STEADY STATE STEADY FLOW (SSSF) PROCESS 1

[142846]

In thermodynamic there is an important issue "STEADY STATE STEADY FLOW (SSSF) PROCESS".

MY QUESTION IS:
Is there any steady flow process that is not steady state? or is there any steady state process that is not steady flow?
what is the difference between steady state and steady flow process?
what is the examples of for example for steady state none steady flow process? or steady flow non steady state process?

thanks for any respond.

 

[Latexman]

You can have steady flow in a plug flow reactor, but that may not be a steady state process due to the reactions that may be going on.

Good Luck,
Latexman

 

[Rputvin]

A lot of industrial cooling loops are setup as combinations of steady-state, steady-flow, and shift between at various stages of their process. A strict definition might say it is never steady in either regard, but for the purposes of analysis a stretch of several hours with unchanging conditions is likely steady enough. Or the same loop can be designed a multitude of ways depending on the particular arrangement, operating method, existing equipment, plant needs, etc.

A water cooled air compressor usually receives steady flow. It cycles on and off as needed to fill a reservoir or for use by the plant. If it runs for 15 minutes on, 15 minutes off, all day long, this loop may be best analyzed as steady flow, non-steady state. Hook the same compressor to a large accumulator tank and it now runs for several hours at a time so it may be better analyzed as steady flow, steady state, and the non-load times ignored. It might be equipped with a variable speed booster pump as part of a central cooling system and the loop is only at full flow when the compressor is running in short intervals, which becomes non-steady state, non-steady flow (or very short steady intervals).

 

[JStephen]

Just pulled out the ol' Thermodynamics book. They associate steady-flow with fluid movements and steady-state with thermal changes. More specifically, there are steady-state problems that do not involve flow at all (radiation, conduction problems) and also fluid dynamics problems where thermal changes are insignificant.