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patchFlowRateInjection

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Old   July 2, 2014, 10:51
Default patchFlowRateInjection
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Clint Bedick
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Have any of you guys used the patchFlowRateInjection injection model?

There is one required input that I'm unsure of. You must specify a "concentration", which the source file describes as "concentration profile of particle volume to carrier volume", and is non-dimensional. But I also must specify a true particle concentration, in #particles/m3, and also a total mass to inject. In addition I have a constant particle density and set a size distribution.

How can all of these values be specified at the same time? Ideally, I would like to just say, I want to inject n particles from t0 to t1.

I'd appreciate any additional info on this injection model. I'm in the process of experimenting with these parameters.

Thanks,

-Clint
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Old   July 5, 2014, 16:54
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Clint Bedick
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I just wanted to respond back to this in case others are searching for info related to this boundary condition.

Basically, you only need to specify (2) parameters: concentration and parcelConcentration. If you specify parcelBasis as "number", the totalMass value is not used at all. For my simulation, I want each parcel to only be made up of a single particle. So I set nParticles to 1 and just played around with values for concentration and parcelConcentration until I introduced the number of parcels I wanted. If you want to be exact about the parcel injection rate, you will need to specify a fixed particle size and number of particles per parcel so you can compute the ratio of the volume flow rate of particles to volume flow rate of gas, and then set the concentration as your actual number of parcels per volume of gas.

Either way, this boundary condition appears to work well to inject particles at the gas velocity, especially when you have a variable inlet velocity (groovyBC, etc) that makes it tough to directly specify the initial particle velocity for a patch injection.
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