{"id":164204,"date":"2021-11-22T20:12:39","date_gmt":"2021-11-22T20:12:39","guid":{"rendered":"\/forum\/forums\/topic\/what-is-the-limitation-caution-of-using-ewf-with-dpm-model\/"},"modified":"2021-11-26T09:36:45","modified_gmt":"2021-11-26T09:36:45","slug":"what-is-the-limitation-caution-of-using-ewf-with-dpm-model","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/what-is-the-limitation-caution-of-using-ewf-with-dpm-model\/","title":{"rendered":"What is the limitation\/caution of using EWF with DPM model?"},"content":{"rendered":"
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Hello,<\/p>\n

I am using EWF and DPM to simulate air\/water annular flow in a tube. I am using a small region in front of an annular tube to inject liquid water. Here I notice that the inlet velocity and thickness of liquid film are changing abruptly, even film velocity is going negative. I changed the droplet diameter, mesh number in the axial and radial direction, injection wall length, but nothing worked. Would you tell me what from the below may be responsible for it?<\/p>\n

1) Thick liquid film formed on the wall. I knew from some documents that the EWF model depends on film thickness. For some cases, we can use EWF, and for some cases not. Should\/ shouldn't I use EWF for shown thickness and velocity?<\/p>\n

2) High air velocity\/ Reynolds number<\/p>\n

3) Geometry\/ Mesh Configuration<\/p>\n

4) Droplet diameter<\/p>\n

I am using UDF for calculating the Entrainment rate. Even without entrainment \/droplet injection\/ UDF, film thickness and velocity are showing abnormal trends.<\/p>\n

Here are film thickness and velocity at two flow times-<\/p>\n

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