The establishment of system dynamic simulation model of supercritical carbon dioxide(S-CO_2)compression test system is of great significance to system design

system performance prediction and control strategy establishment. Consider time lag effect of the cooler and the pipe

a component-level thermodynamic model of the cooler

compressor and orifice plate is firstly established

and a dynamic simulation model is built up by combining the enthalpy equation of the system. The static and dynamic accuracy of the model is validated. On this basis

the dynamic response characteristics of a 350 kW S-CO_2 compression test system to the orifice plate opening disturbance are studied. The results show that

during the increase process of the orifice opening

the inlet temperature of the compressor almost unchanges

the pressure ratio decreases

the efficiency and output power of the compressor increases at first and then decreases. When the orifice opening is constant

the compressor efficiency increases slightly and the output power almost has no change. When the orifice opening increases linearly

the loop flow rate and compressor inlet temperature have the maximum adjustment

and both of them have a linear relationship with the opening change rate. Besides

adding 300 L tank in front of the compressor will offset the system stability parameters and enhance the compressor's robustness to the throttle valve opening disturbance.