Consider fully developed laminar flow with constant properties in a circular tube. Let there be heat transfered  to or from  the fluid at a constant rate per unit of tube length.Additionally, let there be heat generation within the fluid, (perharps by nuclear reaction.) at a rate S, W/m^3,that is everywhere the same. Determine an expression for the nusselt number as a function of the pertinent parameters , (what are they?).Evaluate the convection conductance in the usual manner,based on the heat flux through the surface,surface temperature and fluid mixed mean temperature.