Research On Performance Of Free Piston Expansion Hydraulic Power Takeoff System

At present,there are a large number of waste heat and pressure resources in my country’s industrial field,which have not been fully utilized due to the lack of effective technical means.Therefore,the development of a new type of industrial waste heat and pressure energy recovery system is important for improving my country’s energy utilization efficiency and promoting the realization of "carbon Peak","carbon neutral" goals are of great significance.The free piston has the characteristics of variable expansion ratio,small volume and low friction loss,which has caused extensive research on it by scholars from all over the world,but so far there is still no suitable and commercialized free piston expander system for mass production.Recycle lowgrade waste heat and pressure resources.This research group has developed a free-piston expansion hydraulic power output system,which can convert the thermodynamic energy of the working fluid into hydraulic energy,and transmit the energy to various parts of the factory through hydraulic pipelines for output and work,improving energy utilization efficiency while reducing production.cost.In this paper,an exploratory study on the operating performance of the system is carried out from the perspectives of principle analysis,simulation research and experimental research.Based on AMEsim software,the simulation model of the free-piston expanding hydraulic power output system was built,and the simulation study of the influence of single factor on the system performance was carried out.The research results show that: when the system runs stably,the pressure in the working chamber of the expander,the speed and acceleration of the piston,and the output power of the hydraulic load all show periodic and regular changes,and the design of the counterweight mechanism can make the gas expansion process of the system never complete.The expansion is raised to overexpansion,increasing the net cycle work produced during a single duty cycle of the system.With the increase of counterweight mass,intake pressure loss,piston speed and load instantaneous output power gradually decrease,and the net cycle work,piston stroke and system average output power and efficiency of the system all show a trend of first increasing and then decreasing.;With the increase of intake pressure and intake duration,the operating performance indicators of the system show a gradually increasing trend.Based on the orthogonal experiment to study the influence of multiple factors on the system performance,the range analysis method and variance analysis method were used to study the effect and significance level of different operating parameters on the operating performance of the free-piston expanding hydraulic power take-off system.The results show that the primary and secondary effects of operating parameters on system performance are:intake pressure > intake duration > counterweight mass,and intake pressure and intake duration have extremely significant effects.At the same time,an experimental platform for a free-piston expansion hydraulic power output system was built and verified by experiments.The results show that the overall change trend of the simulation results and the experimental results is consistent,and the error accuracy between the experiment and the simulation is controlled within 10%,which basically verifies the accuracy of the free-piston expanding hydraulic power output system simulation and the orthogonal experiment scheme.