2. Efficiency and output
2.1. Output limitations
When steam passes through a narrow orifice or nozzle, it acquires kinetic energy at the expense of heat (enthalpy). The expansion of steam beyond the nozzle causes some of the generated kinetic energy to be converted to frictional heat. The result is the retention of some enthalpy, but a loss in pressure and increase in entropy (loss in availability of energy).
2.1.1 Steam valve pressure drop
2.1.2 Swallowing capacity