Archive

  • Select all
    |
    Boiler Technology
  • Boiler Technology
    Study on Operating Parameters Affecting the Pulverizer Outlet Temperature of a Boiler with Oxygen-enriched Combustion
    ZHANG Zhiyu, YANG Yongping, ZHAI Rongrong, CHEN Weipeng, XIAO Zhuonan
    2020, 40(2): 89-95. https://doi.org/10.19805/j.cnki.jcspe.2020.02.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To find the variation law of pulverizer outlet temperature with the operating parameters of a 600 MW subcritical boiler with oxygen-enriched combustion, a simulation model was established, based on which, monofactor analysis was conducted by the method of process simulation on the disturbance of various factors, such as the oxygen content in dry gas, the air leakage coefficient, the primary flue gas circulating proportion in exhaust gas, and the flue gas preheating temperature, etc., while multi-factor coupling and significant study were carried out using orthogonal method. Results show that the exit temperature of coal mill decreases with the rise of oxygen content in dry gas, which increases with the rise of the primary flue gas circulating proportion in exhaust gas, the air leakage coefficient and the flue gas preheating temperature. The significant relationship of various factors is as follows:the primary flue gas circulating proportion in exhaust gas > oxygen content > air leakage coefficient > flue gas preheating temperature. Among all the factors, the influences of both the oxygen content in dry gas and the primary flue gas circulating proportion in exhaust gas are particularly significant, the influence of air leakage coefficient is significant, while the preheating temperature of flue gas has influence in a certain degree.
  • Boiler Technology
    Effects of Ash Deposition on Heat Transfer in the Furnace of a Zhundong Coal-fired Boiler
    LIU Zhongyi, JIN Jing, ZHANG Binbin, HOU Fengxiao, ZHU Yizhou, ZHENG Liangqian
    2020, 40(2): 96-103. https://doi.org/10.19805/j.cnki.jcspe.2020.02.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The effects of heating surface ash deposition on the following in-furnace heat transfer parameters of a 330 MW Zhundong coal-fired boiler were analyzed by means of experiments and numerical simulation combined with thermal calculation, such as the heat flux, thermal conductivity and thermal effective coefficient, etc., after which, a curve was fitted for the relationship of outlet gas temperature of screen-type superheater and thermal effective coefficient with the thickness of ash deposition. Results show that the thermal conductivity of ash increases with the rise of ash temperature. When the thickness of ash deposition exceeds 10 mm, the decreasing amplitude of ash heat flux reduces, with steady combustion in the furnace, stable outlet gas temperature, low thermal effective coefficient and constant boiler efficiency. When the thickness of ash deposition increases from 0 to 10 mm, the heat flux of the heating surface drops significantly, while the average temperature in the furnace rises, with an increased outlet gas temperature of the furnace by 16.5%, a decreased heat effective coefficient by 68%, and a reduced boiler efficiency by 2.26%. The fitted curve may serve as a reference for structural design improvement and soot blowing optimization of the boilers burning Zhundong coal.
  • Boiler Technology
    Mass Transfer Characteristics of Corrosion Products in the Steam-Water Circulation System of Supercritical Units
    WANG Chao, LI Hongyuan, HOU Tianqi, CHEN Can, JIANG Dongfang, XU Hong
    2020, 40(2): 104-109. https://doi.org/10.19805/j.cnki.jcspe.2020.02.003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To find the mass transfer characteristics of corrosion products in the steam-water circulation system of supercritical thermal power units, a dynamic model was set up to describe the mass changes of corrosion products using fluid network theory based on the topology of steam-water circulation systems. Meanwhile, the mass propagation law of the corrosion products was calculated and analyzed at different loads. Results show that the mass transfer dynamics of corrosion products in the steam-water circulation system are affected by both the local mass transfer properties of the equipment and the characteristics of the steam-water network. When the unit load changes, the deposition rate of particles changes suddenly due to the variation of diffusion mode; the non-deposited particles exhibit a systematic distribution behavior owing to the network effect, and the mass of particles is an important parameter in the evaluation of deposition rate.
  • Boiler Technology
    Numerical Simulation on the Combustion in a 600 MW Opposed Firing Boiler
    LI Daolin, WANG Wenhuan, PAN Weiguo
    2020, 40(2): 110-116. https://doi.org/10.19805/j.cnki.jcspe.2020.02.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To accurately quantify the main parameters (such as speed, temperature and NOx concentration) of the flue gas entering the denitration system, a research model was established for the whole system from the boiler furnace to the economizer outlet, and subsequently numerical simulations were conducted on a 600 MW subcritical opposed firing boiler, during which, the swirl burner and the furnace were simulated as a calculation domain, the heating surfaces in the region of superheater, reheater and economizer were processed by user defined function (UDF), and the velocity field, temperature field and NOx concentration of the boiler and the outlet flue gas parameters of the economizer were obtained. Results show that the outlet flue gas parameters of the economizer are unevenly distributed. The denitration efficiency could be significantly improved while the ammonia escape rate could be remarkably reduced when the outlet parameters of the economizer are taken as the design or optimization conditions for the SCR denitration system.
    • Steam Turbine and Gas Turbine
  • Steam Turbine and Gas Turbine
    Study on Vibration Characteristics of Shrouded Blades Based on Hamilton Principle and Harmonic Balance Method
    WANG Weitao, NAN Guofang
    2020, 40(2): 117-122. https://doi.org/10.19805/j.cnki.jcspe.2020.02.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A dynamic model was established for the straight blade with parallelogram shroud to study the influence of different parameters on the vibration characteristics of the blade, during which, the straight blade was simplified as a cantilever Euler-Bernoulli beam, the shroud was seemed as a mass concentration point fixing with the blade tip, and the contact force between shrouded blades was defined using a spring model. A dynamic equation of the system was deduced based on Hamilton principle, while an equivalent dynamic equation of the blade with shroud was obtained by translating the compressive stress and friction force between the shrouds into equivalent stiffness and equivalent damping using harmonic balance method. The dynamic response of the system was then acquired by solving above equations using Runge-Kutta numerical method to find out how the gap of tip, the rub coefficient and the contact angle influence the vibration characteristics and the nonlinear behaviors of the model proposed. Results show that the resonance amplitude increases with the rise of the shroud gap in a certain range, while the gap has nearly no effects on the rotating speed in case of resonance. The resonance amplitude and range reduce with the increase of rub coefficient. There exists an optimal contact angle, when best damping effectiveness could be obtained. The vibration of blade is relatively stable under friction conditions.
  • Steam Turbine and Gas Turbine
    Influence of Tip Bleeding on the Stability of a Transonic Compressor
    YAN Song, CHU Wuli
    2020, 40(2): 123-130. https://doi.org/10.19805/j.cnki.jcspe.2020.02.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking the NASA Rotor 37 as an object of study, the influence of tip bleeding on the stability of the rotor was numerically simulated. Results show that tip bleeding could help to improve the stability of the rotor. The mechanism of stability enhancement comes from the suction action of tip bleeding, which reduces the area of tip blockage, and therefore enhances the flow capability in the tip region. The bleed position and flow rate interactively affect the rotor stability. At the bleed flow rate of 0.5% and 1.0%, the stable working margin of rotor gradually reduces with the bleed position moving backward; at the bleed flow rate of 1.5%, with the bleed position moving backward, the stable working margin tends to increase first and then decrease. When the bleed position is fixed at 20% C, the stable working margin of rotor increases first and then decreases with the increase of bleed flow rate; and when the bleed position is respectively at 60%C and 100% C, as the bleed flow increases, the stable working margin of rotor gradually increases accordingly.
  • Steam Turbine and Gas Turbine
    Unsteady Action of Upstream Purge Flows on the Flow and Cooling Effectiveness Around Rotor Endwall
    LU Zefan, CHEN Liu, ZHANG Fasheng, BAN Yu, DAI Ren
    2020, 40(2): 131-137. https://doi.org/10.19805/j.cnki.jcspe.2020.02.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To study the unsteady characteristics of turbine disc cavity outflows, the flow field in high-pressure turbine stages under different coolant mass flow ratios (MFRs) was obtained by solving the unsteady RANS equations with the SST turbulence model. Results show that the purge flow mainly affects the area in downstream rotor cascade. The interference of the unsteady potential field caused by relative motion of rotor blade enhances the fluctuation of circumferential pressure at the exit of rim seal. Hot gas ingestion happenes at MFR=0.4%, when the purge gas and the main stream alternatively flow in the endwall region. When the MFR gets up to 1%, the gas ingestion is suppressed, and the adiabatic film cooling effectiveness at leading dege of the blade is about twice of that in the case of MFR=0.4%, but where the temperature fluctuation is aggravated. The relatively high fluctuation of adiabatic film cooling effectiveness mainly lies in the middle of the flow passage at MFR=0.4%, which is in the area near the blade surface at MFR=1%.
    • Monitoring and Measurement
  • Monitoring and Measurement
    Steam Turbine Condition Monitoring Based on Multivariate State Estimation Technique and Hyper-ellipsoid Analysis
    SONG Ying, ZHANG Zhonglei
    2020, 40(2): 138-144. https://doi.org/10.19805/j.cnki.jcspe.2020.02.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To accurately monitor the operation status of steam turbines, a detection method was proposed by combining the multivariate state estimation technique (MSET) with the hyper-ellipsoid analysis (HEA). Based on multi-dimensional operating data of a steam turbine, the condition monitoring model was established using MSET to acquire the residual matrix between the measured data and the prediction values, which was subsequently analyzed by HEA to judge its operation condition. Results show that the method proposed could help to effectively monitor the operation condition of relevant steam turbines and to find out any abnormal situation in early stages.
    • Environmental Protection Technology and Equipment
  • Environmental Protection Technology and Equipment
    Effects of Sulfur-containing Potassium Salts on Formation Characteristics of SO3 over V2O5-WO3/TiO2 Catalyst
    XIAO Haiping, DOU Chaozong, YUAN Zonghai, LI Jian, GE Jinlin, Lü Hongkun
    2020, 40(2): 145-151. https://doi.org/10.19805/j.cnki.jcspe.2020.02.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    V-based catalysts with sulfur-containing potassium salts (K2S2O7 and K2SO4) were prepared using wet impregnation method, so as to study the effects of the sulfur-containing potassium salts on the formation characteristics of SO3 over V2O5-WO3/TiO2 catalyst, and to characterize the catalysts by various analytic techniques. Results show that the presence of K2S2O7 and K2SO4 would significantly increase the SO3 formation rate, which achieves the maximumm at 410℃ for the SCR catalyst with 3.6% K2S2O7. At the SO2 concentration of 3 000 mg/m3, the SCR catalyst with 3.6% K2S2O7 would generate the largest concentration of SO3. For catalysts with sulfur-containing potassium salts, the reduction property and surface area reduce, while the content of surface chemical adsorption oxygen, the V5+ and the vibration peak strength of V5+=O bonds increase obviously, resulting in enhanced oxidation ability of the catalysts.
    • New Energy
  • New Energy
    Study on Aerodynamic Performance and Flow Mechanism of Fractal Blades Based on Fractal Geometry
    ZHANG Li, LIU Yuhang, LI Chun, DENG Yunhe, LUO Hong
    2020, 40(2): 152-160. https://doi.org/10.19805/j.cnki.jcspe.2020.02.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the aerodynamic performance and flow pattern of a wind turbine, a fractal trailing-plate blade with fractal grids on the trailing edge was proposed. Three-dimensional flow field calculations were performed on the original blade, non-grid trailing-plate blade and fractal trailing-plate blade to study the influence mechanism of the non-grid trailing-plate and fractal trailing-plate on the flow field and aerodynamic characteristics of the blade. Results show that the fractal trailing-plate helps to improve the flow field structure around the blade, reduce the turbulence intensity on and around the suction surface, and effectively delay the flow separation. Besides, the fractal trailing-plate blade delays the stall while increasing the maximum lift coefficient, when the drag coefficient is smaller than that of the non-grid trailing-plate blade. In the vicinity of the stall angle of attack, the coefficient of resistance of the fractal trailing-plate blade exhibits better aerodynamic performance than that of the non-gird trailing-plate blade.
    • System Engineering
  • System Engineering
    Multi-attribute Evaluation on Energy Efficiency of Integrated Control Strategies for Pollutants from Coal Burning Based on Hot Gas Filtration
    SI Tong, WANG Chunbo, LIU Ruiqi, REN Yujie, HU Jian
    2020, 40(2): 161-168. https://doi.org/10.19805/j.cnki.jcspe.2020.02.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To obey the increasingly stringent environmental regulations and to satisfy the energy-saving and consumption-reducing demand for coal-fired power plants, a new integrated control route was proposed and demonstrated for the pollutants from coal burning based on hot gas filtration. Meanwhile, a three-layer 15-factor comprehensive multi-attribute evaluation system was established to analyze the difference in energy efficiency between the new route and two existing typical ultra-low emission control routes, in which, the factor weight was determined by analytic hierarchy process. Moreover, a fuzzy comprehensive evaluation was conducted from the aspects of environmental protection, technical efficiency, economical efficiency and social benefits of the new route. Results show that the new control route has higher overall energy efficiency, with higher economical efficiency and social benefits under the premise satisfying the ultra-low emission requirements. Simultaneously, the evaluation results reveal the relationship between an indicator and its main influence factors. This may serve as a reference for selection and optimization of similar control routes.
    • Nuclear Technology
  • Nuclear Technology
    Pressure Pulsation Behavior of a Reactor Coolant Pump with Mixed-flow Diffuser and Spherical Casing
    LAI Xide, YE Daoxing, CHEN Xiaoming, LIAO Qi
    2020, 40(2): 169-176. https://doi.org/10.19805/j.cnki.jcspe.2020.02.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To find the factors influencing the pressure pulsation behavior of a reactor coolant pump (RCP) with spherical casing, and to seek the relationship between the pressure pulsation and operating conditions, the time-domain and frequency-domain characteristics of pressure pulsation were carefully analyzed at different locations in the RCP under 5 typical operating conditions, based on 3D numerical simulation on unsteady flow through the full passage of the RCP. Results show that the pressure pulsation is mainly caused by the rotor-stator interaction (RSI) between the impeller and guide vane, and the main features of pressure pulsation depend on the geometrical parameters of the impeller, guide vane and spherical casing. The primary frequency of pressure pulsation is that of the impeller, and its maximum amplitude mainly depends on the operating flow, which reaches the minimum in the design operating condition. The amplitude of pressure pulsation in the impeller increases from the inlet to the outlet, which reaches the maximum at the impeller outlet, and then decreases from the inlet to the outlet of guide vanes. The unsteady flow in flow passage would cause highly irregular pressure pulsation under small discharge conditions. The pressure pulsation differs in the same circumference near impeller inlet, which is more intensive on the suction side than the pressure side of a blade, but is almost the same at impeller outlet under different operating conditions. The amplitude of pressure pulsation increases in the medium and high frequency area with the rise of operating discharges, due to the vortex and backflow formed in the spherical casing, which would increase distinctly when the RCP is operating at extreme small discharges. The spherical casing does have influence on the pressure pulsation in the impeller and guide vane, and the effect is stronger under smaller discharge conditions, but weaker under design and larger discharge conditions.