Experimental research on double-hole steam condensation effects and models under different diameters and pitch to diameter ratios conditions

•The de, and P/de mutual influences on the double-hole DCC effects are analyzed.•The penetration lengths are affected by the adjacent plumes specific interactions.•Double-hole steam DCC analytical models are revised with feature parameters.•The double-hole DCC HTCs are calculated in the range of 0.4-2.8MW/m2°C. The multi-hole steam Direct Contact Condensation (DCC) is of high efficiency in mass and heat transfer, which has been widely used in the engineering application, especially the advanced nuclear reactor power plant passive safety system. Most of the researches concerned on the single-hole steam DCC characteristics, whereas the multi-hole steam DCC heat transfer effects are influenced by a variety of mutual factors, and the micro mechanisms and models of which are still not very clear yet. In the present work, the double-hole steam condensation effects and models under different spraying diameters and pitch to diameter ratios (P/de) conditions are investigated based on the scaled IRWST & ADS experimental facility. The key parameters including the steam plumes, temperature distributions, penetration length, and heat transfer coefficients, etc. are analyzed. The experimental results show that both the P/de and de can impact the overall condensation behavior and the corresponding penetration length with variation range from -40% to 60% compared to the single-hole condensation cases, further influencing the double-hole steam DCC heat transfer effects. The revised double-hole steam condensation analytical models are proposed to depict the key condensation characteristics. Based on theoretical model and experimental results, the HTC calculation methods are developed to quantitatively estimate the double-hole condensation effects in the range of approximate 0.4-2.8MW/m2°C, which is in similar magnitude with the single-hole theoretical model. However, in overall, the double-hole HTC values are lower than the single-hole cases under the specific mutual influences between the adjacent plumes including overlapping, coalescences, and possible deflection with angles. The present theoretical and experimental work provide important references for the engineering multi-hole spargers design and modification.