Heat transfer intensification in heat exchangers can be achieved
by active, passive and compound heat transfer techniques. The
active techniques require external forces, e.g., electric field, surface
vibration, etc. The passive techniques require fluid additives (e.g.,
nanoparticles) or special surface geometries (e.g., helical coil). The
widely used conventional intensification techniques in process
industries are internal and external tube fins, twisted-tape inserts,
coiled-wire inserts, helical baffles and fluid additives. Helical
coiled tubes are used in many engineering applications, such as
heating, refrigeration and HVAC systems [1–3]. Helical coiled tubes
are also used in steam generators, nuclear reactors and condensers
in power plant due to their large surface area per unit volume.
Many researchers have experimentally investigated the heat
transfer in the helical coil heat exchanger [4–9]. They reported
that the heat transfer coefficients obtained from the coiled tube
were higher than those obtained from a straight tube.