# Transient heat transfer simulation with variable heat source

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 February 4, 2013, 20:57 Transient heat transfer simulation with variable heat source #1 New Member   Join Date: Feb 2013 Posts: 1 Rep Power: 0 Hi, I am relatively new to CFX and am trying to simulate the transfer of heat from an electrical component to its surrounding fluid and enclosure. The component has a duty cycle and hence its power output is a dependent on time. What is the best way to simulate the fluctuating power output of the component? Thanks

 February 5, 2013, 07:38 #2 New Member   Jeremy B. Join Date: Sep 2012 Posts: 3 Rep Power: 13 Hi, It should be possible to use CEL expressions to simulate this fluctuation. Depending on the informations you have and on what you are modeling, you can use an expression to: 1) Directly control the heat generation of your system. Or 2) Control the intensity of the current in your system (you will probably also need to define an other expression if you want a temperature dependant electrical resistance) I hope I understood your problem. Does this answer your question ? Edit: "Time" or "t" are the variable "current time" in seconds in a transient simulation. "T" is the temperature if you need a temperature dependant electrical resistance.

 February 5, 2013, 17:18 #3 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,487 Rep Power: 140 You can either: * Work out the average power output and do a steady state simulation. This is a simplification but is much quicker and easier. * Model the transient on/off behaviour and run the transient until it reaches a periodic steady state. This will be a much longer simulation.

July 31, 2015, 04:33
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Quote:
 Originally Posted by rdr Hi, I am relatively new to CFX and am trying to simulate the transfer of heat from an electrical component to its surrounding fluid and enclosure. The component has a duty cycle and hence its power output is a dependent on time. What is the best way to simulate the fluctuating power output of the component? Thanks
Hi! Im interested in your simulation. Did u happen to solve this one? Wanted to compare my simulation to yours. Thanks! =)