Dynamic Modelling And Simulation Of Micro HAT Cycle Based On Component Characteristics

Humid Air Turbine(HAT)cycle is one of the most important developments in advanced power cycles.This system adds a complex water circuit,aftercooler,humidifier and economizer based on the regenerative cycle based on the gas turbine,which inevitably has a significant impact on the dynamic characteristics,safety and response speed of the cycle while improving the efficiency of waste heat utilization.This paper presents an in-depth theoretical analysis and experimental study of the dynamic performance of the HAT cycle,which is of great importance to the operation,control development and fault prevention of the unit:(1)The dynamic models of unit components of HAT cycle are established on the Simulink platform using a modular approach,including the general unit component models of the compressor,combustion chamber and turbine.The new component models of HAT cycle are established,including humidifier,aftercooler,economizer and recuperator,etc.The inertia model includes the thermal inertia model of air channel and the rotor inertia model.Combined with the control and properties of gas models,the model of micro HAT cycle is established.(2)Based on the experimental data obtained from the existing 100 kW micro HAT cycle test rig,the developed models of unit component and system model are verified in steady state and dynamic.The maximum relative error between the calculated model and the experimental data was 2.63%for the humidifier,while the relative errors for other components are within 2%.Compared with the unit component model,the relative error between the calculated values and the experimental data of the outlet fluid temperature of the recuperator and the turbine in the system increased slightly,but the dynamic tracking was still good.(3)The dynamic characteristics of the new ceramic foam humidifier are analyzed based on whether the influence of packing thermal inertia was considered,and the results showed tHAT packing thermal inertia would increase outlet air response time of humidifier by 6 s and the outlet water temperature response time by 9 s.The inlet water temperature and water flow rate of the humidifier are given step perturbations respectively,and it is concluded tHAT the outlet air temperature is more sensitive to the disturbance of the inlet water temperature,and the response time of the outlet water temperature are about twice as long as tHAT of the outlet air temperature is about twice as long.When the inlet water temperature rises,by reducing its flow rate can reduce the response time of the outlet parameters.The effect of the introduction of the humidifier on the overall dynamic characteristics of the cycle is analyzed by comparing the thermal inertia of the humidifier with tHAT of the other heat transfer components,where the response time for the exit parameters of the recuperator is around 100 s,the response time of the aftercooler and the economizer was around 150 s,while the response time of the humidifier is within 10 s,so the effect of the introduction of the humidifier on the thermal inertia of the system is almost negligible.(4)The HAT cycle dynamic model was validated using experimental data to compare the performance and dynamic characteristics of the regenerative and HAT cycles during the rampdown process of the fuel.The results show tHAT the output power and efficiency of the HAT cycle during the process is consistently about 15%higher than tHAT of the regenerative cycle,and the drop in exhaust smoke temperature is about 35℃ lower.The former takes about 200 s to reach a new stability time,while the latter takes only about 60 s.