| With the dramatically increase of global energy consumption,the development andapplication of novel energy-saving technologies have become an important demand for modern society.Organic Rankine Cycle?ORC?is the most effective method to convert low-grade waste heat into high-grade electricity.As a heat and power conversion equipment,the performance of ORC system is greatly influenced by its the expander.However,most of the expanders are not so competitive due their disadvantages of low efficiency,serious leakage and short life.To overcome these problems of current expander,a radial inflow turbogenerator based on aerostatic bearing was designed.Based on this expander,a 50 k W ORC system was established for the purpose of power generation from low-temperature waste heat.The relevant experiments were conducted and analyzed.The main results and conclusions are as follows:?1?Thermal and structural analysis were carried out on the radial inflow turbogenerator,the structure dimension and performance parameters for the turbine were obtained at the given working conditions.Solidworks software was adopted to design 3-Dimensional volute,static cascade,rotor blades and the diffuser.The radial inflow turbogenerator was finally fabricated.?2?With carbon dioxide as the working fluid,the performance testing research of radial inflow turbogenerator was tested in experimental platform.Experimental results showed that the maximum rotational speed of the turbine was up to 26000r·min-1,the highest temperature drop was up to 63.6°C,the maximum output power was 20.47 k W,the maximum isentropic efficiency was 80.6%and the maximum electromechanical efficiency was 91.1%.?3?Based on the experimental study of 3 k W small ORC low temperature waste heat power generation system,the performance of 50 k W ORC system were analyzed and optimized by using Aspen Plus software.The effects of working conditions on the thermal efficiency,exergy efficiency and irreversibility of the ORC system were systematically investigated.The optimum working conditions and operation parameters for this 50k W ORC system was determined.The performance of basic ORC system and ORC system with regenerator were analyzed,it was concluded that thermal efficiency and exergy efficiency of ORC system with regenerator was higher than that of the basic ORC system,increased by 1.37%and 4.44%,respectively.?4?A pilot 50k W ORC low temperature waste heat power generation experiment platform was built with R245fa as the working fluid.Saturated water vapor?150°C?and circulating cooling water?10°C?were selected to be the heat source and cold source,respectively.The influence of operation parameters on evaporator output state was analyzed emphatically according to system control requirements.The experiment results show that the flow rater of working fluid had greater influence on the evaporator than that of heat source and cooling water.The output temperature and pressure of evaporator is decreased with the rise of working fluid and cooling water flow rate,and it is also increased with the rise of heat source flow rate.When the outlet state of evaporator fluctuates,it is easy to mainly adjust the flow rate of working fluid and take the flow rate of heat source and cooling water as a secondary role to restore the evaporator outlet state. |
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