Engine, rotary device, power generator, power generation system, and methods of making and using the same

A rotary device, comprising:

• a) a first central axle or shaft;
• b) an inlet configured to receive at least one fluid;
• c) a first rotary disc comprising two plates or discs having a continuous space therebetween from an opening of the inlet to a circumference of the rotary disc, the two plates or discs being (i) sealed to each other at the circumferences of the two plates or discs and (ii) spaced apart at a first distance adjacent to the central axle or shaft and at a second distance at the circumference of the two plates or discs, the second distance being smaller than the first distance, wherein the inlet is in continuous fluid communication with the space between said two plates or discs, the first rotary disc is configured to rotate around the first central axle or shaft, and said first rotary disc has a plurality of nozzles at a distal edge thereof, said nozzles being oriented to expel the fluid in a predetermined direction;
• and
• d) a wheel or cylinder having a plurality of buckets or cups on an inner or outer circumference thereof, configured to receive the fluid expelled from the nozzles.