Hydrogen recirculation ejector for fuel cells

A hydrogen recirculation ejector for fuel cells, the hydrogen recirculation ejector comprising:

• a recirculation line configured to recirculate residual hydrogen gas discharged from a fuel cell stack configured to generate electricity using air and hydrogen gas supplied thereto to an inlet of the fuel cell stack;
• and
• an ejector comprising a nozzle installed on the recirculation line, the nozzle being configured to supply new hydrogen gas, a venturi tube configured to mix the supplied new hydrogen gas from the nozzle and the recirculated residual hydrogen gas with each other, and a diffuser configured to supply the mixed hydrogen gases to the fuel cell stack, wherein
• the nozzle is inserted into and installed in an inlet of the venturi tube, and the nozzle comprises:
• a hydrogen introduction portion configured to allow hydrogen supplied from a hydrogen tank to be introduced into the nozzle therethrough;
• a ring-shaped inner wall provided so as to define a bore configured to eject hydrogen;
• a ring-shaped outer wall spaced apart from the ring-shaped inner wall in an outward direction, the ring-shaped outer wall being provided so as to define a hydrogen flow path configured to allow the hydrogen introduced through the hydrogen introduction portion to flow therealong;
• a ring-shaped front end wall provided so as to connect front ends of the ring-shaped inner wall and the ring-shaped outer wall to each other, the front end wall being configured to block a front end of the hydrogen flow path;
• and
• a ring-shaped rear end wall extending from a rear end of the ring-shaped outer wall to the front end of the ring-shaped inner wall, the rear end wall being provided such that a hydrogen ejection port is defined between the rear end wall and the ring-shaped inner wall, and wherein
• a thickness of at least one of the ring-shaped inner wall and the ring-shaped outer wall is gradually increased with increasing distance from the hydrogen introduction portion such that a sectional area of the hydrogen flow path is gradually reduced with increasing distance from the hydrogen introduction portion, and
• wherein the venturi tube is provided at the inlet thereof with a plurality of recirculated hydrogen introduction holes configured to allow the recirculated hydrogen to be introduced into the venturi tube therethrough.