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CFD from stationary to time dipendent
Posted 8 nov 2012, 13:31 GMT-5 Computational Fluid Dynamics (CFD), Heat Transfer 1 Reply
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I built a model of pipe in axialsymmetric configuration, with internal laminar flow of water with pre-determinate velocity.
The water flow, during its pass, are heating by resistor, simulated as heat source with the total power put into the system.
I obtained a stationary solution, but now i want to study the evolution of system's temperature for three second when the velocity flow change suddenly to zero.
The water flow, during its pass, are heating by resistor, simulated as heat source with the total power put into the system.
I obtained a stationary solution, but now i want to study the evolution of system's temperature for three second when the velocity flow change suddenly to zero.
1 Reply Last Post 9 nov 2012, 01:44 GMT-5
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Posted:
1 decade ago
Hi
sounds like a reasonable demand, I would run your stationary case, thena add a second time stepping solver case and link it to the stationary and use that as "initial conditions, but turn "off" the flow velocity with a parameter or a bolean condition.
Note: in the stationary case the variable "t" for time is not defined, if you mix in som eformulas with "t" they would be flagged with an error for your stationary case. The easiest is to add a Parameter t = 0[s] and you could vrite for the inlet velocity Vin*(t[1/s]=0), this would hold for the statioanry case with t=0 from the Parameter, and would make the link to the time series as then t is defined by the solver variables, make t=range(0,0.1,1)*3 or something like that, but be sure the time steps are small enough to see your effect. The heat diffusion in water is low only some 0.15[mm^2/s] so you need 100 sec to travel 1.5 mm with your heat "flow"
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Good luck
Ivar
sounds like a reasonable demand, I would run your stationary case, thena add a second time stepping solver case and link it to the stationary and use that as "initial conditions, but turn "off" the flow velocity with a parameter or a bolean condition.
Note: in the stationary case the variable "t" for time is not defined, if you mix in som eformulas with "t" they would be flagged with an error for your stationary case. The easiest is to add a Parameter t = 0[s] and you could vrite for the inlet velocity Vin*(t[1/s]=0), this would hold for the statioanry case with t=0 from the Parameter, and would make the link to the time series as then t is defined by the solver variables, make t=range(0,0.1,1)*3 or something like that, but be sure the time steps are small enough to see your effect. The heat diffusion in water is low only some 0.15[mm^2/s] so you need 100 sec to travel 1.5 mm with your heat "flow"
--
Good luck
Ivar