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Example Application: Gravity Drained Water Tank APMonitor Model
Description A gravity drained water tank has a level that is controlled by a valve on the inlet stream. The tank is open to the atmosphere and continuously drains through a short outlet pipe. This example shows the excellent predictive capabilities of a simple model derived from fundamental principles. The inlet valve position is controlled from 0% to 100% open. The tank level is also continously measured by a pressure sensor at the bottom of the tank. This pressure is correlated to volume of the water in the tank.
Fundamental Model A simple differential equation, derived from a material balance, describes how the level of the water will change as the inlet valve is adjusted. 
The flow into the tank is proportional to the %open of the inlet valve. The flow out of the tank is proportional to the square root of the height in the tank or volume with a constant cross-sectional area.
Control Interface 
Step Test for Model Identification 
Actual Experimental Results Test 1 |
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