A turbine wheel including a plurality of blades having roots engaged axially and held radially in slots in a disk alternating between teeth of the disk, in which the blades have platforms arranged circumferentially end to end and each connected to a blade root by a tang, is provided. Separator walls extend from the tangs in a circumferential direction and from upstream to downstream so as to define radially between the platforms and the teeth of the disk at least a radially inner cavity and a radially outer cavity between two adjacent tangs.