The discussion centers on modeling a heat exchanger in Simulink using the UA curve, which represents an instantaneous value rather than a dynamic model. Participants agree that while the UA curve can provide a functional relationship, it does not inherently capture dynamic behavior due to its reliance on steady-state data. The conversation highlights the common treatment of heat exchangers as instantaneously reacting devices, particularly in educational contexts, and emphasizes the need for further context to evaluate the model's effectiveness in simulating a rotary air compressor system.
PREREQUISITESEngineers, system modelers, and researchers involved in thermal system design, particularly those focusing on heat exchangers and rotary air compressors.
Do you think, is it because the test data gives the details of only at steady state ?BvU said:Nope.
I agree. I think we need to hear more details. But it might be a decent approximation if UA where used in a dynamic case based on the instantaneous conditions. It depends.BvU said:I do. UA is an instantaneous value, a curve makes it a function of something.
On the other hand, dynamics of heat exchangers aren't often a focus (except perhaps in textbooks): I've always seen them treated as instantaneously reacting devices because the heat content of vessels, columns and reactors and such was so much greater. Do you have a particular application in mind ?
@Chestermiller : any experience ? -- and shouldn't we let the OP add some more context ?
My end objective is to make complete simulink model for rotory air compressor. So this heat exchanger will become one of the subsystem in my model. Can you tell me, if I am using a heat exchanger modeled with this approach can mimic the actual system functionality?BvU said:I do. UA is an instantaneous value, a curve makes it a function of something.
On the other hand, dynamics of heat exchangers aren't often a focus (except perhaps in textbooks): I've always seen them treated as instantaneously reacting devices because the heat content of vessels, columns and reactors and such was so much greater. Do you have a particular application in mind ?
@Chestermiller : any experience ? -- and shouldn't we let the OP add some more context ?
Like in this picture by Brian S. Elliott - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=66663474 ?Nikhil N said:complete simulink model for rotory air compressor