question

pc neo avatar image
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pc neo asked pc neo commented

FloWorks library has geared OGVs?

1) I will like to model a geared OGV (task executor flowitems), that is, it is a vessel that has cranes on it to load fluid from smaller barges/vessel. From the tutorial i learn that i need to add berth and loading arms so that the OGV will parked and be loaded. However, this berth is a fixed object. It is not exactly the same as the above scenario. Is there an object in FloWorks that can meet my need?


2) Another thought I have is to create LoadingArms and Berth and connect to every OGV (task executor flowitems) that is created on the fly. However, I believe I will need to "reset" the model with addition of new connection. This approach will fail. Am I right?

FlexSim 18.1.1
FloWorksfloworks module features
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1 Answer

Patrick Zweekhorst avatar image
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Patrick Zweekhorst answered pc neo commented

Hi @pc neo,

Let me answer your second question first. No, you can create and destroy connections on the fly. There is no need to reset your model. If you have some kind of flowObject you can simply connect it to another flowObject by using the "flowObject.connect( otherFlowObject ) " command. This command connects the flowObjects and lets flow flow through the model, when possible. This connection can be destroyed with "flowObject.output.ports[1].disconnect" when you no longer need the connection.

With this connection and disconnection functions you can connect two flowVessels and let barges empty an OGV. I have done this in the example model. Note that I have added an OGV object to the flowItemBin. This is a flowVessel with a loading arm in it. There is actually no real need to use the loading arm, you can also directly connect the two tanks to each other if you want.

If you have any questions about this model please let me know. I don't mind explaining it a bit further. There might be other solutions possible as well, but I think this does what you want.

Patrick Zweekhorst

floworksdemo.fsm


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floworksdemo.fsm (40.3 KiB)
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pc neo avatar image pc neo commented ·

thank you. This looks promising.

I'll work base on your suggestion. I will come back to you if I have more questions. :D

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pc neo avatar image pc neo commented ·

Queries in regards to this sample model, in the case when I put in 2 LoadingArms on the OGV, it 'looks' like it is unloading one at a time. (refer to the attached model)

a) How can we configure it to unload simulatenously?

b) Is there a way to get the loadingarms statistics?13529-floworksdemo-gearedogv-try.fsm

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13529-floworksdemo-gearedogv-try.fsm (45.6 KiB)
Mischa Spelt avatar image Mischa Spelt pc neo commented ·

Hi. It looks like you have a bug in your model. You are not using the loading arms at all at the moment - you are still connecting the tanks directly. It does seem like you are trying to disconnect the loading arms, which means that leaving vessels will also stay connected. You can more easily see the problem when you enable "Show Connections":

In your "Connect OGV loadingArm to Barge" activity you have

token.ogv.Compartment.as(FlowObject).connect( token.barge.Compartment )

which should be

token.ogv.LoadingArm1.as(FlowObject).connect( token.barge.Compartment )

// or, for the other activities,

token.ogv.LoadingArm2.as(FlowObject).connect( token.barge.Compartment )
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13590-13529-incorrect-connections.png (2.2 MiB)
pc neo avatar image pc neo commented ·

@Mischa Spelt thank you for the tip on the changes to make to use the loadingArms. That works well.

@Mischa Spelt and @Patrick Zweekhorst I still have a query that is with the above changes made, I still have the issue of not able to load 2 barges simultaneously, that is, at the same time. In my model (as attached) I have made 2 barges present at the same time, and since there are 2 loading arms, I am expecting both loading arms to be used at the same time, one for each barge.

Help is appreciated.13529-floworksdemo-gearedogv-try1.fsm


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13529-floworksdemo-gearedogv-try1.fsm (45.6 KiB)
13529-floworksdemo-gearedogv-try1.png (238.1 KiB)
Mischa Spelt avatar image Mischa Spelt pc neo commented ·

Hi @pc neo,

Both loading arms are used at the same time, but your OGV's tank does not have sufficient outflow capacity. The maximum outflow of the source tank is 5, and both loading arms have a maximum flow rate of 5 as well.

By default FloWorks distributes flow using the Preferred Flow Order rule, which means that earlier connections maximize their flow. In this case, the first loading arm will take up the whole outflow capacity of the OGV compartment, and the second loading arm will be starved waiting for the first barge to leave.

The easiest way to fix this is to set the loading arm rates to half of the OGV outflow rate in the FlowItem Bin (e.g. set the loading arms to 2.5 or set the OGV tank outflow to 10).

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13765-13529-floworksdemo-gearedogv-try1.png (84.4 KiB)
pc neo avatar image pc neo Mischa Spelt commented ·

thank you for the detail explanation. Now I realize my mistake. :)

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