Affiliation:
1. School of Aerospace Engineering, VNU-University of Engineering and Technology, Vietnam National University, Hanoi, 144 Xuanthuy, Caugiay, Hanoi 100000, Vietnam
Abstract
Abstract
The flashing flow in a Moby_Dick converging-diverging nozzle under pressurized hot water from 460.5 to 483.5 K is simulated using a homogeneous compressible water-vapor two-phase flow model. The kinematic and thermodynamic mass transfer are accessed using the cavitation model based on the Hertz–Knudsen–Langmuir equation. Our simplified thermodynamic model is coupled with the governing equations to capture the phase-change heat transfer. This numerical method proved its reliability through a comparison with available experimental data of flow parameters inside the nozzle. Consequently, the present numerical method shows good potential for simulating the flashing flow under pressurized hot water conditions. The satisfying prediction of averaged flow parameters with a slight improvement compared to reference numerical data is reproduced. The results confirm a noticeable impact of the thermodynamic effect on the mechanism of flashing flow, resulting in a considerable decrease in the flow temperature and the saturated vapor pressure. The flashing nonequilibrium is significantly decreased, forcing the flashing flow to be classified as the usual cavitation behavior and better suited to homogeneous model. While the temperature drop is highly dependent on evaporation, the thermodynamic suppression is influenced by the condensation. The suppression effect, unobserved in water at a lower temperature in previous studies, is noticeable for the pressurized hot water flow characterized by the cavitation mechanism. The vapor void fraction decreased considerably in the radial and axial directions as the water temperature rose to 483.5 K in this study.
Funder
National Foundation for Science and Technology Development
Cited by
3 articles.
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1. A novel ELSA model for flash evaporation;International Journal of Multiphase Flow;2024-04
2. Cavitation Flows Past a Rotating Circular Cylinder;Journal of Fluids Engineering;2023-07-28
3. Numerical Simulation of Hot Water Flashing Flow in a Converging - Diverging Nozzle;The AUN/SEED-Net Joint Regional Conference in Transportation, Energy, and Mechanical Manufacturing Engineering;2022