Old dieselSpray injector types under new lagrangian spray class
I'm trying to get the same behaviour of the commonRailInjector with the new lagrangian classes (almost repeated the thread title verbatim), and using it under something like sprayFoam. I was curious if the following section in the Properties file had anything to do with injection pressure:
Code:
constantProperties |
Though I would still like to know the answer to this question, it appears that you can specify the flowType as:
flowRateAndDischarge <-- The default one from the tutorials constantVelocity pressureDrivenVelocity <-- The one I will try and use So that would be enough for me for now, though specifying injection temperature as well would be nice too. |
Hello Marco,
It seems to me that the parameters rho0, Tvap, Tbp, and Cp0 in constantProperties should not be specified by user because all these data are already included for different liquids in /src/thermophysicalModels/properties. In fact, the initial properties can be calculated by using special formulas (e.g. see H2OI.H) whose inputs are just T0 and (gas) pressure at the injection point. So, I don't understand :confused: why the developer(s) should have written the code in the way that requires the mentioned initial injection properties, and risking the inconsistency between date inputed by user and date that are hardcoded. Any idea? |
Hello Marco. Have you been succeed with converting old properties of common rail injector to new spraycloud properties?
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what's the actual difference between this flowTypes ?? i wonder which one should i use, either flowRateAndDischarge or pressureDrivenVelocity ? Thanks in advance |
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the difference is in how he really calculates U. In flowRateAndDischarge it uses U = V_dot/(A*Cd) and in pressureDrivenVelocity it uses U = sqrt(2*(Pinj - Pamb)/rho). hope this helps... |
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that means 1. if i use pressureDrivenVelocity then i don't need to have flow rate profile (I have it from measurements). 2. whats the impact of this two different flowType on liquid penetration length ? I did the simulation with both flowTypes and rest the settings are completely same. results: The penetration with flowRateAndDischarge is very short as compared to pressureDrivenVelocity.... So i confused which one is correct. Thanks in advance! |
how to make changes of spraycloudproperties
if I change the FlowType to be pressureDrivenVelocity, which part should be modified in sprayCloudProperties?
May I have a look at your sprayCloudProperties? |
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