A turbine rotor disk with a turbine blade, the rotor disk having a cooling air feed channel to force cooling air into an internal cooling air passage within the turbine blade, the feed channel including a swirl generator at the inlet end to promote a swirling motion within the cooling air, and the feed channel including a helical rib extending from the swirl generator to the outlet of the feed channel to maintain the swirling motion of the cooling air within the feed channel such that dirt particles in the cooling air are collected within the center of the swirling air flow. The feed channel directs the swirling cooling air into a first passage of the internal serpentine flow cooling circuit of the blade. A cooling air exit hole is located at the blade tip and is aligned with the cooling air flow in the first passage. The swirling air flow with the collected dirt particles ejects the dirt particles out through the exit hole while the clean cooling air continues through the serpentine flow circuit to provide cooling for the blade.