Disappearance of criticality for reactive third-grade fluid with Reynold's model viscosity in a flat channel

► In the study we examine reactive third-grade fluid with Reynold's viscosity. ► The corresponding coupled equations depend on five parameters: pressure drop, non-Newtonian coefficient, viscous heating parameter, viscosity parameter and numerical exponent. ► A numerical description highlighting the flow pattern, criticality and disappearance of criticality are discussed.