The current study inspects the radiative heat and mass transport of a polyalphaolefin (PAO) – based nanolubricant flow consisting of titanium dioxide (TiO2) nanoparticles in a convergent/divergent channel with thermophoresis, Brownian motion, and non-uniform heat source/sink effects. The mathematical modelling of the present problem results in a system of complex non-linear partial differential equations (PDEs). The Galerkin finite element method (GFEM) is adopted to solve complex equations and to obtain the solution for the field variables in convergent/divergent channels. The results revealed that as the values of Brownian motion get higher, the temperature dispersal in the channel quickens, whereas the concentration profile slows down. The rise in the value of the thermophoresis parameter increases the thermophoresis force, which causes liquid particles to be dispersed in the stream. The heat transmission rate increases with an increase in radiation parameter values.