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calculation of mass flow rate from the inner part of a vertical cylinder in natural

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Old   August 24, 2018, 08:56
Default calculation of mass flow rate from the inner part of a vertical cylinder in natural
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manoj kumar dash
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Dear all

I am doing numerical simulation of fluid flow and heat transfer from a hollow vertical cylinder in fluent. I want to find out mass flow rate through the pipe. I am performing 2-D axisymmetric case. i draw a line in the cylinder domain, but i am getting mass flow rate in negative. Can anybody kindly suggest me how to calculate mass flow rate correctly and what is wrong in my approach.
Thanking you all in advance
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Old   August 24, 2018, 09:02
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R u calculating mass flow rate at outlet?
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Old   August 24, 2018, 09:05
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No as i am performing the problem in steady state the mass flow rate i expected to be same through out the inner portion of pipe as mean velocity will be same every where. I want to know why it is giving a negative value.
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Old   August 24, 2018, 09:55
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Negative means it's going the opposite direction as the normal vector when we're talking about surfaces. With lines, the outward normal vector follows the right hand rule.


Try drawing your line in the reverse and you should get a positive mass flow.
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Old   August 24, 2018, 09:58
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Quote:
Originally Posted by LuckyTran View Post
Negative means it's going the opposite direction as the normal vector when we're talking about surfaces. With lines, the outward normal vector follows the right hand rule.


Try drawing your line in the reverse and you should get a positive mass flow.
Can you tell me in brief. I don't understand
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Old   August 24, 2018, 11:57
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Dear sire thank you very much. I have changed the y co-ordinate(reverse the position of two point), but i am getting the same negative value. Can you please tell me what you have done , had i done the same thing or am i not able to get what you told. Thanking you very much .
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