How do I set scalar boundary condition?

November 22, 2006, 22:47

Hi, everyone..

I have something make me confusing.

I am trying to analyze SI engine(of course, with octane)

I am using Weller-1 model with conditional enthalpy model.

Then, I got 6 scalars (C8H18, N2, O2, CO2, H2O, RVB).

I don't know the meaning of RVB but it's not a problem.

I have set initial mass fraction of initially charged AIR of scalars like below.

(C8H18:0.0637, N2: 0.7183, O2: 0.218, RVB: 1)

I've referenced theoretical fuel equivalence ratio of octane and RVB fraction as weller model tutorial.

Now, I have a question. When I set boundary scalar mass fraction of the inlet, what value I have to use for RVB?

Same as initial field? Anyway, I temporarily setted the inlet RVB mass fraction as 1 and found that combustion was successfully have occured. But I want to get a more precise information about setting RVB mass fraction.

Thank you~

Robert_B · December 5, 2012, 14:24

RVB is regress variable b. It's a non-dimensional scalar variable, which has value 1 in the unburned state and 0 in the fully burned state. It is defined in the StarCD methodology volume.

Presumably your inlet stream is a mixture of fuel, oxygen and nitrogen? Assuming that the stream is completely unburned where it enters the domain, you should set the stream's value of RVB to be 1.

Robert

November 22, 2006, 22:47	How do I set scalar boundary condition?	#1
D.K lLee Guest Posts: n/a	Hi, everyone.. I have something make me confusing. I am trying to analyze SI engine(of course, with octane) I am using Weller-1 model with conditional enthalpy model. Then, I got 6 scalars (C8H18, N2, O2, CO2, H2O, RVB). I don't know the meaning of RVB but it's not a problem. I have set initial mass fraction of initially charged AIR of scalars like below. (C8H18:0.0637, N2: 0.7183, O2: 0.218, RVB: 1) I've referenced theoretical fuel equivalence ratio of octane and RVB fraction as weller model tutorial. Now, I have a question. When I set boundary scalar mass fraction of the inlet, what value I have to use for RVB? Same as initial field? Anyway, I temporarily setted the inlet RVB mass fraction as 1 and found that combustion was successfully have occured. But I want to get a more precise information about setting RVB mass fraction. Thank you~

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December 5, 2012, 14:24		#2
Robert_B New Member Robert Join Date: Mar 2011 Location: Cambridge UK Posts: 11 Rep Power: 15	RVB is regress variable b. It's a non-dimensional scalar variable, which has value 1 in the unburned state and 0 in the fully burned state. It is defined in the StarCD methodology volume. Presumably your inlet stream is a mixture of fuel, oxygen and nitrogen? Assuming that the stream is completely unburned where it enters the domain, you should set the stream's value of RVB to be 1. Robert