Ultrahigh-performance cooling is one of the essential requirements in the industrial technology. Hence, the new heat transfer fluid, hybrid nanofluid is introduced to increase the thermal conductivity of fluid and investigated with various physical parameters. The unsteady magnetohydrodynamics (MHD) flow of Casson hybrid nanofluid through two surfaces in a permeable medium with chemical reaction are explored. The hybrid nanoparticles of Alumina and Copper is dispersed in the base fluid of sodium alginate . The discretize equations are solved using similarity transformation and Keller-box methods. The comparison of the current results with the published results for validation is conducted and discovered in proper agreement. The impacts of squeeze, magnetic, porous media, chemical reaction, heat sink/source, and Soret and Dufour on behaviour and physical quantities of flow are discussed. The graphical results show the squeeze of two surfaces accelerates the fluid velocity near the upper plate region. Further, the velocity slowing down when and increases, and it elevates as and rises in the middle of channel. The increment of heat transfer rate and temperature of fluid is shown for increasing Ec, y and Du, and the opposite behaviour is discovered with raise in. The fluid concentration decreases and the mass transfer rate enhances for rising Sr. The concentration enhance and rate of mass transfer reduce with the constructive chemical reaction, whereas contrary effects is shown for destructive chemical reaction.

Over the past two decades, research on hybrid nanofluids has developed at a breakneck pace. Hybrid nanofluids are the potential fluids that outperform conventional nanofluids heat transfer fluids regarding thermophysical characteristics and thermal performance. Hybrid nanofluids are traditionally prepared by emulsifying each nanoparticle into the base fluid independently or diffusing both particles as a composite form into the base fluid. Despite the popularity and broad application of hybrid nanofluids in industrial/manufacturing processes, the review article classifying the mathematical models and categorization of the various hybrid nanofluids is limited in the scientific community. In light of this, this study examines recent and past research articles on deterministic hybrid nanofluid flow problems by exploiting different categorizations and metrics (method to solve the differential equation, the geometry of choice and thermophysical effects that have been employed as well as the nano-particle types). Researchers will be able to use the findings of this study for a future research proposal. Essentially, it is to fill in the gaps in the literature, particularly regarding the mathematical model for hybrid nanofluid flow problems and determining the geometry, thermophysical properties, and nanoparticle type.

The mixed convection flow and heat transfer of the hybrid nanofluid over a shrinking sheet are investigated. Molybdenum disulphide (MoS2) and graphene oxide (GO) are employed as two hybrid nanoparticles while engine oil (EO) as the base fluid is considered. In this study, the Reiner-Philippoff model as one of non-Newtonian types is deliberated since it has the ability to function on three distinct types of fluids: viscous, shear thickening and shear thinning. The Reiner-Philippoff relation, the momentum and energy equations under Tiwari and Das model are all employed in the study. Influences from mass flux are also considered in the flow. Before computation using the bvp4c function in MATLAB, the respected equations are first converted into ordinary differential equation form using the similarity transformation. When the established and current models are discovered to be identical in a specific case, a direct comparative investigation is conducted to confirm the correctness of the current model. In addition, the present results are shown graphically and in tabular form. It is hypothesized that the presence of a hybrid nanofluid significantly affects the fluid characteristic and gives more satisfactory results than a single nanofluid. The skin friction coefficient and heat transfer rate of hybrid nanofluids are greater than the nanofluids. In terms of velocity and temperature profile, the reduction in velocity and the enhancement in temperature profile are caused by a rise in the Reiner-Philippoff parameter. The same outcome is also seen when the volume fraction of hybrid nanofluids increases.

The demand on the complex model on the study of fluid flow problem is crucial since the real fluid exist in industry applications cannot be presented by the conventional fluid anymore due to the complex properties of the materials. Since then, many mathematicians and scientist try to create the model that can be presented those fluids. Fluid which having characteristics viscous and elasticity can be categorized as non-Newtonian type of fluid due to its relations which against Newton’s Law of viscosity. The application of the fluid is widespread in industrial applications including oils and gas sectors, the automobile industry and manufacturing processes. Paints is one of the examples of viscoelastic fluid since almost wall is painted by the materials polymer and solvents. Therefore, this work is intended to investigate the viscoelastic fluid flow with the porosity condition which then called as Brinkman-viscoelastic model. The flow is presumed to transfer over a geometry horizontal circular cylinder (HCC). The thermal boundary condition is set to be constant wall temperature (CWT). The governing equations which based on Navier Stokes equations are first transformed to the less complex form by utilizing a non-dimensionless and a non-similarity variable. The resulting equations were obtained in the partial differential equations (PDEs) and at the lower stagnation point case, the model is reduced to the ordinary differential equations (ODEs). The Keller-box method (KBM) is applied to solved the final equations. The validation process is performed by direct comparing with the established output in literature and found to be in a very strong agreement. This process is valid since the present model can be reduced to the previous model at the limiting case where the identical equations were obtained. The results of the present model are then computed and presented in tabular form and also illustrated in graphical form. It is noticed that the viscoelastic parameter and Brinkman Parameter significantly affected the fluid flow characteristics.

The investigation on the Reiner–Philippoff fluid model embedded with two different nanoparticles (Al2O3 and Cu) over a shrinking sheet is carried out. The Tiwari and Das model are applied in the study covering the continuity, momentum, energy equations, and Reiner-Philippoff relation. The flow studied also considers the mixed convection and mass flux influences. The respective equations are first transformed into ordinary differential equation form using the similarity transformation before performing the computation work using the bvp4c function in MATLAB. The present model is identical to the established model in special cases, and then a direct comparative study is executed to verify the current model. The results for respective problems are presented in tabular and graphical form. It is perceived that the presence of nanoparticles affects the fluid characteristic significantly.

In this study, the combined convective transport of Williamson hybrid nanofluid flow over a shrinking sheet containing Alumina (Al₂O₃) and Copper (Cu) nanoparticles with Engine Oil (EO) as its base fluid is investigated. The mathematical model is converted to similarity equations by suitable transformations. The bvp4c function in MATLAB is utilized to solve the similarity equations numerically. The comparison of the present model with the established model for verification purposes shows a reasonable agreement. The influences of several fluid parameters on the fluid flow behaviour are analysed. Outcomes reveal the increment in combined convective transport and suction parameter improve the performance of heat transport of the fluid. Furthermore, the non-Newtonian Williamson hybrid nanofluid provided better heat transport performance compared to nanofluid with the same value of nanoparticle concentration.