Multiphase flow

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  • Last Post 27 November 2018
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sachin.kumar@carrier.utc.com posted this 23 November 2018

Hello I doing mutliphase flow simulation across a refrigerant distributor I am using eulerian model. I am getting very high pressure drop across the distributor around 300 psi. Actually I have a doubt on vapor particle diameter currently I am taking it default value which is 0.00001m Becaouse I don't know the actual size. So can anyone tell me how to get the approximate diameter.

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sachin.kumar@carrier.utc.com posted this 23 November 2018

If anyone have done the refrigerant distributor simulation please help me out or guide me

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rwoolhou posted this 23 November 2018

Have a look at the required flow and manifold dimensions: have you scaled it correctly? Images of the pressure contours will also be useful to aid in diagnosing the problem. 

 

sachin.kumar@carrier.utc.com posted this 23 November 2018

I have uploaded the images. If you need anything else for analysing the situation please let me know

rwoolhou posted this 23 November 2018

Please can you add images in line in future: ANSYS staff are not supposed to download files but I tend to bend that rule for images. 

Check the geometry & mesh for a conformal body. Also, what mass in & out are you getting? 

sachin.kumar@carrier.utc.com posted this 23 November 2018

Mass in is 0.0985 and out is 0.0978

rwoolhou posted this 23 November 2018

Not sure then. Please can you put some images of planes through the device showing velocity, volume fraction, temperature etc on here? 

kkanade posted this 26 November 2018

Please provide more details.

Please insert images.

 

You may want to look at following videos just for intro to multiphase. 

 

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sachin.kumar@carrier.utc.com posted this 27 November 2018

How to get the value of vapor phase particle diameter in multiphase.

kkanade posted this 27 November 2018

you can use postprocessing - contours - contours of properties of phase 2

sachin.kumar@carrier.utc.com posted this 27 November 2018

It is required before the simulation It is an input not the output.

kkanade posted this 27 November 2018

You can define diameter for the phase in phase list. 

Are you asking where to get this dia? If so, then this is input to solver. So you need to know what is diameter by experiment or by actual measurement. 

sachin.kumar@carrier.utc.com posted this 27 November 2018

Actually I don't have experimental data and not even have idea how much will be the diameter. Actually I am running two cases one at temperature -8 and -30. So my question is that the diameter will remain same or change with temperature. Currently I am taking default value

kkanade posted this 27 November 2018

As you dont have experimental data, please go ahead with constant diameter. 

Looks like in your case this would be ok. I suggest with constant dia. 

If you want further improvement then you may want to use udf for dia. 

sachin.kumar@carrier.utc.com posted this 27 November 2018

But I just checked diameter has significant impact on pressure drop. The density of the vapor phase is increasing with temperature At -8 density is 28 kg/m3 And at -30 it is 10 there is a huge difference in density So how can you say in my case constant diameter will be ok. According to me if density is decreasing which means the particle should increase.

Please tell me your consideration

kkanade posted this 27 November 2018

As you dont have experimental data, it is a good start to use constant dia with some more simplified assumption. 

As mentioned, if you want you can go ahead with udf to have dia changing with temperature. 

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