Influence of Motive Nozzle Supersonic Part Profiling on the Effectiveness of the Vaporization Process: Experimental Results

This article presents experimental results for motive nozzles with profiled supersonic parts of parabolic, hyperbolic, and elliptical shapes, compared to conical nozzles with unprofiled supersonic parts. This study examined the effect of nozzle geometry and profile on thermodynamic and flow parameters of the vaporization process. The measured parameters included outlet pressure, flow velocity, and mass vapor content, along with dimensionless efficiency indicators, such as relative outflow velocity and the velocity coefficient. Graphical dependencies of these parameters on the relative initial underheating, (1 − εs0), were obtained. This parameter represents the ratio of the pressure difference between inlet and saturation conditions (at inlet temperature) to the inlet pressure. The results show that profiled nozzles operate effectively over a wider range of (1 − εs0) = 0.20–0.45, compared to conical unprofiled nozzles. The vaporization constant for profiled nozzles remained at bn ≈ (2/3)0.5 along their length. The velocity coefficients for profiled designs were 4–6% higher, and the volumetric vapor content at the outlet was also greater, indicating a more efficient vaporization process. Overall, the findings demonstrate that profiling the supersonic section of a motive nozzle improves the operating range, flow characteristics, and vaporization quality compared to conventional conical designs.