Page 455 - ExtendSim User Guide

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Mixing Flow and Items 429
Using the Interchange block to mix items with flow
Even if the source has less than 100 gallons, the buckets keep moving and grab as much water as possible. As each bucket reaches the top, its contents are released instantaneously into the sink, and the journey back down to the sink immediately starts. Running the simulation with animation on shows the buckets as they cycle from the well, up to the catch basin, and then back down again.
Bucket Elevator 2 model
The Bucket Elevator 2 model is similar to the Bucket Elevator 1 model, except there is some added complexity. In this model, the flow blocks at the bottom and top of the model represent streams of water. In the bottom stream, some of the water is removed by the buck- ets, but the rest continues on at a varying rate of flow. Likewise, after the buckets have unloaded their contents into the sink, water flows from the top stream at a vary- ing rate.
Both Interchange blocks
have a capacity of 1,000. Based on settings in the Interchange block’s Indi- cators tab, the level of
water affects the con-
straining rate of the Valve
that follows each of the blocks.
Indicators are a method of reporting
what category or range the current level
of flow falls into; the table from the
Source block’s Indicators tab is shown
to the right. An Equation block (Value
library) looks at the Interchange block’s
I (indicator) output to determine the
range the water level in the tank falls into. The block then adjusts the Valve’s maximum rate depending on that information and an equation.
The upper and lower streams in this model have different equations; the upper stream bases the Valve’s maximum rate on a constant while the lower stream bases it on a random distribution. In the lower stream for instance, if the Source tank’s level is equal to or less than the Low range, the maximum rate is a Triangular distribution that is most likely 30 units. If the level falls within or above the High range, the most likely maximum rate for the Valve is 150; other- wise, the most likely rate is 100.
Bucket Elevator 2 model
Indicators for the source
Discrete Rate
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