calculation of heat transfer coefficient of mwcnt-tio2 nanofluid in plate heat exchanger

the objective of the present study is the synthesis of mwcnt-tio2 hybrid nanostructures by solvothermal synthesis method with ticl4 as precursor. the heat transfer enhancement due to the use of mwcnt-tio2 nanofluid was investigated. as-prepared hybrid materials were characterized by x-ray diffraction (xrd) and scanning electron microscopy (sem). the results showed that mwcnts were uniformly decorated with anatase nanocrystals. the heat transfer performance of the plate heat exchanger (phe) was investigated using mwcnt-tio2 nanofluid at various volume flow rates, a wide range of concentrations and inlet temperatures. the performance is discussed in terms of heat transfer coefficient ratio. the results showed that the heat transfer coefficient of the nanofluid was more than that of the base fluid (distilled water). the heat transfer coefficient was enhanced with increasing the nanofluid concentration from 0.02 to 0.08 wt.% and volume flow rate from 2 to 3.5 lpm. conversely, the heat transfer coefficient decreased with increasing the nanofluid inlet temperature from 36 to 60oc.