The heat transmission capabilities of hybrid nanofluids are superior to those of mono nanofluids. In addition to solar collectors and military equipment, they may be found in a number of areas including heat exchanger, automotive industry, transformer cooling and electronic cooling. The purpose of this study was to evaluate the significance of the higher order chemical reaction parameter on the radiative flow of hybrid nanofluid (polyethylene glycol (PEG)–water combination: base fluid and zirconium dioxide, magnesium oxide: nanoparticles) via a curved shrinking sheet with viscous dissipation. Flow-driven equations were transformed into nonlinear ODEs using appropriate similarity transmutations, and then solved using the bvp4c solver (MATLAB built-in function). The results of two scenarios, $PEG-Water+Zr{O}_2+MgO$ (hybrid nanofluid) and $PEG-Water+Zr{O}_2$, (nanofluid) are reported. In order to draw important inferences about physical features, such as heat transfer rate, a correlation coefficient was used. The main findings of this study were that curvature parameter lowers fluid velocity, and Eckert number increases the temperature of fluid. It was observed that the volume fraction of nanoparticles enhances the skin friction coefficient and curvature parameter lessens the same. It was noticed that when curvature parameter (K) takes input in the range $0.5\le K\le 2.5$, the skin friction coefficient decreases at a rate of 1.46633 (i.e., 146.633%) (in the case of hybrid nanofluid) and 1.11236 (i.e., 111.236%) (in the case of nanofluid) per unit value of curvature parameter. Increasing rates in the skin friction parameter were 3.481179 (i.e., 348.1179%) (in the case of hybrid nanofluid) and 2.745679 (in the case of nanofluid) when the volume fraction of nanoparticle (${\varphi }_1$) takes input in the range $0\le {\varphi }_1\le 0.2$. It was detected that, when Eckert number $\left(E_{ck}\right)$ increases, Nusselt number decreases. The decrement rates were observed as 1.41148 (i.e., 141.148%) (in the case of hybrid nanofluid) and 1.15337 (i.e., 153.337%) (in the case of nanofluid) when Eckert number takes input in the range $0\le E_{ck}\le 0.2$. In case of hybrid nanofluid, it was discovered that the mass transfer rate increases at a rate of 1.497214 (i.e., 149.7214%) when chemical reaction $\left(Kr\right)$ takes input in the range $0\le Kr\le 0.2$. In addition, we checked our findings against those of other researchers and discovered a respectable degree of agreement.

In this new era of the fluid field, researchers are interested in hybrid nanofluids because of their thermal properties and potential, which are better than those of nanofluids when it comes to increasing the rate at which heat is transferred. Compared to the dynamics of radiative Ethylene Glycol-Zinc Oxide (nanofluid) and Ethylene Glycol-Zinc Oxide-Titanium Dioxide (hybrid nanofluid) flows between two permeable expanding/contracting walls, nothing is known in terms of Lorentz force, heat source, and the activation energy. The thermo-physical characteristics of Ethylene Glycol, Zinc Oxide nanoparticles, and Titanium Dioxide nanoparticles are used in this study to derive the governing equations for the transport of both dynamics. Governing equations are converted as a set of nonlinear ordinary differential equations (with the aid of suitable similarity mutations), and then the MATLAB bvp4c solver is used to solve the equations. This study’s significant findings are that rise in the reaction rate constant increases mass transfer rate, whereas an increase in the activation energy parameter decreases it. The mass transfer rate decreases at a rate of 0.04669 (in the case of hybrid nanofluid) and 0.04721 (in the case of nanofluid) when activation energy ($E$) takes input in the range $0\le E\le 5$. It has been noticed that the velocity profiles are greater when the walls are expanding as opposed to when they are contracting. It is detected that the heat transfer rate reduces as the heat source parameter increases. The heat transfer rate drops at a rate of 0.9734 (in the case of hybrid Nanofluid) and 0.97925 (in the case of nanofluid) when the heat source parameter ($Q$) takes input in the range $0\le Q\le 0.3$. In addition, it has been observed that the entropy generation increases as the Brinkmann number rises.

Fluid flow through a sphere has practical applications in numerous areas of technology, for instance, mineralogy, food engineering, and oilfield drilling. The goal of this paper is to look at how quadratic thermal radiation and activation energy affect the dissipative flow of hybrid nanofluids around a sphere with the heat source parameter. bvp4c (a MATLAB in-built function) is used to solve a system of nonlinear ordinary differential equations, which is the transformed version of the system of governing equations. Using multiple linear regression, the effects of relevant parameters on the mass transfer rate, the Nusselt number, and the skin friction coefficient are investigated. The key findings of this study are that increasing the radiation parameter improves the fluid temperature and increasing the activation energy parameter improves the fluid concentration. When the Eckert number and the parameter of the heat source are increased, the convective heat transmission is reduced. It appears that the magnetic field parameter reduces the shear stress near the surface. It is discovered that increasing the volume percentage of nanoparticles increases the skin friction coefficient and increasing the Schmidt number increases the mass transfer rate. Furthermore, the current results are validated against previously published data.