| With the rapid development of China’s economy,the demand for energy is increasing,and the effective use of energy has become an important issue in modern research.China has abundant waste heat resources of medium and low temperature,but the energy utilization rate is very low.The advantages of organic Rankine recycling system in recovering low temperature heat source have been paid much attention in China.The efficiency of expansion machine,the core component,directly determines the performance of organic Rankine recycling power generation.In this paper,an organic Rankine experiment system with industrial steam turbine as the prime mover is tested in the laboratory.After the test,the experimental system runs successfully,and the maximum output power can reach 0.9kw.The maximum no-load speed of the steam turbine is 2980r/min,which basically reaches the factory rated speed of the steam turbine.Meanwhile,the steam turbine efficiency increases with the rise of evaporation pressure,and the maximum efficiency of the steam turbine can reach 40.7% during the test.It is known from the performance test that the steam turbine efficiency performance has great room for improvement.Organic Rankine cycle power generation performance.Through ANSYS Workbench platform,the flow field numerical simulation study was carried out for the flow passage part of stator and stator blades of the experimental steam turbine.Affected by the blade profile,the static and moving blades showed that the pressure was uneven and there was a low pressure area.Vortexes appear at the roots of both stationary and moving blades due to fluid viscosity.Due to the influence of wheel hub,circulating working medium and blade profile,low-speed zones appear at the trailing edges of stationary blades and back of moving blades,resulting in obstructed aerodynamic acceleration of circulating working medium,stagnant flow and flow loss.The flow near the hub generates a large loss of viscous friction at the blade root,resulting in a large increase in entropy near the blade root and a large flow loss due to the turbulence and complexity of the air flow near the tip.The isentropic efficiency is 85.1%.In order to study the influence of different working medium on turbine efficiency performance,four working medium,R11,R123,R141 b and R245 fa,were selected.Under the conditions of different evaporation temperature and mass flow rate,through the calculation and analysis of runner flow and post-processing data,it was found that R11 had good performance,R123 followed by R245 fa.Select four leaf type geometry Angle as control variables,through the ANSYS Workbench platform,using the uniform design method to carry on the numerical simulation,and USES theuniflow solid coupling method to optimize the blade intensity,the results show that the optimized blade effectively improve the flow condition in the runner,pressure distribution more uniform,working medium flow more smoothly,vortex phenomenon obviously improved,the entropy increase or decrease in small,blade power capability,isentropic efficiency reached88.6%,increased by 3.5% before the optimization.The results of strength check show that the maximum deformation of the optimized blade is less than the tip clearance design,and the maximum equivalent stress is much less than the yield strength of the material.This paper has 48 figures,19 tables and 64 references. |
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