Modeling And Simulation Of Mobile Power Plant Thermodynamic System

Mobile power conversion device;Thermal system;The small nuclear power unit of simulation modeling can be transported by means of transportation to provide realistic and economically feasible energy security for remote areas or islands.It can also be used as a backup power source in various emergency situations to provide power to areas hit by natural disasters;It has a good application prospect.This paper used APROS platform to establish the simulation model of mobile nuclear power conversion device to study the stability and reliability of the operation of the device,and studied the impact of evaporator rupture,condenser vacuum failure and circulating cooling water valve blockage on the system.Based on the basic heat exchange unit of APROS thermal edition,the dc evaporator simulation model of nuclear power conversion device was constructed,and the accuracy of the simulation using the six-equation calculation model was verified by B&W’s DC evaporator experimental data.The characteristics of dc evaporator are studied from the aspects of heat transfer and flow.The results show that the calculation curves of convective heat transfer coefficient in single-phase and two-phase zones have the same heat transfer characteristics as the test curves.The results obtained in the working section of the evaporator are consistent with the experimental data,which lays a foundation for the complete model construction of the secondary circuit.The models of steam turbine,feedwater heating,cold end and auxiliary system were compared and verified under different loads.The errors of simulation and design data reached the design requirements.On the basis of steady state to complete nuclear power simulation system,variable load and dynamic simulation test,according to the simulation results,the main parameters and design parameters of different load system error less than 3%,in the process of load change all the parameters meet the design requirements,the change trend of each parameters in the dynamic test and theoretical analysis,the simulation model has higher simulation accuracy.A rupture model of dc evaporator is established.Through studying the centralized and distributed rupture models,it is shown that the distributed rupture model can reflect the experimental parameter changes more accurately.On this basis,the influence of the rupture position and size of the heat exchange tube of the dc evaporator on the system is studied.The results show that as the leakage rate of the break increases or the position of the break gradually approaches the secondary outlet,the steam flow rate and temperature at the outlet of the evaporator gradually decrease and the humidity increases,which is easy to cause water erosion of the steam turbine,and at the same time,the primary side flow rate decreases and the core cooling is insufficient.The model of condenser leakage fault is established,the accuracy of the model is verified by experimental data,and the influence of non-condensing gas accumulation on condenser vacuum and unit output is simulated.Based on the established valve sticking fault model,the influence of the valve sticking on the control quality of the system is studied.The results show that with the increase of the valve sticking degree,the response time of the valve is prolonged,the fluctuation amplitude of the system parameters is larger,the period is longer,and the control quality and stability are gradually reduced.