Direct contact condensation of two-phase ammonia in the co-current subcooled liquid flow at the low mass fluxes
The paper presents a brief sensitivity study of direct contact condensation in the co-current flow of subcooled anhydrous ammonia. Two nozzles with inner diameters of 1.4 mm and 2.5 mm were tested under various conditions, including saturation pressures ranging from 11.7 to 23.1 bar, vapour qualitie...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-10-01
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| Series: | Case Studies in Thermal Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214157X25011827 |
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| Summary: | The paper presents a brief sensitivity study of direct contact condensation in the co-current flow of subcooled anhydrous ammonia. Two nozzles with inner diameters of 1.4 mm and 2.5 mm were tested under various conditions, including saturation pressures ranging from 11.7 to 23.1 bar, vapour qualities from 0.2 to 1.0, and vapour mass fluxes between 450 and 1300 kg m−2s−1. The condensation process was visually examined in a transparent tube with an inner diameter of 7.5 mm. The observed condensation front enabled the determination of average plume length under different boundary conditions and the estimation of conservative condensation heat transfer coefficients. The results indicate that existing models and correlations—primarily developed from steam-water experiments—fail to adequately predict ammonia condensation behaviour, both qualitatively and quantitatively. This comparison highlights the need for a robust phenomenological theory of the direct contact condensation mechanism. The study identifies the vapour Reynolds number as the primary factor influencing ammonia condensation intensity. A new phenomenological correlation is proposed, adequately capturing the experimental data within a ±30 % margin. |
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| ISSN: | 2214-157X |