Laval nozzle is the critical part of supersonic separator to provide refrigeration environment. Due to the back pressure at the outlet of supersonic separator in dehydration process, the condensation characteristics of water vapor and the refrigeration performances of the nozzles are affected by the shock wave. Herein, mathematical models for the supersonic condensation and flow of the methane-water two-phase flow model were established, which were verified by the experimental data. The effects of different divergent angles on the refrigeration and condensation behavior in the Laval nozzle were studied considering shock wave. The results show that the refrigeration performance of the nozzle will be worsen under the presence of shock waves. With the divergent angle of the nozzle increased from 2° to 8°, the lowest temperature was decreased from 304.4 K to 291.8 K, the liquid mass fraction at the nozzle outlet was decreased from 0.84% to 0.133%, the maximum droplet radius that can be obtained was reduced from 2.54 × 10⁻⁷ m to 1.69 × 10⁻⁷ m due to the forward movements of the shock waves. The divergent angle of the nozzle is recommended to be designed to 4°–6° in consideration of the refrigeration performance.

拉瓦尔喷嘴是超声波分离器提供制冷环境的关键部分。由于超声波分离器出口在脱水过程中的背压，冲击波会影响水蒸气的凝结特性和喷嘴的制冷性能。本文建立了甲烷-水两相流模型的超声速凝结和渗流数​​学模型，并通过实验数据进行了验证。考虑冲击波，研究了不同发散角对拉伐喷嘴中制冷和冷凝行为的影响。结果表明，在存在冲击波的情况下，喷嘴的制冷性能将变差。随着喷嘴的发散角从2°增加到8°，最低温度从304降低。 由于冲击波的向前运动，⁻⁷  m至1.69×10 ^-7 m。考虑到制冷性能，建议将喷嘴的发散角设计为4°–6°。