Gas turbine turboshaft engine

The invention discloses a gas turbine turboshaft engine. An engine body comprises a centrifugal compressor, a combustion chamber, an expansion vortex tube, a smoke collecting pipe, a gas feeding basin, a heat regeneration hood and a power output shaft; the heat regeneration hood is arranged outside the gas feeding basin, is connected with a heat source, can heat air and communicates with the gas feeding basin; during working, the air is sucked into a left side cavity of the heat regeneration hood through a heat exchange connector outside the smoke collecting pipe, and the fresh air subjected to heat regeneration is sucked into the centrifugal compressor from the gas feeding basin, is compressed and then enters the combustion chamber; the compressed air is ignited together with fuel oil input by an oil self-supplying input point, then the enthalpy value is increased, and smoke is sprayed through a nozzle of the combustion chamber to push the expansion vortex tube to rotate; the expansion vortex tube and the ce