Numerical simulation of bioconvective peristaltic flow of saline-based hybrid nanofluid with second-order slip velocities through an endoscope under electroosmotic effects

This study focuses on developing a mathematical model for the bioconvective peristaltic propulsion of a saline-based hybrid nanofluid containing motile microorganisms through an endoscope. The flow phenomenon is further assisted by electroosmosis. Single-walled and multi-walled carbon nanotubes are employed to prepare the blood-based hybrid nanofluid. The modified Buongiorno model is utilized to incorporate the effects of nanotubes, with a comparison presented between two thermal conductivity models specified for nanotubes: the Xue model and the Yamada–Ota model. Furthermore, the energy equation is modified to include space- and temperature-dependent heat sources/sinks as well as Joule heating. Second-order slip boundary conditions for velocity are assumed at the outer wall of the endoscope. The formulated system of equations is nondimensionalized and simplified under the long-wavelength approximation. The resulting nonlinear and coupled differential equations are solved using the explicit Runge–Kutta method in Mathematica. Flow characteristics are analyzed graphically under varying parameter values, and it is observed that the Yamada–Ota model predicts enhanced thermal properties of the hybrid nanofluid more effectively. A decline in fluid velocity is observed with increasing bioconvective Rayleigh number. Moreover, increasing the oxygen consumption parameter by a factor of 2 results in a 6.69% decrease in oxygen concentration. When the fraction of nanotubes of both types increases from 1% to 2%, the Xue model predicts a 5.32% drop in temperature, whereas the Yamada–Ota model predicts a 6.94% drop.