Consequently, the boiling curve can be drawn as a function of local values of the heat transfer coefficient (or heat flux) and wall superheat
from equation (i).
Furthermore, an understanding of the effects that varying wall superheat values have on the ratio of sensible to evaporative heat transfer is critical to optimizing the falling film heat exchanger.
Also, this investigation defines tube wall superheat as the difference between the inlet heating fluid temperature and saturation temperature of the system.
This is ideal because, due to the counter-flow design of the heating and solution fluid lines, the bottommost row always has the highest wall superheat and therefore produces the greatest evaporative heat transfer.
The tube wall superheat also contributes to the overall ratio of evaporative-to-sensible heat transfer in the falling-film heat exchanger.
The data also show a larger increase in heat duty between 10 and 15[degrees]C wall superheat than there is between 5 and 10[degrees]C.
1]] Subscripts c column d hydraulic diameter ds solution dispenser eva evaporation h heating fluid i inlet lv liquid-vapor nz solution dispenser nozzle hole o outlet or outer s solution or sensible sat saturation sc subcooling sh wall superheat t tube or thermal tot total v vapor Greek symbols [delta] boundary layer thickness [m] [GAMMA] solution mass flow rate per unit length and per side [kg-[s.
Because the liquid is saturated at toe vapor-liquid interface, a low effective thermal conductivity requires a large amount of wall superheat
which, in turn, causes the liquid to boil.
Upward facing surface of this wafer has been immersed in deionised water at atmospheric pressure and uniformly heated maintaining constant wall superheat by circulating fluid on its lower side (Fig.
Onset of nucleate boiling process occurs as wall superheat reaches the value of 19 [degrees]C.
Results that present the stages of ebullition cycle have been acquired at wall superheat value of [[DELTA]T.
The wall superheat
([DELTA]T) is defined as the difference between the wall temperature ([T.