Discrete heating action has been established as an energy efficient method. Nusselt number plays a significant role in the heat transfer rate. Local Nusselt number is useful in analyzing the heat transfer rate along the sections of the side walls with different or same temperature in a heated enclosed cavity. Whereas the average Nusselt number quantifies the total heat change in the closed cavity. While the path of the trajectory of the heat flow is being analyzed by heat function. In the current work, multiple heaters of length , and are assembled at each side of the isosceles triangle. The numerical simulations of the modeled system along with boundary conditions are carried out by using the standard Galerkin Finite Element Method. The nonlinear algebraic system is solved by Newton method. The behavior of fluid inside the closed triangle with is observed. The results are reported in terms of the graphs of the temperature contours, streamlines, average and local Nusselt numbers. The maximum heat transfer rate is observed in convection dominant case. By increasing the magnitude of a bi-viscosity parameter, secondary circulation is observed for The rate of heat transfer has a direct relation with the bi-viscosity parameter. The maximum values of average and local Nusselt numbers are achieved by using the heat generation parameter against the Grashof number.