Say for a 10nmx1nm graphene sheet,is it possible that the thermal conductivity component along the y axis is greater than the x axis?
Since different thermal conductivities have been reported for zigzag and armchair systems, then yes, it is possible.
However, if you are relying on unsourced answers (like mine) given to you by strangers in forums, I would say that you are not doing it right. 
You need to compare the values you obtain with the literature. Similar measurements have been made countless times in the case of graphene.
Simon
Ok Sir,thanks for your words.