Field variables, https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v232/en/flu_ug/flu_ug_FlowVariableDefs.html but also have a look at where (and what) you're adding on the thermal bc. Also, where it's going.
A heat flux boundary will adjust facet temperature to enforce the flux, temperature will adjust the flux. So, with flux it's possible to get very high (or low) temperatures depending on the flow field: with temperature the flux can be non-physical.
You are navigating away from the AIS Discovery experience