Defining suction pressure for outlet without inlet

Geetesh.waghela · April 29, 2020, 11:53

I am simulating a tank with urea filled in it. There is no inlet and i have a outlet vertically upward with suction pressure of 9 bars.
I have to simulate the suction of liquid urea and the pressure differemce created when urea level decreases.
I am getting vof divergence while simulating this( urea is not moving upwards) . Any tips would be very helpful.

vinerm · April 29, 2020, 12:53

Suction Pressure cannot be more than 1.01325 bar. Secondly, if there is no inlet, what do you expect to be filled in the void that would be created by the leaving urea? Either urea is being modeled as a compressible liquid or there is inlet for gas or other liquid.

duri · April 29, 2020, 16:06

Think physically what would happen in the tank. Some amount of fluid would displace and the pressure drops. Whether this leads to vacuum (in this case single phase is enough) or fluid vapor fill the chamber (should be solved like cavitation) it should be modeled accordingly. Nevertheless the solution will diverge near the physical limit.

April 29, 2020, 11:53	Defining suction pressure for outlet without inlet	#1
Geetesh.waghela New Member Geetesh Waghela Join Date: Nov 2017 Posts: 2 Rep Power: 0	I am simulating a tank with urea filled in it. There is no inlet and i have a outlet vertically upward with suction pressure of 9 bars. I have to simulate the suction of liquid urea and the pressure differemce created when urea level decreases. I am getting vof divergence while simulating this( urea is not moving upwards) . Any tips would be very helpful.

April 29, 2020, 12:53	Suction Pressure	#2
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 36	Suction Pressure cannot be more than 1.01325 bar. Secondly, if there is no inlet, what do you expect to be filled in the void that would be created by the leaving urea? Either urea is being modeled as a compressible liquid or there is inlet for gas or other liquid. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

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April 29, 2020, 16:06		#3
duri Senior Member duri Join Date: May 2010 Posts: 245 Rep Power: 17	Think physically what would happen in the tank. Some amount of fluid would displace and the pressure drops. Whether this leads to vacuum (in this case single phase is enough) or fluid vapor fill the chamber (should be solved like cavitation) it should be modeled accordingly. Nevertheless the solution will diverge near the physical limit.