Modeling And Simulation Of Helium Turbine Closed-cycle Device

In order to improve the efficiency of10MW high temperature gas cooled reactor system,a helium turbine closed-cycle was used in HTR-10GT to replace the steam turbine cycle. Inthe helium turbine closed-cycle, the helium flow was heated by the fission heat created in thecore and turned to be mechanical energy in the helium turbine to drive the generator. Thehelium turbine closed-cycle device developed by China is the only one practicality heliumturbine in the world and the study on design and operation for the helium turbine closed-cycledevice is still in the stage of accumulated experience, so the simulation study on the heliumturbine closed-cycle device is necessary.This thesis focuses on the helium turbine closed-cycle device as the object. The lumpedparameter models of the helium turbine, the helium compressor, the precooler, the inter-cooler,the recuperator, the axis and the pipes have been established. In order to describe the nuclearfission heat produce, the core lumped parameter model employed the point reactor model withsix groups of delayed neutron and sovled by the fourth-order Runge-Kutta method. In the corelumped parameter model, the reactor was nodalized based on the thermal-hydraulic propertiesduring the heat transfer process; The recuperator lumped parameter model was establishedbased on its structure and operation principle and taken the influence caused by therecuperator configuration into the heat transfer coefficient and pressure loss coefficientcalculations; The helium compressor lumped parameter model was established based on theaverage cross-section method, considered the affection caused by the shape of the flowchannel to the total pressure loss coefficient and calculated the characteristics step by step;The helium turbine lumped parameter model employed the quasi-steady state method and thecurve fitting method to calculate; The precooler and the intercooler lumped parameter modelemployed the constant heat transfer coefficient and the pressure loss coefficient during thecalculation.The sub-simualtion programs were built by Fortran language, compiled and run underCompaq Visual Fortran6runtime environment, The simulation results has been comparedwith the design and operation parameters of HTR-10GT, so as to validate the accuracy andcorrectness of the program. The entire system simulations have been done, including thesteady-state simulation of the nominal operating conditions and the dynamic simulation of the start-up condition.The results show that the helium turbine closed-cycle device model and the simulationprogram can reflect the HTR-10GT normal conditions correctly as well as the dynamiccharacteristics of the variable conditions. The results can be used as the basis for theoptimization of the device and for further study of the control characteristics.