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  • Research & Analysis
    Experimental Research on Flow Resistance Characteristics of Supercritical Water in a Rod Bundle
    Wu Gang
    2022, 36(4): 223-228. https://doi.org/10.19806/j.cnki.fbsb.2022.04.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An experiment was carried out to study the flow resistance characteristics of supercritical water in a fuel assembly simulator of supercritical water-cooled reactor. The experimental parameters covered the pressure of 23-25 MPa, mass flux of 350-700 kg/(m2·s) and heat flux density of 200-600 kW/m2. The variation laws of friction pressure drop and friction resistance coefficient of supercritical water were obtained. The results show that under the given conditions of pressure, mass flux and heat flux density,with the increase of fluid temperature, the friction resistance coefficient first increases and then decreases, and there is a peak before the pseudo-critical temperature,showing a Λ-shaped distribution. The friction resistance coefficient decreases obviously with the increase of mass flux, but it is insensitive to the changes of pressure and heat flux density. The variation of the thermophysical properties has a great impact on the friction resistance coefficient, and the friction resistance coefficient empirical correlations based on constant-property fluid is difficult to accurately predict the flow resistance characteristics of supercritical water in the 2×2 rod bundle.
  • Research & Analysis
    Numerical Study on Heat Transfer Characteristic of Integrated Receiver-Storage Units
    Luo Xianfeng, Yang Song, Wang Jun, Hong Jie
    2022, 36(4): 229-234. https://doi.org/10.19806/j.cnki.fbsb.2022.04.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the FLUENT software, heat storage process of 8 h and heat release process of 16 h for the integrated receiver-storage units were numerically simulated, the temperature distribution of rock and air in the packed bed was obtained, its heat transfer characteristics were studied, and the influencing factors of thermal performance were analyzed. The results show that during the heat storage process, the axial and radial temperature distribution of the packed bed are not uniform. Thermo-cline appears along the axial direction, and a local high temperature area appears along the radial direction on the upper part of the packed bed. The axial and radial temperature distribution over time is influenced by the existence of the return pipe. At the equilibrium point, the rock temperature equals to the air temperature. The efficiency for 8 h heat storage process of the integrated receiver-storage unit is 97.6%.The position in height of the return pipe outlet from the ground does not affect the thermal efficiency. The pressure difference of the circulating fan mainly affects the heat release efficiency and solar-to-heat efficiency. The average diameter of the rock particles mainly affects the absorption efficiency and heat release efficiency.
  • Research & Analysis
    Research on Water Erosion of Last Stage Long Blades in Low Pressure Cylinder of Steam Turbine
    Yang Jiandao
    2022, 36(4): 235-240,248. https://doi.org/10.19806/j.cnki.fbsb.2022.04.003
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    Taking the last stage long blades in the low pressure cylinder of a steam turbine as a research object, combined with the numerical calculation method and the particle transport model, researched were conducted on the braking force and braking loss of the last stage long blades under different working conditions, while the aerodynamic pressure and water hammer pressure of each blade height section were given. Results show that the worst region influenced by the water erosion is the top part of the last stage blade, and the more severe water erosion would occur in the last stage long blades under small volume flow condition.
  • Research & Analysis
    Simulation Calculation and Verification of Critical Speed for High Speed Industrial Steam Turbine
    Bian Jichao, Gao Qian, Qin Huiyu, Kong Chuimao
    2022, 36(4): 241-244. https://doi.org/10.19806/j.cnki.fbsb.2022.04.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For the determined rotor, SolidWorks software was used for simulation. The results show that compared with the simulation results and high-speed dynamic balance test results, the critical speed of the measuring points of the front and rear bearings of the steam turbine rotor is within the allowable error range of 5%. The vibration variation trend of the measuring points of the front and rear bearings of the steam turbine is basically consistent with the results of the high-speed dynamic balance test, which verifies the accuracy of the simulation method and lays a foundation for the rapid development of the rotor of the high-speed industrial steam turbine.
  • Research & Analysis
    Handhole Cover Leakage Analysis for Water Wall Header of Waste Incinerator
    Li Xianshuang, Gao Chenglong, Cheng Yi, Liu Xinxing
    2022, 36(4): 245-248. https://doi.org/10.19806/j.cnki.fbsb.2022.04.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The leakage reasons of the water wall header handhole cover of waste incinerator in a power plant were analyzed by means of macroscopic inspection, geometric dimension measurement, chemical composition analysis, mechanical property detection, metallographic analysis, scanning electron microscopy and energy spectrum analysis, etc. The results show that overheating operation exists in the water wall header, high temperature sulfur corrosion occurs on the outer surface of the cover, and erosion corrosion occurs on the windward side of the cover. The joint action of high temperature and corrosion leads to the serious thinning of the wall thickness of the cover, and cracking and leakage occur under the pressure of the inner wall working medium.
    • Nuclear Technology
  • Nuclear Technology
    Application on Seismic Fragility Analysis of Steam Generator in a Nuclear Power Plant Based on CDFM Method
    Zhang Kefeng, Ma Yuanrui, Liang Xingyun
    2022, 36(4): 249-252. https://doi.org/10.19806/j.cnki.fbsb.2022.04.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on conservative deterministic failure margin (CDFM) method, an introduction was given to the process and result of the seismic fragility analysis of the steam generator in a nuclear power plant, while disscussions were conducted on the engineering application of CDFM method and the calculation of each margin factor and high confidence of low probability of failure (HCLPF) value. Results show that by adopting CDFM method, the HCLPF value of the steam generator can satisfy the design requirements, which also has a margin.
  • Nuclear Technology
    Feasibility Research on the Start-up with Non-nuclear Steam of a Sodium-cooled Fast Reactor Turbine
    Yao Yao, Yu Yan, Wu Fangjie
    2022, 36(4): 253-256. https://doi.org/10.19806/j.cnki.fbsb.2022.04.007
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    To analyze the feasibility of the start-up with non-nuclear steam of sodium-cooled fast reactor turbine under a certain boundary condition, based on the simplified model of the thermal system of the sodium-cooled fast reactor, a thermal balance calculation was established for the start-up with non-nuclear steam, and corresponding optimized schemes were proposed. Results show that, with only using steam generated by the heat storage of the primary and secondary loop of the reactor, the steam flow can not meet the requirements of the start-up with non-nuclear steam, while the start-up with non-nuclear steam of sodium-cooled fast reactor turbine is feasible when combined with auxiliary steam.
    • Design & Manufacture
  • Design & Manufacture
    CFD Research on the Performance of a New Type Sliding Vane Expander
    Jiang Yunhui, Chen Yaping, Wu Jiafeng, Gu Huaduo
    2022, 36(4): 257-262. https://doi.org/10.19806/j.cnki.fbsb.2022.04.008
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    A new type sliding vane expander was proposed, in which the air cylinder rotating with the rotor can effectively reduce the wear and friction in the cylinder, the working volume can be increased by reducing the rotor, and the flow condition can be improved by adding guide vanes. In order to explore the influence of rotor structure on the performance of expander, the RNG k-ε turbulence model was selected and four schemes with different rotor sizes were simulated by FLUENT software and dynamic grid technology, and the characteristics of internal flow field, as well as the change rules of exhaust flow, temperature and leakage flow were obtained. The results show that the minimum clearance ratio increases from 0.03 to 0.06, the continuity and stability of exhaust are enhanced, the average exhaust flow is increased by 80.66%, the average exhaust temperature is decreased by 11.21 K, the average leakage is decreased by 2.13%, and the isentropic efficiency is increased by 5.08 percentage points.
  • Design & Manufacture
    On-site Remanufacturing of Sealing Surface of Reheat Safety Valve Seat in an Ultra Supercritical Unit
    Lu Jian, Tang Bin, Zhu Leiyuan, Lu Zhilong, Ma Yaoqing
    2022, 36(4): 263-265,276. https://doi.org/10.19806/j.cnki.fbsb.2022.04.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The defects of Stellite cemented carbide on the sealing surface of X11Cr1MoWVNb9-1-1 steel based safety valve seat sealing surface, such as spalling, cracking and blow damage, were solved by on-site remanufacturing the reheat safety valve seat sealing surface of a 1 000 MW ultra supercritical coal-fired power generation unit, to ensure the safety of the unit. It has been proved by practice that through the application of reliable cooperative welding and heat treatment process, the remanufacturing of Stellite cemented carbide on the sealing surface of valve seat can be completed with high quality at the unit maintenance site.
    • Automatic Control
  • Automatic Control
    Optimization of AGC Coordination Control System in a Thermal Power Unit
    Zhuang Wei, Kang Lei, Sun Anna, Tian Yu, Zhao Tailei, Yuan Yindong
    2022, 36(4): 266-271. https://doi.org/10.19806/j.cnki.fbsb.2022.04.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To meet the requirements of indexes of automatic generation control (AGC) regulation performance for the power grid, corresponding optimization measurements were proposed for the comprehensive evaluation index of AGC regulation performance, while the control strategies and parameters of the coordination control system and key subsystems were optimized. Results show that, by adopting the optimized scheme, the comprehensive evaluation index of AGC regulation performance can be significantly increased, and the fluctuation range of key parameters of the unit also can be significantly improved.
  • Automatic Control
    Differences in Combustor Protection of Siemens PCS Combustor under Different Fuels
    Wang Yongzhe
    2022, 36(4): 272-276. https://doi.org/10.19806/j.cnki.fbsb.2022.04.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The combustor protection logic differences of Siemens platform combustion system (PCS) combustor under gas turbine gas mode and fuel mode were compared, and the operating characteristics under different fuels were analyzed. The results show that due to the difference of fuel properties, the difference of relevant protection logic set points is small, indicating that Siemens PCS combustor has good fuel adaptability and high operation flexibility.
    • Operation & Retrofit
  • Operation & Retrofit
    Effects of Sludge Mixed Combustion on the Performance of Wall Type Tangentially-fired Boiler
    Yang Kun, Ding Shifa, Zhang Tao
    2022, 36(4): 277-281,296. https://doi.org/10.19806/j.cnki.fbsb.2022.04.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to understand the influence of sludge mixed combustion on the actual operation of the boiler, a control test was carried out on a 660 MW wall type tangentially-fired boiler. Sludge was mixed combustion under high, medium and low load, and compared with the working condition without sludge. The results show that when the sludge with water content of 72% under the condition of 2% blending ratio, the temperature distribution of boiler furnace is roughly the same, the average temperature decreases by about 15 K, the smoke exhaust temperature of the unit increases slightly, the emission concentration of NOx and SO2 decreases, the emission concentration of CO increases, the coking of mixed fuel ash residue increases slightly, and the boiler efficiency decreases by about 0.2%. Combined with the heavy metal detection and dioxin emission test results of mixed fuel ash residue, it is concluded that it is feasible for coal-fired units to burn low proportion and high water content sludge under various loads.
  • Operation & Retrofit
    Research on Combustion Optimization Technology of a 660 MW Four-wall Tangentially Fired Boiler
    Duan Hongbo, Cheng Hong, Cheng Zhihai, Zhao Qingdong, Wu Tao, Zhu Yao
    2022, 36(4): 282-286. https://doi.org/10.19806/j.cnki.fbsb.2022.04.013
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A 660 MW ultra-supercritical boiler adopts four-wall tangential combustion arrangement, which has long-term problems in the operation process, such as large temperature fluctuation of water cooling wall under low load, and frequent overtemperature of rear screen superheater under high load. Combined with numerical simulation analysis and field test research, it is found that the main reasons of large combustion deviation and heating surface overtemperature are the output deviation of burner caused by burner layout, complex heat load characteristics of burner area and unreasonable air distribution mode. A combination of precise air distribution technology, the control optimization of primary air volume of coal mill and the automatic control optimization technology of secondary air baffle is proposed to solve the problem of boiler heating surface overtemperature.
  • Operation & Retrofit
    Analysis on Retrofit for Combined Utilization of Residual Pressure and Waste Heat of a 600 MW Pure Condensing to Heating Air Cooling Unit
    Liu Qiusheng, Yuan Zhenliang, An Jiangtao, Zhou Mingjun, Li Yongliang, Li Qiong
    2022, 36(4): 287-292. https://doi.org/10.19806/j.cnki.fbsb.2022.04.014
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a 600 MW air cooling unit from pure condensing to heating as the research object, the combined utilization of residual pressure and waste heat was proposed through using the steam ejector and the low-pressure steam turbine, and analyses were conducted on this unit for energy saving. The heating period was divided into four stages, and the change of the heat consumption rate in different heating stages was analyzed. The changes of the steam injector recovery exhaust steam quantity and the low-pressure turbine power were calculated under different back pressures of the unit and circulating water flows of the heating network. Calculation results show that, with the operation mode of the 30 kPa back pressure of the unit and the maximum circulating water flow of the heating network, the optimal benefit of the unit can be obtained with the largest amount of waste steam, the highest power of low-pressure steam turbine, and the largest benefit of energy saving.
  • Operation & Retrofit
    Analysis and Treatment of the Tripping Process of a 660 MW Double Reheat Unit
    Chen Xin, Xu Jian, Cao Yang, Zhang Lanqing, Zhang Yaohua
    2022, 36(4): 293-296. https://doi.org/10.19806/j.cnki.fbsb.2022.04.015
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For a tripping accident in a 660 MW ultra-supercritical double reheat unit resulted from the over-temperature of exhaust steam of high-pressure cylinder during commissioning, analyses were conducted on the tripping reasons, while corresponding measures were proposed. Results show that the tripping of the unit is caused by the illogicality of the controller of exhaust steam temperature of high-pressure cylinder, the turbine cylinder cut-off and the bypass. By adopting the optimized logic, similar accidents can be avoided, and the safety and stability of the unit operation can be improved.