Impacts of surface roughness on mixed convection nanofluid flow with liquid hydrogen/nitrogen diffusion

Purpose The purpose of this paper is to present the surface roughness effects on mixed convection nanofluid flow with liquid hydrogen/liquid nitrogen diffusion. Design/methodology/approach The small parameter (alpha) is considered along with the frequency parameter n to study the surface roughness. The non-similar transformations are used to reduce the dimensional non-linear partial differential equations into dimensionless form, and then, the resulting equations are solved with the help of Newton's Quasilinearization technique and the finite difference scheme. Findings The impacts of several dimensionless parameters such as Brownian diffusion parameter (Nb), thermophoresis parameter (Nt), small parameter (alpha), etc., are analyzed over various profiles as well as gradients. Also, the investigation is carried out for in presence and absence of nanoparticles. The influence of surface roughness is sinusoidal in nature and is more significant near the origin in case of skin-friction coefficient. The addition of nanoparticles enhances the skin-friction coefficient and reduces the Nusselt number, while its effects are not noticeable in case of mass transfer rates. The presence of suction/blowing, respectively, enhances/decreases the Sherwood number pertaining to the liquid hydrogen. Practical implications The results of the present analysis are expected to be useful for the design engineers of polymer industries in manufacturing good quality polymer sheets. Originality/value To the best of the author's knowledge, no such investigation has been carried out in the literature.