7 Replies Latest reply on Sep 13, 2016 2:19 PM by Wanfang Wu

    Heat Power Transient analysis disagrees with hand calcs

    Wanfang Wu

      Hey!

      edit: Solved:

      My error. simulation was correct. Bill McEachern is correct. I didn't set the material property under the SWX tree to 1060 aluminum so the mass evaluation tool used water to calculate mass which made my hand calc, Q=mcT, incorrect, disagreeing with the simulation.

       

       

      I have 25 Watts total entering the interior faces of my 1060 Aluminum piece, initially 20C. My transient simulation with time increment of 0.05s showed temperatures of 23.7C after 1 sec. However, I calculated a 9C temperature change using Q= mCT. Q = 25J, m = 2.9g, C = 900J/kg*K. No convection or radiation effects were modeled. What did I do wrong?

      Below are pictures of my settings. I have attached my the assembly file wherein I did my simulations.

      Many thanks!

      W

       

      Settings:

      23.7C after 1 sec with step size 0.1 (2 sec of simulation):

      transientPowerResults.PNG

      Heat Power Setting:

      transientPowerSettingTurnedOff.PNG

      Initial Temperature Setting:

      00initialTemp.PNG

       

      Confirmed 25W into system:

      25WattIn.PNG

       

      Mass properties:

      edit: this shows incorrect mass b/c tool assumed material as water for calculating mass since i didn't define material under SWX tree

      00heatingElement.PNG