{"id":373516,"date":"2024-07-25T03:05:48","date_gmt":"2024-07-25T03:05:48","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/volume-fraction-too-low-how-to-improve\/"},"modified":"2024-07-25T03:05:48","modified_gmt":"2024-07-25T03:05:48","slug":"volume-fraction-too-low-how-to-improve","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/volume-fraction-too-low-how-to-improve\/","title":{"rendered":"Volume Fraction too Low. How to Improve?"},"content":{"rendered":"

Hi, I am trying to simulate Multiphase condensation on a single tube. Below is my geometry image.<\/p>\n

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I use Multiphase > VOF > Implicit > Sharp > Evaporation—condensation at 300K with 500 condensation frequency as a condensation model with transient flow. The gravity is -9.81.<\/p>\n

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Tube wall temperature is 273.15K from Cell Zone > fixed values. <\/p>\n

Inlet = mass flow rate of Vapor Ammonia is 0.00414282Kg\/s with a temperature of 300K and a pressure of 1061700Pa.<\/p>\n

Outlet = backflow temp = 297K with Backflow VF = 1. Pressure = 968150Pa.<\/p>\n

The pressure, thermal conductivity, etc., are taken from REFPROP at saturation temperature. <\/p>\n

Hybrid initialization with an initial patch of vapor in the whole domain. <\/p>\n

I have done many variations but the volume fraction I am getting is very very low . how can I improve the volume fraction?<\/p>\n

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I have share residuals, mass flow rate (in\/out), vapor in domain(100%), Liquid out (0%), heat fluxes. what do I need to share more?<\/p>\n","protected":false},"template":"","class_list":["post-373516","topic","type-topic","status-closed","hentry","topic-tag-multiphase_models-1","topic-tag-multiphaseudfevaporationdpmspeciestransportdefinesourcesourcetermeulerianlagrangian-1","topic-tag-condensation-evaporation-1","topic-tag-ImplicitVOF-1","topic-tag-multifluid-vof-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t