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The use of renewable energy sources is leading the charge to solve the world’s energy problems, and non-Newtonian nanofluid dynamics play a significant role in applications such as expanding solar sheets, which are examined in this paper, along with the impacts of activation energy and solar radiation. We solve physical flow issues using partial differential equations and models like Casson, Williamson, and Prandtl. To get numerical solutions, we first apply a transformation to make these equations ordinary differential equations, and then we use the MATLAB-integrated bvp4c methodology. Through the examination of dimensionless velocity, concentration, and temperature functions under varied parameters, our work explores the physical properties of nanofluids. In addition to numerical and tabular studies of the skin friction coefficient, Sherwood number, and local Nusselt number, important components of the flow field are graphically shown and analyzed. Consistent with previous research, this work adds important new information to the continuing conversation in this area. Through the examination of dimensionless velocity, concentration, and temperature functions under varied parameters, our work explores the physical properties of nanofluids. Comparing the Casson nanofluid to the Williamson and Prandtl nanofluids, it is found that the former has a lower velocity. Compared to Casson and Williamson nanofluid, Prandtl nanofluid advanced in heat flux more quickly. The transfer of heat rates are 25.87 % , 33.61 % and 40.52 % at R d = 0.5 , R d = 1.0 , and R d = 1.5 , respectively. The heat transfer rate is increased by 6.91 % as the value of Rd rises from 1.0 to 1.5. This study is further strengthened by a comparative analysis with previous research, which is complemented by an extensive table of comparisons for a full evaluation.

The aim of this paper is to examine the effects of Cu–Al 2 O 3 /water hybrid nanofluid and Al 2 O 3 /water nanofluid on the mixed convection inside a square cavity caused by a hot oscillating cylinder. The governing equations are first transformed into dimensionless form and then discretized over a non-uniform unstructured moving grid with triangular elements. The effects of several parameters, such as the nanoparticle volume fraction, the Rayleigh number, the amplitude of the oscillation, and the period of the oscillation of the cylinder are investigated numerically. The results indicate that the motion of the oscillating cylinder toward the top and bottom walls increases the average Nusselt number when the Rayleigh number is low. Furthermore, the presence of Al 2 O 3 and Cu–Al 2 O 3 nanoparticles leads to an increase in the values of the average Nusselt number Nu avg for cases of low values of the Rayleigh number. It is found that the natural convection heat transfer rate of a simple Al 2 O 3 /water nanofluid is better than that of Cu–Al 2 O 3 /water hybrid nanofluid.

Owing to superior physio-chemical characteristics, titanium alloys are widely adopted in numerous fields such as medical, aerospace, and military applications. However, titanium alloys have poor machinability due to its low thermal conductivity which results in high temperature during machining. Numerous lubrication and cooling techniques have already been employed to reduce the harmful environmental footprints and temperature elevation and to improve the machining of titanium alloys. In this current work, an attempt has been made to evaluate the effectiveness of two cooling and lubrication techniques namely cryogenic cooling and hybrid nanoadditive–based minimum quantity lubrication (MQL). The key objective of this experimental research is to compare the influence of cryogenic CO 2 and hybrid nanofluid–based MQL techniques for turning Ti–6Al–4V. The used hybrid nanofluid is alumina (Al 2 O 3 ) with multi-walled carbon nanotubes (MWCNTs) dispersed in vegetable oil. Taguchi-based L9 orthogonal-array was used for the design of the experiment. The design variables were cutting speed, feed rate, and cooling technique. Results showed that the hybrid nanoadditives reduced the average surface roughness by 8.72%, cutting force by 11.8%, and increased the tool life by 23% in comparison with the cryogenic cooling. Nevertheless, the cryogenic technique showed a reduction of 11.2% in cutting temperature compared to the MQL-hybrid nanofluids at low and high levels of cutting speed and feed rate. In this regard, a milestone has been achieved by implementing two different sustainable cooling/lubrication techniques.

Cooling by impinging droplets has been the subject of several studies for decades and still is, and, in the last few years, the potential heat transfer enhancement obtained thanks to nanofluids’ use has received increased interest. Indeed, the use of high thermal conductivity fluids, such as nanofluids’, is considered today as a possible way to strongly enhance this heat transfer process. This enhancement is related to several physical mechanisms. It is linked to the nanofluids’ rheology, their degree of stabilization, and how the presence of the nanoparticles impact the droplet/substrate dynamics. Although there are several articles on droplet impact dynamics and nanofluid heat transfer enhancement, there is a lack of review studies that couple these two topics. As such, this review aims to provide an analysis of the available literature dedicated to the dynamics between a single nanofluid droplet and a hot substrate, and the consequent enhancement or reduction of heat transfer. Finally, we also conduct a review of the available publications on nanofluids spray cooling. Although using nanofluids in spray cooling may seem a promising option, the few works present in the literature are not yet conclusive, and the mechanism of enhancement needs to be clarified.

Nanofluids hold paramount importance in various fields, notably in thermal engineering, due to their exceptional thermal conductivity and heat transfer properties. This heightened efficiency makes nanofluids invaluable in enhancing the performance of cooling systems, heating processes, and thermal management applications. Keeping in view these important applications, this study involves the analysis of ternary hybrid nanofluid containing Cu , TiO 2 , and SiO 2 in water on a porous stretchy three-dimensional surface incorporating thermal radiation, thermophoretic forces, chemical reaction, Joule heating with convective and mass flux conditions. The leading equations rendered to dimensionless notation through the application of similarity transformation. Subsequently, the solution to the transformed equation is acquired using the bvp4c method. As outcome of the work, an elevated thermophoresis factor leads to an expansion of the concentration, whereas a lessening tendency is noted for Schmidt number, Brownian motion and chemical reactivity factor. The thermal efficiency of the ternary nanofluid is enhanced by factors such as thermophoresis thermal radiation, Biot number, Eckert number, and magnetic field. The computed estimates of drag force at surface reveal the impact of various parameters, indicating that an increase in the porosity parameter leads to a reduction in the surface drag force in x - as well as y - directions. Conversely, advancement in the magnetic factor causes an escalation in surface drags force along the y - direction. Higher Biot number and radiation parameter values enhance the heat transference proportion, whereas higher Brownian motion, thermophoresis, and Eckert number decrease the thermal flow rate. Additionally, escalation in chemical reaction, Schmidt number, and Brownian motions enhances the mass transfer rate. The numerical code for this work has satisfactory promise with the already published work. The insights gained from this analysis can be applied to enhance the efficiency of engineering processes where convective heat transfer is a critical factor, thereby improving the performance of various applications like cooling systems, heat exchangers, and other thermal management systems. The research findings have practical implications for industries seeking to optimize energy utilization and improve the thermal performance of their systems through the utilization of advanced nanofluid dynamics.

In the present study, heat transfer and fluid flow of a pseudo-plastic non-Newtonian nanofluid over permeable surface has been solved in the presence of injection and suction. Similarity solution method is utilized to convert the governing partial differential equations into ordinary differential equations, which then is solved numerically using Runge–Kutta–Fehlberg fourth–fifth order (RKF45) method. The Cu, CuO, TiO 2 and Al 2 O 3 nanoparticles are considered in this study along with sodium carboxymethyl cellulose (CMC)/water as base fluid. Validation has been done with former numerical results. The influence of power-law index, volume fraction of nanoparticles, nanoparticles type and permeability parameter on nanofluid flow and heat transfer was investigated. The results of the study illustrated that the flow and heat transfer of non-Newtonian nanofluid in the presence of suction and injection has different behaviors. For injection and the impermeable plate, the non-Newtonian nanofluid shows a better heat transfer performance compared to Newtonian nanofluid. However, changing the type of nanoparticles has a more intense influence on heat transfer process during suction. It was also observed that in injection, contrary to the other two cases, the usage of non-Newtonian nanofluid can decrease heat transfer in all cases.

In the current study, heat transfer performances and flow characteristics of alumina–copper/water (Al 2 O 3 –Cu/H 2 O) hybrid nanofluid over a stretching cylinder are explored under the influence of Lorentz magnetic forces and thermal radiation. The Roseland’s flux model is employed for the impact of thermal radiations. The governing flow problem comprises of nonlinear ordinary differential equations, which are transformed into nondimensional form via suitable similarity transforms, Boussinesq and boundary layer approximations. Results of heat and fluid flow as well as convective heat transfer coefficient and skin friction coefficient under influence of embedding parameters are displayed and discussed through tables and graphs. To check its heat transfer performance, a comparison of hybrid nanofluid with base fluid and single material nanofluids is also made and found that hybrid nanofluids are more effective in heat transfer than conventional fluids or single nanoparticles-based nanofluids.

The aim of the present study is to investigate the effects of a hybrid nanofluid in a square cavity that is divided into two equal parts by a vertical flexible partition in the presence of a magnetic field. A numerical method called the Galerkin finite element method is utilized to solve the governing equations. The effects of different parameters, namely the Rayleigh number (10 6  ≤  Ra  ≤ 10 8 ) and the Hartmann number (0.0 ≤  Ha  ≤ 200) as well as the effects of nanoparticles concentration (0.0 ≤  φ  ≤ 0.02) and magnetic field orientation (0 ≤  γ  ≤  π ), on the flow and heat transfer fields for the cases of pure fluid, nanofluid and hybrid nanofluid are investigated. The results indicate that the streamline patterns change remarkably and the convective heat transfer augments with increasing values of the Rayleigh number. Additionally, the maximum stress imposed on the flexible partition resulting from the interaction of the partition and pure fluid is more than those caused by the nanofluid and the hybrid nanofluid. Furthermore, the increase in the magnetic field strength decreases the fluid velocity in the cavity, which declines the fluid thermal mixing and heat transfer effects.