Intensified Thermal Conductivity and Convective Heat Transfer of Ultrasonically Prepared CuO–Polyaniline Nanocomposite Based Nanofluids in Helical Coil Heat Exchanger

In this study, investigation of convective heat transfer enhancement with the use of CuO–Polyaniline (CuO–PANI) nanocomposite basednanofluid inside vertical helically coiled tube heat exchanger was carried out experimentally. In these experiments, the effects of different parameters such as Reynolds number and volume % of CuO–PANI nanocomposite in nanofluid on the heat transfer coefficient of base fluid have been studied. In order to study the effect of CuO–PANI nanocomposite based nanofluid on heat transfer, CuO nanoparticles loaded in PANI were synthesized in the presence of ultrasound assisted environment at different loading concentration of CuO nanoparticles (1, 3 and 5 wt.%). Then the nanofluids were prepared at different concentrations of CuO–PANI nanocomposite using water as a base fluid. The 1 wt.% CuO–PANI nanocomposite was selected for the heat transfer study for nanofluid concentration in the range of 0.05 to 0.3 volume % and Reynolds number range of was 1080 to 2160 (±5). Around 37 % enhancement in the heat transfer coefficient was observed for 0.2 volume % of 1 wt.% CuO–PANI nanocomposite in the base fluid. In addition, significant enhancement in the heat transfer coefficient was observed with an increase in the Reynolds number and percentage loading of CuO nanoparticle in Polyaniline (PANI)

Sonochemical Formation of Peracetic Acid in Batch Reactor: Process Intensification and Kinetic Study

The present chapter highlights the kinetic studies for the sonochemical synthesis of peracetic acid (PAA) in a batch reactor. The effect of different operating parameters including acetic acid to hydrogen peroxide molar ratio, temperature, catalyst loading, effect of ultrasound, were studied using Amberlite IR-120H as a catalyst. The deactivation of the Amberlite IR-120H catalyst has also been studied. The experimental data were further utilized for the estimation of intrinsic reaction rate constants and equilibrium constants. From the experimental results; the optimized PAA concentration was observed for 471 mg/cm3 catalyst loading at 40°C with acetic acid to hydrogen peroxide molar ratio equals to 1:1 in the presence of ultrasound. Results also revealed that the reaction rate was found to be significantly enhanced in the presence of ultrasound, which can be attributed to the enhanced mixing and in-situ formation of H2O2. The use of ultrasound drastically reduces the overall reaction time to 60 min, which is very less compared to 30 h as reported for conventional batch reactor utilizing H2O2 only

Intensification of heat exchanger performance utilizing nanofluids

Heat exchangers are widely utilized in different thermal systems for diverse industrial aspects. The selection of HEx depends on the thermal efficiency, operating load, size, flexibility in operation, compatibility with working fluids, better temperature and flow controls, and comparatively low capital and maintenance costs. Heat transfer intensification of heat exchangers can be fulfilled using passive, active, or combined approaches. Utilizing nanofluids as working fluids for heat exchangers have evolved recently. The performance of heat exchangers employed different nanofluids depends mainly on the characteristics and improvement of thermophysical properties. Regarding the unique behavior of different nanofluids, researchers have attended noteworthy progress. The current study reviews and summarizes the recent implementations carried out on utilizing nanofluids in different types of heat exchangers, including plate heat exchangers, double-pipe heat exchangers, shell and tube heat exchangers, and cross-flow heat exchangers. The results showed that nanofluids with enhanced thermal conductivity, although accompanied by a considerable decrease in the heat capacity and raising viscosity, has resulted in performance enhancement of different heat exchangers types. So, the performance evaluation criterion that combines the thermal enhancement and increases the pumping power for any type of heat exchangers is requisite to evaluate the overall performance properly. The challenges and opportunities for future work of heat transfer and fluid flow for different types of heat exchangers utilizing nanofluids are discussed and presented