Naveen Kumar Gupta

The performance characteristics of a novel solar water desalination system has been inves-tigated experimentally. The desalination unit consisted of a square basin-pyramid solar still coupled with a solar heater. Different DI water based mono and hybrid nanofluids were pre-pared using CuO and GO nanoparticles following the two-step method. DI water when em-ployed as the heat transfer fluid in the system, improved the distillate water yield by about 28.80% relative to the conventional solar still. Out of all the considered CuO mono-nano-fluids, the 1.0 wt.% concentration resulted in the maximum increment of about 78.80% in the distillate water yield followed by 1.5 wt.% (62.05%) and 0.5 wt.% (53.30%) respectively. Utilizing the CuO+GO hybrid nanofluid, resulted in maximum increment of about 127.46% at 25:75 nanoparticle proportion followed by, 50:50 (101.33%) and 75:25 (89.30%) respectively, while employing the 1.0 wt.% GO mono-nanofluid, resulted in an increment of about 54.93% in the distillate water yield. The pumping power of the prepared nanofluids was found to be the function of their concentration. Hence, the performance index was evaluated for all the tested heat transfer fluids followed by an economic analysis of all the considered cases. The pu-rity of the produced distilled water was also assessed by comparing with the Bureau of Indian Standards. Finally, the study proposed the best suitable heat transfer fluid for the investigated system and suggested the possible futuristic research objectives.

The steady-state performance characteristics of a mesh-wick heat pipe were investigated ex- perimentally across a heat load range of 25W-100W incorporating DI water, Al2O3 nanofluids, and Al2O3+GO hybrid nanofluids respectively. All the nano-suspensions were prepared fol-lowing the two-step preparation method. Out of all the prepared Al2O3 nanofluids, 1.0 vol.% Al2O3 nanofluid exhibited the highest reduction in adiabatic vapor temperature. The hybrid combination of 75% Al2O3 +25% GO nanofluid in the heat pipe resulted in a maximum dec-rement of about 21.4%, and 59.5% in the average evaporator temperature, and thermal resis-tance respectively while offering maximum thermal efficiency enhancement of about 31.4% relative to the base fluid. The 75% Al2O3+25% GO hybrid nanofluid in the heat pipe offered the least thermal resistance at a gravity-assisted inclination of 60º. The current study contem- plates the most favourable hybrid combination of Al2O3 and GO nanoparticles for its incor-poration in the heat pipe and tries to identify the underlying reasons behind the performance characteristics achieved using hybrid nanofluids and finally projects the future research scope.

Energy losses of flowing air through solar air heater (SAH) duct does not consider in the ther-mal performance. Therefore, thermohydraulic performance based on exergetic efficiencies is a tool to assess the performance by considering energy losses in propelling the air simul-taneously to identify the best ribs configuration. This paper presents the thermohydraulic performance of SAHs exploiting various ribs roughness’s. The performance of SAHs is based exergetic evaluation based on IInd law of efficiency is most suitable for design of artificial-ly roughened SAH as it includes both requirement of pumping power and effective energy output. In this paper exergetic evaluation of differently roughened SAH has been done. The exergy efficiency of roughened SAH was calculated analytically with the help of correlations developed by researchers and the results also compared with conventional SAH under same operating parameters. The thermal and exergy efficiency curve as a function of temperature rise parameter (ΔT/I) has been plotted. As a results, hybrid ribs configuration exhibited the highest exergetic efficiencies when temperature rise parameters greater than 0.01 K.m/W, however, smooth duct also showed a significant exergetic efficiency when temperature rise parameters had low values.

Heat pipes are the specific class of heat exchangers. They are used in thermal management of electronic components. Research community is continuously working to obtain the optimum heat transfer performance. In present work, parametric study of heat pipe using nano- fluid has been carried out. The operating parameters of heat pipe like power supply, orientation (gravity assisted angle), filling- ratio, and nano-fluids concentration are being investigated to find the optimum thermal performance of heat pipe. Response surface method (RSM) is used to analyze the effect of operating parameters on thermal performance. The optimum value of thermal resistance and thermal efficiency are 0.3994 °C/Watt and 68.44% respectively. Most suitable power supply, inclination angle, filling ratio and nanofluid concentration are 185.85 W, 60.09°, 50.7% and 1.05 % respectively. The experimental results confirm and validate the RSM predicted results.

The goal of this research is to convey an outlook of heat transfer and friction factor in an exper-imental study with a double-pipe heat exchanger (DPHE). In process heat transformation (HT) and friction factor(f) in a DPHE counter-flow with a twisted tape (TT) arrangement by dimple inserts. The grooves were a kind of concavity that enhanced thermal transfer while only slightly degrading pressure. Heat transmission (HT) and friction factor(f) were investigated employing dimples with twisting tape of varying diameters along with uniform diameter (D) to the diameter-to-depth ratio (D/H). The impact of using twisted tape with various dimpled diameters D = 2, 4, and 6 mm at a uniform (D/H) = 1.5, 3 and 4.5 on heat transmission and friction factor properties were discussed. The dimple diameter (D) was directly connected to the friction coefficient (f), hence the highest value of friction factor was established at (D) = 6 mm. Furthermore, the best performance of Nusselt number (Nu) and performance evaluation criteria (PEC) was determined at a diameter of 4 mm. As a result, dimpled twisted tape additions are an excellent and cost-effective approach to improve heat transformation in heat exchangers. With fluid as a water, lower parameters, and higher Reynolds number (Re) resulted in better thermal conditions. Thermal performance and friction factor(f) correlations were developed with regard to the ge-ometry of the dimple diameter (D), its ratio (D/H), ‘Re’, and a good correspondence with the experimental data was achieved. The novel geometry caused a smaller pressure drop despite its higher convection heat transfer coefficient. The results also showed that raising the ‘Re’ and nanofluid concentration, the pressure drop increased.

In this study, the effect of different concentration of the Aluminium oxide-based nanofluid on the performance of Solar Desalination system was discussed. The Aluminium Oxide was used in different concentrations 1%, 2% and 6% on weight basis. The flow rate was also varied and its effect on the system efficiency was discussed. The nanofluid was compared with the water and there was improvement occurred in the efficiency during variation of incident radiation. With an increase in the concentration of Aluminium oxide nanoparticles, improvement in the efficiency was attained. More efficiency was attained at 6% nanoparticles addition with compared to 1% and 2%. With an increase in mass flow rate of the fluid, the nanofluid also showed better performance in terms of improvement in the efficiency.

This paper presents a study of the effect of nanofluids on the thermal performance of heat pipes in addition to a study of the operating limitations. This revie

In this research work, environmental monitoring processes and assessments are carried out by the modeling and analysis of the water quality of the Chambal River in the state of Rajasthan. Various samples were collected from different locations along the course of the river flow. This water is used for different kinds of human, animal, and agriculture corp. activities. Comparative analyses were conducted on the water parameters, viz. biochemical oxygen demand, chemical oxygen demand, dissolved oxygen, total coliform, and conductivity, for the of consecutive years 2020 and 2021. A model was developed with the help of MATLAB Simulink software (Version R2019a) to find the causes of oxygen deficiency and reoxygenation in water with time and distance. The results of two consecutive years help to predict the responsible factors for the degradation of the river’s water quality. The water quality modeling and simulation results conclude that the water quality of the Chambal River flowing through Rajasthan can rejuvenate itself during an alarming oxygen deficit within a short period. According to the results of this study, the concentration of dissolved oxygen in the water of the Chambal River is high enough to support the survival of the endangered species that inhabit the area.

Electronic gadgets have been designed to incorporating very small components such as microcontrollers, electronic chips, transistors, microprocessors, etc. These components are exceptionally heat sensitive and can be wrecked if heat is not released. As a result, the thermal control of such components is critical to their optimum performance and extended life. The use of a microchannel heat sink (MCHS) has shown promising solutions to remove the excess heat. In this paper, we have proposed a novel design of MCHS and investigated it numerically. Four different surface modifications on the sidewall of the passage, namely, extended triangular surface (ETS), extended circular surface (ECS), triangular groove surface (TGS), and the circular groove surface (CGS) in the passage of the microchannel have been exploited in the Reynolds number of 100–900. In the presence of geometrical modification, the cooling capacities have been enhanced. The results show that the Nusselt numbers of ETS-MCHS, ECS-MCHS, TGS-MCHS, and CGS-MCHS are increased by 4.30, 3.61, 1.62, and 1.41 times in comparison to the Nusselt number of MCHS with smooth passage, while the friction factor values are increased by 7.33, 6.03, 2.74, and 1.68 times, respectively. In addition, the thermohydraulic performance parameter (THPP) has been evaluated and discussed. The fact that MCHS have THPP values greater than unity demonstrates that the passage’s geometries are a practical means of achieving effective thermal management.