Impact of variable thermal conductivity in doubly stratified chemically reactive flow subject to non-Fourier heat flux theory

•Doubly stratified stagnation point flow of second grade fluid is studied.•Stretching surface with variable thickness is studied.•A new concept of heat flux covering paradox of heat conduction i.e. Cattaneo-Christov heat flux model is imposed.•Temperature dependent thermal conductivity is considered to discuss the heat transfer analysis.•First order chemical reaction is addressed.

This attempt reports the influence of variable thermal conductivity over an impermeable surface stretching in a nonlinear manner. Flow formulation is developed considering stagnation point and rheological expressions of second grade liquid. Different from the traditional literature, a new concept of heat flux covering paradox of heat conduction is imposed. Such concept has been used in view of Cattaneo-Christov theory. Besides this first order chemical reaction and double stratification are also considered. The subjected problems are modeled first and then non-dimensionalized. Computations for highly nonlinear problems are presented. The derived expressions are acceptable for convergence. Velocity, temperature, concentration, skin friction and Sherwood number are described through graphs for meaningful discussion considering important variables. Our computed analysis reveals that impacts of local second grade parameter and ratio of velocities have similar behavior on velocity distribution. Moreover the consideration of variable thermal conductivity improves the temperature and associated thermal boundary layer thickness.