A turbomachine includes a compressor, a turbine operatively coupled to the compressor, and a combustion assembly fluidly linking the compressor and the turbine. The combustion assembly includes at least one injector having a burner tube including an outer wall portion and an inner wall portion that define a mixing zone. A swirler arranged within the mixing zone. The swirler includes a plurality of vanes, with at least one of the plurality of vanes having a wall section including an outer surface and an inner surface that define a hollow interior portion. An insert member is arranged within the hollow interior portion. The insert member includes at least one guide element that is disposed and configured to deliver a fluid flow to the hollow interior portion to flow over the wall section of the at least one of the plurality of vanes.