No abstract

In this paper, three-dimensional simulations to study the performance of microchannel heat sinks (MCHS) with rectangular, hexagonal, semicircular and various novel cross section (such as barrel, fan shaped, L shaped, inverted T shaped, inverted T shaped with semicircular ends at base (ITSCEB)) were carried out using de-ionized water. Numerical results were validated with the published experimental data and further simulations were performed on various novel cross section at a constant heat flux of 50 W/cm2 with Reynolds number varying in the range of 300–1500. The comparative analysis of various novel MCHS having the same cross-sectional area was carried out to figure out the suitable cross section capable of better cooling performance. This work shows that the novel ITSCEB cross section was giving the highest pressure drop, however considerable improvement was noted in the heat transfer coefficient around 21% more than conventional rectangular and around 11–55% more than other proposed cross section in this study.

In this paper, the effect of chitosan surfactant concentration on the thermal conductivity and viscosity of Al2O3 + CNT/water hybrid nanofluid is reported. SEM was used to characterize the nanoparticles. The hybrid nanofluid of 0.01% volume fraction was prepared with 1:1 ratio of Al2O3& CNT nanoparticles. Different concentrations of chitosan surfactant as 0.25, 0.5, 0.75, 1.0, and, 1.25 wt.% are employed as stabilizers. Zeta potential measurements were carried out to check the stability of prepared hybrid nanofluid. Thermal conductivity and viscosity of hybrid nanofluid were measured at a constant temperature of 25°C. Finally, the optimum concentration of surfactant using the results obtained is determined.For the most stable suspension, thermal conductivity ratio is 1.0065 and viscosity is 30.2% more than that of the base fluid.

No abstract

No abstract