船用蒸汽蓄热器放汽过程动态特性数值模拟

  目的  船用蒸汽蓄能器可为船舶大型汽力装置提供推力，为保障其安全稳定运行，有必要研究其在大负荷释能扰动条件下的热力不平衡特性。  方法  根据船用蒸汽蓄能器的特点，建立热力非平衡释能模型。通过对比仿真数据与实验数据，验证热力非平衡释能模型的准确性。采用数值模拟分析大负荷释能扰动下船用蒸汽蓄能器的热力非平衡特性，揭示非平衡分数、非平衡压差和非平衡温差等关键表征参数的分布规律。  结果  计算结果表明，在蒸汽蓄能器的释能过程中，由于水介质的导热系数低，水温传导变化速率滞后于压力响应速率，所以蓄能器内会发生自发闪蒸现象，导致蓄能器的释能流量、压力及温度表现出强烈的热力非平衡状态。  结论  研究成果可为实船蒸汽蓄能器释能过程的优化设计提供数据参考。

Numerical simulation of dynamic characteristics of the discharging process for a marine steam accumulator

  Objectives   Marine steam accumulator can provide impetus for large steam power equipment of ships, it is necessary to study the thermodynamic non-equilibrium characteristics under the condition of large energy release disturbance in order to guarantee its safety and stable operation.  Methods   A model of large energy release disturbance considering thermodynamic non-equilibrium is established according to the characteristics of the marine steam accumulator. The accuracy of the thermodynamic non-equilibrium energy release model is verified by comparing the simulation data with the experimental data. The thermodynamic non-equilibrium characteristics of marine steam accumulator with large discharge disturbance are studied. The key parameters of non-equilibrium fraction, non-equilibrium pressure difference and non-equilibrium temperature difference characterizing the thermodynamic non-equilibrium process is revealed by numerical simulation.  Results   The calculation results show that the change of water temperature is behind the pressure response because of thermal inertia of water space during the process of energy discharge marine steam accumulator. This made that the spontaneous flash evaporation happen in the accumulator. The mass flow, pressure and temperature of steam accumulator energy discharge showed a strong thermodynamic non-equilibrium state.  Conclusions  These research results can provide data reference for the optimization design of the actual marine steam accumulator.