Abstarct: Today, thermal power plants meet the world's greatest energy needs. One way to increase the thermal efficiency of gas power plants is to raise the temperature of the hot gas entering the gas turbine. But the temperature tolerance level of the blade alloy limits the temperature of the gas entering the turbine. Therefore, to increase the temperature of the inlet gas to the turbine, it is necessary to use methods for cooling the turbine blades. Film cooling is an effective way to protect the surface of gas turbine blades from passing hot gases. One of the most important parameters affecting the film cooling, is the geometry of the cooling holes located on the blades. Therefore, in this dissertation, in the first part, the geometry of cooling holes is investigated using four types of cooling holes, namely 1) circular 2) fan shape 3) circular with lateral expansion and 4) circular with two outlet ducts, and in the second part We investigated the effect of swirl cooling flow on film cooling for circular, fan-shaped and circular modes with lateral expansion. The turbulence model used is also the K-ω SST model. According to the simulation results at blowing ratio 1, in circular holes with simple lateral expansion without swirl of the cooling flow, the intensity of the counter-rotating vortices formed in the center of the holes is reduced and the penetration of the cooling jet into the hot gas flow is less than in other cases. But the swirl cooling flow in the circular holes with lateral expansion has an adverse effect and leads to a 33% reduction in cooling efficiency. However, in circular and fan-shaped holes, swirl of the cooling flow at the inlet of the cooling holes leads to more diffusion of the cooling jet in the transverse direction. On average, the film cooling efficiency increases by 16% in the case of swirl cooling flow in circular holes and by 8% in fan-shaped holes at a distance between 0<x/d< 10 from the flat plate But at a distance of 10<x/d< 20 in the fanshaped holes, the cooling jet rises from the surface and increases the surface temperature, which in total leads to an average reduction of 4% in cooling efficiency. In circular holes with two outlet, the simulated results for the swirl case showed a 48% increase in the film cooling effectiveness compared to the simple mode. However, by increasing the blowing ratio to 1.5, the swirl cooling flow in the circular and fan-shaped cooling holes had very good results, so that in circular holes, on average, the film cooling effectiveness in the swirl flow case increased by 50% compared to the simple case. It is found that in the simple case, increasing the blowing ratio leads to the separation of the cooling jet from the surface, which is not seen in the cyclonic case. Also, the film cooling effectiveness for the fan-shaped holes increases by 42% in the swirl case compared to the simple case. But in general, the results of numerical simulation indicate that increasing the cross-sectional opening in the lateral direction in circular holes leads to more diffusion of cooling fluid, but the effect of swirl flow in this geometry is not favorable and increasing the blowing ratio by 1.5 reduces the effectiveness by 36%.