mixture become nil if I use the mean mixture fraction as zero

Pl help how to keep both temp also 298 K and fuel mixture as entered in boundary condition PDF calculation

[sanjeetlimbu]

Dear frds

I am unable to get the Pressure and temperature rise after the compression end s at 30ms.
The fuel is getting destroyed all together after the first stage but it do not result in tempeartture rise after that.
I also donot understand the rise in fuel mole fraction till the compression stroke ends!! and later though it reducess

Can u suggest possible changes needed to make it reflect changes in pressure and temp post compression combustion

[sanjeetlimbu]

Plesae someone reply to solve my issue, I am waiting ... my project is in trouble....

1. Pressure not rising during the compression stroke
2. tremperature not rising till 30ms and getting raised at instantly- abrupt
3. No combustion happening after it gets to 700K+ temp

[sanjeetlimbu]

Please help ... anyone... I am in trouble