Conclusions
From the study, the following conclusions may be drawn:
- In SMMHP, the terminal temperature difference is very high comparing
with that of in TMMHP. As a result, the h of the working fluid
produced by the SMMHP is much smaller than that of TMMHP.
- Out of four working fluids, methanol has been found to be of
the highest h because of its lowest boiling point that enables
quick completion of thermodynamic cycle.
- Out of three orientations, TMMHP at 45o produces the
highest value of h for all four fluids; however, the sequence
of h remains the same in all the orientations.
- It is proven that MHP made with the metals of variable thermal
conductivity (i.e.TMMHP) of ascending order orientation, which
initiates the super heater effect in the evaporator, indicates many
folds better prospect of h value than that of made with
constant conductivity (SMMHP).
- While an assumption of single phase flow in SMMHP works well at lower
heat inputs, but at moderately high heat inputs it becomes a two-phase
flow. However, the super heater effect at the evaporator in TMMHP
eliminates that complexity of the two-phase and instantly turns into a
single phase flow of vapor which was not possible in SMMHP [6, 7].
- In case of water, the upper trend of temperature at the condenser port
is uniquely different from that of other liquids. Such a condition
demands the coolant flow at lower than the ambient temperature or a
coolant of higher Cp. Eventually, the slightly
increased temperature of the vapor condensate speeds up the capillary
action of the wick.
- Even though the values of h in TMMHP are many times higher than
those of in SMMHP, the limitation of its value is obvious in both the
heat pipes at a relatively higher heat input.
- The change of any specific physical property (i.e. density, specific
gravity, viscosity) of a fluid singly cannot change the h of
that fluid in an MHP, rather it is a compound value developed
functionally from both of its physical properties and state variables.