Store state or signal, if speed or flow is zero

Hello,

I am trying to build up tubes for liquids, which handle a bus of volume flow, temnperature, densitiy and heat capacity. Currently I'm using the delay-block, to calculate transit time dependent on vflow and tube geometry. Only temperature is affected by the delay so far.

My problem: What happens, when the flow becomes zero? Is there any possibility to "store" the state of a signal, because the liquid with different temperatures won't move? In my case that would mean, I store the tube input and output while vflow == 0. Any device connected to output should only read the stored output then.

Ah.... Another problem: Example: Before vflow reaches zero, the delay will be 10 s. Then vflow is 0. So "10 s" should be stored anywhere and available after vflow > 0 again. What possibilities do I have?

[Seth Popinchalk]

Are you modeling the tube as a no-delay system? Often the transport delay block is used to describe systems like this.

[Andreas]

I'm currently using the delay-block as desribed in sldemo_VariableTransportDelay_pipe. Ther you'll face the same problems. How to store the tube's state, when flow gets zero and thus delay time gets infinite?