Research on the steam jet length with different nozzle structures

• A theoretical model is proposed for jet lengths of different structural nozzles.
• Experimental results verify the conclusion of theoretical model.
• Steam jet length of straight pipe nozzle is longer than that of orifice nozzle.
• A universal semi-empirical correlation for different nozzle structures is proposed.

The effect of nozzle structure on the steam jet lengths of submerged condensation in quiescent water is investigated theoretically and experimentally. Two typical nozzles are analyzed and tested. Theoretical analysis shows that nozzle structure has a great influence on the steam jet length but was paid little attention before. Then a theoretical model for steam jet length with different nozzle structures is proposed based on the expansion and compression wave theory. Theoretical model indicates that steam jet length is greatly affected by nozzle structure. The steam jet length of straight pipe nozzle is longer than that of orifice nozzle under the same pool water temperature and steam mass flux, and the steam jet length is inverse proportion to the maximum expansion ratio, approximately. Then the theoretical model is verified by the experimental results. Finally, a universal semi-empirical correlation considering the nozzle structure is proposed. The prediction length corresponds to the experimental data very well and the discrepancy is within ±25% for different nozzle structures for the steam mass flux 400–800 kg·m−2·s−1 and water temperature 10–70 °C.