Forced Convective Heat Transfer of MWCNT/Water Nanofluid Under Constant Heat Flux: An Experimental Investigation

Abstract

This research article investigates the effect of multi-walled carbon nanotubes (MWCNT)/water nanofluid on convective heat transfer in a uniformly heated copper tube under laminar flow regime. The MWCNT were synthesized using chemical vapor deposition method and characterized using transmission electron microscope. These nanoparticles were dispersed (with 0.05, 0.1, 0.3 and 0.5 % weight concentrations) in distilled water to form stable suspensions of nanofluids. The heat transfer coefficients (HTC) of nanofluids and distilled water (base fluid) were evaluated and compared using constant velocity basis. The thermophysical properties of nanofluids change with the addition of nanoparticles; thus, we have considered the constant velocity criteria which provide the true comparison in contrast to constant Reynolds number used by earlier researchers. The effect of flow velocity (0.166-0.232 m/s) and nanoparticles weight concentration on the HTC considering constant heat flux boundary conditions was studied. It is observed that with the increase in the weight concentration of nanoparticles or flow velocity, the HTC increases. Nanofluids show higher HTC with respect to distilled water at all the concentrations of nanoparticles. At 0.5 wt.% weight concentration and flow velocity of 0.232 m/s, the maximum HTC obtained is 77.60 % in comparison with distilled water. B Munish Gupta

Experimental Investigations of Forced Convection of Nanofluids in Smooth, Horizontal, Round Tubes: A Review

“…Local HTC in research by Esmaeilzadeh et al [98] is much lower than that of Almohammadi et al [85], although tests were carried out on the same test stand. Lower local HTC for study by Esmaeilzadeh et al [98] may be due to the fact that they refer to a greater dimensionless distance from the inlet, and it is known that local HTC decreases with increasing x/D [43,48,53,57,80,86,88,92,101,115,126,131,134,144]. Moreover, according to a study by Anoop et al [54], the smaller the diameter of the NPs, the higher the local HTC.…”

“…The highest increases in both HTC and Nu number were observed for the minimum tested Re number, and were 57% and 27%, respectively. Gupta et al [131] found that HTC increased with increasing velocity, NPs concentration, and heat flux, while the effect of velocity for the same NPs concentration was small. The maximum HTC enhancement was about 78% for the highest NPs concentration and heat flux.…”

Numerical study on CNT nanofluids behavior in laminar pipe flow

“…rate was lowered by the presence of nanotubes. CHT in uniformly heated copper tube of MWCNT/water nanofluids under laminar regime was also investigated by Gupta et al [13].…”

Heat transfer augmentation in a tube using nanofluids under constant heat flux boundary condition: A review

“…Convective heat transfer of multi-walled carbon nanotubes (MWCNT)/water nanofluid inside an evenly heated copper tube with laminar flow was performed experimentally by Gupta et al [51]. Synthesis of MWCNT particles was done using CVD method and characterization was done by using TEM (transmission electron microscope).Weight concentrations of 0.05, 0.1, 0.3 and 0.5% were used to obtain stable solutions.…”