Hello Everyone,
I am currently working on fluid dynamics and I have one question:
I am studying about the fluid flow from a cylindrical pipe. and I have got how to find the velocity profile and flow rate.
My question is what should be our approach when the pipe from which the fluid is passing, has variable temperature? Means, the temperature of the pipe is getting increased due to some hardware components, which are attached outside the pipe at different positions along the length of the pipe?
which parameters of fluid can be affected and how to model them?
Thank you
Raza
A general and simple one-dimensional theory for compressible non-adiabatic flows is provided by the Rayleigh flow. You can add also friction by considering Fanno theory.
If you need of specific multidimensional details in the flow, you can simulate the pipe flow using non-adiabatic walls and prescribing along them the heat flux. A more complex simulation would involve the details of the devices in a conjugate heat transfer flow problem.
Obviously at points of variable wall temperature, the fluid viscosity will fluctuate influencing the change in entropy generation rate.Therefore, I think that a temperature dependent viscosity model be used to accommodate for variable wall temperatures.If your flow is turbulent, the k-e model suits.
You can add the heat either as a boundary condition or source/sink in the governing equation of heat transport.
A general and simple one-dimensional theory for compressible non-adiabatic flows is provided by the Rayleigh flow. You can add also friction by considering Fanno theory.
If you need of specific multidimensional details in the flow, you can simulate the pipe flow using non-adiabatic walls and prescribing along them the heat flux. A more complex simulation would involve the details of the devices in a conjugate heat transfer flow problem.
Dear Raza,
First find the condition on Mach No. If you find Mach No. less then 0.3 then you can assume density change due to flow can be neglected and you solve the flow field using a pressure based solver with a SIMPLE scheme. If not then refer back to flippo's answer
If you know the temperature function on the wall which varies with space or time then it is easy to write a UDF which can be used as a wall temperature boundary condition.
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