Temperatur result is higher than the temperatur load ?

- July 6, 2023 at 11:40 am
  
  Tim Fricke
  Subscriber
  
  Hey Everyone,
  I have a problem with my transient thermal calculation. I have two components that are connected to each other with a contact.
  
  Now I apply a heat load for one second and ramped to 220°C, to the smaller part in the middle. After that I deactivate the heatload and want to observe the cooling behavior of 16 sec.
  So far so good. But If I now look at the temperature results, the maximum temperature after the heatload is deactivated continues to rise up to 343 degrees. How is this even possible?
  Does anyone know how this could happen?
  Best regard
  Tim
- July 7, 2023 at 2:21 pm
  
  dlooman
  Ansys Employee
  
  Also, there is a negative temperature which is non-physical. This issue appears to be the result of using too small a time-step relative to the 2nd order element size. The smallest time-step that can be used is given in Section 3.4.3.2 of the APDL Thermal Analysis Guide. Workarounds are using a finer mesh, increasing the time step or using first order (Linear) elements.