1 reply to this topic

[soorty1]

Hello All, 

 

I have been trying to solve the following problem without a concrete solution. 

 

In the JPEG attached, there are two streams combining to form a third stream, composed only of the materials and flows in the first two streams. Under steady state conditions, this would be a simple very basic mass balance. 

 

However, I am interested in the unsteady-state behavior of the third stream as the two streams combine. Specifically for a system where flow is occurring through the pipes, is followed by an adjustment in the flow rate for one of the two streams, eg  V1 or V2 is changed.  For instance, if the increase in flow rate of the one of the two streams (V1 or V2) is increased, for a period of time, there will be increased mass exiting the third stream (V3) until the the third stream reaches a the new equilibrium concentration (steady state conditions) in the third stream.

 

I was hoping if somebody has any knowledge on how to best model this system. I'm guessing it has to do with writing a differential equation that involves the length of pipe (L). I am only interested in understanding the transient behavior occurring in the length of pipe (L).

 

Assuming incompressible and inviscid flow.

 

Thank you.

 

DS

 

 

 Unsteady State Fluid Flow Solution (1).jpg   25.38KB   2 downloads

[AlertO]

Hi DS

 

Your idea sounds interested, but you need to think again that your objective is worth to do becasue the calculation will be very complicated.

 

Typically, when you want to some things about the complicated fluid flow, you may need to go to Computational fluid dynamics (CFD). You can find more information in the link below.

 

http://en.wikipedia...._fluid_dynamics

 

However, before you will go too far, i have left a notices for you to re-consider as follow:

 

If there is the real system like you gave for example, we usualy mix two streams at the design ratio and then pass through a device i.e. static mixture. After this, we can get the good solution. So, where are your mechanism applied in the real system?

 

i don't want to obstruct your interest and please apologize for my words, but it sounds not realistic for me.

 

good luck