Massflow rate at inlet and outlet different | conservation of mass
 

Dear All,

I am trying to simulate ventilation in ship cargo space. For this I have modelled the HVAC duct, with contains about 12 openings as shown in the attached figure. In order to post-process using 'sample', I have created stl meshes at these openings to calculate mass flow rate using 're-sample with dataset' >calculator > integrate variable. In the calculator option I have multiplied U * rho , and then integrated this using integrate variable to get mass flow rate at all openings. Now the problem is my mass flow rate at the top inlet at fan location is about 18.5 kg/sec and sum total of mass flow rate at all outlets is about 35 kg/sec. Doesn't these two should be equal in steady state for conservation of mass...

Please help me to identify the mistake in modelling..

Regards,

Manoj