Heating and
boiling of water are amongst the most basic processes. A model of nucleate pool
boiling with surfactant enhancers is developed. The model combines a classical
mechanistic approach of heat transfer, along with a molecular approach of
diffusion-controlled dynamic surface tensions. A main feature of the model is a
suggested explanation of the non-monotonous (“S-shaped”) boiling curves. A
simple model of surface tension is developed. The model is based on the general
van der Waals fluid theory, and features a new equation of state, unique for a
liquid-vapor interfacial region. It is applied in conjunction with the gradient
theory, to predict surface tension. The predicted surface tension values are in
good agreement with experimental data, for a variety of fluids. The phenomenon of
drag reduction in walled turbulent flows of polymer solutions is theoretically
modeled. A new mechanistic model of a polymer molecule in a turbulent flow
field is suggested, according to which, an additional route of dissipation
exists. A novel approach is then illustrated, where this mechanistic model is
accounted for as a turbulent scale alteration, which enables the Reynolds
classical dimensional analysis of a turbulent boundary layer to apply.
Correct-form velocity profiles are obtained, and Virk’s asymptote and slope are
predicted. Drag - flow rate curves are also calculated. The onset of drag
reduction phenomenon is also explained by this model. A model of heater scaling
is suggested, as a coupled mass and heat diffusion process at the heater interface,
under the idealization of equilibrium dissolution conditions. Scaling rate is
concluded to depend on the Lewis number, temperature, and heat flux. Optimal
heating strategy (functional) to minimize heater scaling is computed.
