Experiment And Simulation Study On The Non-equilibrium Thermodynamics Process Of Marine Steam Accumulator

The marine steam accumulator is applied to the aircraft carrier’s steam catapult due to its superior performance.The marine steam accumulator is an energy storage device which is used to provide the aircraft with the required steam.The application of steam accumulator will alleviate the disturbance of boiler which caused by the launch of the aircraft,and provide favorable conditions for the stability of the system.Because the steam accumulator is stored with steam and water two phase medium,there will be flash evaporation,condensation,a variety of complex process of heat and mass transfer during the very short timeframe.Thus the thermal hydraulic characteristics of marine steam accumulator will change acutely.Therefore the research that studying the mechanism and the variation trend of the working medium parameters is essential to protect the safety of the launch.Based on the non-equilibrium thermodynamic,the mathematical model was established which is suitable for different mode steam supply.With the help of some arithmetic modules of the Simulink and the invoking function,the mathematical model was transformed into simulation model after collating and analyzing the established mathematical model.The experiments of charging,discharging,continuous charging and discharging were carried out by the experiment platform of the marine steam accumulator in order to explore the change mechanism of the working medium parameters.The influence of metal heat storage on the working medium state parameter was studied through the combination of simulation and experiment,after the dynamic emulation model was verified by the experimental data.The working characteristics of the behind discharge mode were studied by simulation,at the same time the changing rule of the main parameters of steam accumulator was compared for the two kinds of steam supply modes.The influence of the different steam supply modes on the working medium state parameters was analyzed deeply.The results showed that during the experiment of charging(discharging),the pressure of steam accumulator was not stable at the value when the charging valve(discharging valve)was closed completely,but a phenomenon that the pressure dropped(rose)oppositely and then turned to stable is appeared.The pressure drop ratio caused by the uneven potential difference increased along with the decrease of the mass of storage water and the increase of the charging energy per unit time during the charge process.In the fast charge and discharge experiment,there will be temperature stratification for the water due to the metal heat storage,the influence of flash vaporization and condensation.The flow of charge steam,the initial pressure,the initial water level and the pressure difference of the charge process have a significant effect on the working medium parameters of the steam accumulator,so the operating parameters should be set reasonably in practice combining with the demand of launch.The metal heat storage will extend the charge and discharge time of steam accumulator,at the same time,it will also make the stable value of pressure lower for charge process and make the stable value of pressure higher for discharge process.If the steam accumulator is in the behind discharge mode,the energy was unequal between the charge steam and discharge steam,which made the water level of steam accumulator decrease In order to ensure the steam demand for the aircraft launch,the steam accumulator should be fed water timely.The research results lay a certain foundation for the follow-up study of marine steam accumulator,and will provide strong support for the system optimization and the selection of control scheme.