Thermocapillary on film boiling heat transfer from a non isothermal horizontal surface: A theoretical study from CANDU reactors

Film boiling heat transfer from a horizontal non-isothermal surface is formulated with due consideration to thermocapillary and thermal expansion where thermocapillary convection has been largely ignored in film boiling. The study is particularity important in nuclear reactor technology where non-isothermal heater is practically the general situation due to unavoidable non-axisymmetric neutronic flux in the fuel geometries (cylindrical geometries). Utilizing a simplified geometrical model, an analytical expression was derived. The above equation applied in a sigmoidal temperature profile results in a central stratification for film boiling along the heater's length.