In this paper, the reasonable swirl cooling structures are established to study the effects of circumferential nozzle number and temperature ratio on swirl cooling. Numerical simulations are conducted by solving the Reynolds Averaged Navier-Stokes (RANS) equations and the standard k-ω turbulence model. Under the same coolant mass flow rate and nozzle aspect ratio, two swirl cooling models of keeping the nozzle geometry unchanged, and keeping the nozzle inlet total area unchanged are studied, respectively. Besides, effects of inlet to target wall temperature ratio on multiple circumferential jet nozzles configurations are involved in parametric studies. Results indicate that when keeping the nozzle geometry unchanged, the heat transfer intensity and total pressure penalty decrease with the increasing circumferential nozzle number. And the target Nusselt number distribution becomes more uniform. When keeping the nozzle inlet total area unchanged, the heat transfer intensity increases firstly and then decreases with the increase of circumferential nozzle number. Finally, it becomes the largest value at the circumferential nozzle number equaling two. Meanwhile, the total pressure loss increases with the increasing circumferential nozzle number. Overall, the configuration of the circumferential nozzle number equaling two has the optimum cooling efficiency. Additionally, the increase of temperature ratio contributes to a relatively higher Nusselt number and a lower heat flux. Compared with former studies, it suggests that different circumferential and axial jet nozzles may affect the influences of temperature ratio on swirl cooling performance.