Abstarct: Today, power plants provide the world's most pressing energy needs. One way to increase thermal efficiency in gas plants is to raise the temperature of the hot gas inlet to the gas turbine. Therefore, this research focuses on simulation and study of three-dimensional fluid flow and turbulent heat transfer, for internal cooling of the middle area (chord), fixed blades and rotating gas turbine by smooth and ribbed four-channel channels. In addition, by adding a combination of thermal performance enhancers to the serpentine cooling paths, including the addition of a turning vane and 45 degree round corner ribs to the mainstream, the thermal performance coefficient is investigated and improved. Equations governing the flow and heat transfer of cooling fluid using Fluent 17.2 software and using a Reynolds stress turbulence model in three Reynolds numbers in the range of 20,000 to 60,000 and four rotations in the range of 0.016 to 0.13 for two cooling chambers in steady state Done. According to the results, Reynolds stress turbulence model as a suitable turbulence model to validate and simulate the flow and heat transfer of selected Serpentine channels as well as the effect of turning vane on the bending area of the hub to increase the coefficient of cooling and internal cooling for smooth and smooth channels And has been able to increase these coefficients by up to 10% at their maximum for different states. In addition, the effect of rotational angle change on the axis of rotation from orthogonal to non-orthogonal is effective in Nusselt uniformity and to prevent thermal stress on the walls, but in general it will reduce the thermal performance coefficient by 37.80%.