The invention discloses an ultrahigh-rotating-speed
methane electric pump adopting internal flow
regenerative cooling. The ultrahigh-rotating-speed
methane electric pump comprises a
turbine pump, a motor and a
backflow pipe. The
turbine pump comprises a flow guide
pipe, a main
impeller, a pump shell and a pump cover. The main
impeller is rotationally arranged in the pump shell, a gap is reserved between the lower end of the main
impeller and the bottom of the inner wall of the pump shell, and a plurality of backpressure blades are arranged on the lower end face of the main impeller. The motor comprises a shell, a cover, a main shaft, a
stator and a rotor; a
machine cover is arranged at the upper end of the
machine shell, a first bearing seat with a first overflowing hole is arranged in the
machine cover, a second bearing seat with a second overflowing hole is arranged in the machine shell, and the main shaft is in running fit with the first bearing seat and the second bearing seat. The
backflow pipe is connected between the bottom of the machine shell and the flow guide pipe. According to the device, a same-working-medium internal flow regeneration cooling mode is adopted, so that a part of
methane fluid pressurized by the
turbine pump can flow to the motor to cool the motor and then flow back to the turbine pump, and the problem that the motor is seriously heated when working at a high rotating speed for a long time is effectively solved.