How can I do the dimensionless wall heat flux ?
 

hellow I want to do the dimensionless wall heat flux. The form is the Q*=( -(delta T*)/(delta x*) ). The T*=(T-T_c)/(T_h-T_c), where the T_c is the cold wall temperature and the T_h is the hot wall temperature. And the x*=x/L.

Can somebody help me? Thank you.