In order to improve the film cooling efficiency of the turbine blades, triangular crater holes and V-shaped crater holes were designed based on cylindrical holes, and the influence of different crater depths was discussed. Pressure sensitive paint technology was used to measure the adiabatic film cooling efficiency under different blowing ratios M. Results show that the film cooling performance of the crater holes is superior to that of the cylindrical hole at all blowing ratios. Increasing crater depth is beneficial for triangular crater holes to improve film cooling efficiency. The film cooling efficiency of V-shaped crater holes increases with the increase of crater depth at M=0.5 and 1.0, but the film cooling efficiency first increases and then decreases at M=1.5. At the same crater depth, the downstream film cooling performance of V-shaped crater holes is better than that of triangular crater holes, but the opposite is true when the crater depth is D and M=1.5.

A numerical simulation method was used to study the influence of small inlet distortion intensity caused by radial intake on the aerodynamic performance of axial flow compressor. Results show that the radial intake mode can cause a maximum total pressure distortion intensity of 1.50% at the inlet of the axial flow compressor, and reduce the stall margin and peak efficiency of the axial flow compressor by 1.64% and 0.66% respectively. During the rotor throttling process, the total pressure distortion intensity at the inlet becomes smaller, but the influence on the aerodynamic performance of the axial flow compressor becomes greater. The small inlet distortion caused by radial intake makes the inflow velocity in the blade tip region decrease, which weakens the influence of the inflow on the blade tip leakage flow, so that the tip leakage vortex spirally breaks in advance during the rotor throttling process, resulting in the deterioration of flow capacity in the tip region, and the flow loss in the tip region increases, thus reducing the aerodynamic performance of the rotor.

Based on the domestic process simulation software Simtech Simulator, the equilibrium model, the kinetic model and the reduced-order model of the entrained-flow gasifier were integrated to form a set of professional model of the entrained-flow gasifier, and the modeling and validation of the actual industrial gasifier were carried out. Results show that the established gasifier professional models can predict the gasification results of air production (AP) coal-water slurry fluid-bed gasifier well, among which the kinetic model and the reduced-order model have higher prediction accuracy, and the absolute prediction error is less than 0.5%, indicating that the established models have good prediction ability. At the same time, the models can also be used to study the influence of gasification temperature and kinetic parameters on the gasification results, and carry out the gasifier flow field analysis, which provides a new way for the optimization of the gasification process.

In response to the difficulties in effectively extracting fault characteristics from acoustic emission (AE) signals of the hydraulic turbines, as well as the problems of imprecise and time-consuming fault classification in signal spectrum during the training process, a method for hydraulic turbine cavitation state recognition based on broad convolutional neural network (BCNN) was established. The linear mapping feature layers of broad learning system(BLS) were replaced by the convolutional layers and pooling layers of convolutional neural network (CNN), the obtained CNN feature nodes were used as inputs for the enhancement layers. By training the network parameters, a BCNN model was built. The BCNN model was used to classify, train and test AE signals from the hydraulic turbine cavitation under different working conditions. Results show that the established BCNN model can accurately and quickly classify and recognize four different cavitation states of the hydraulic turbines, achieving average recognition accuracy rate of 99.37%, with average time consumption of 44.16 s.

The drying process of a type of high burn-up spent fuel dry storage container for domestic third generation nuclear power units was analyzed theoretically and studied experimentally. Results show that, it is suitable to use the adsorption drying process for treatment, and the drying process needs to last at least 4.1 h, which can meet the drying standard that the water vapor content in the container is lower than 400 Pa as required in the equipment specification book. The drying process is divided into two stages. In the first stage, there is a large amount of liquid residual water in the container, and the humidity is relatively stable. In the second stage, there is only water vapor, and the humidity drops rapidly. More than 5/6 of the moisture in the container is discharged through the cooler in test bench, and the remaining is absorbed by the dryer.

In order to obtain the influence of confinement shape on thermoacoustic instability in swirling premixed combustion chamber, researches were conducted on the combustion oscillation mechanism, three-dimensional flame structure and flow field characteristics by numerical simulation for the combustion with different confinement shapes. Results show that, by changing the equivalence ratio at the combustion chamber inlet, the thermoacoustic instability is significantly suppressed in slope confinement compared with that in dump confinement. The flame dynamic structure in dump confinement shows periodic changes, while the flame dynamic structure in slope confinement is basically unchanged. With the increase of slope angle, the area of corner recirculation zone decreases, and the thermoacoustic instability is significantly improved. The main reason is that the vortex shedding process of corner recirculation zone in slope confinement is limited, while the intensity and frequency of vortex generation and shedding, and the contact degree between vortex and flame are both decreased, which leads to a decrease in the interaction between vortex and flame, including the physical processes such as the stretching and twisting of vortex on the flame, and the heating of vortex by flame. This weakened interaction reduces the unstable disturbance source in combustion chamber, which is conducive to suppress the thermoacoustic instability. The application of slope confinement may have a potential to become a passive control method to effectively suppress the thermoacoustic instability in a wide operating range.

Boiler combustion monitoring is of great significance to the safe operation of boilers and has long been a focus of research. The sound generated by combustion can directly reflect its state changes. However, due to factors such as high temperature, dust, and high-frequency noise, it is extremely difficult to effectively extract the sound characteristics inside the boiler. In response to this, a combustion feature extraction method based on one-dimensional convolutional neural network and voiceprint technology was proposed. Based on the construction of a combustion sound acquisition experimental platform, the sound characteristics corresponding to various combustion and non-combustion states were extracted. By calculating the Gini index of each feature of the voiceprint, the best features of the flame voiceprint were selected. The robustness and accuracy of the flame voiceprint model were verified by comparing the noisy and noise-free dataset models. The results show that in the original data, the sound feature training accuracy can reach 97.13%, and the training accuracy after optimization is increased to 98.26%; in the dataset with added noise, the optimized feature training accuracy can reach 93.29%.

In order to improve the flow separation and aerodynamic performance of wind turbine airfoil, an auxiliary device installed on the suction surface of airfoil was proposed. Taking NACA0021 as the main airfoil, the computational fluid dynamics (CFD) method was used to compare and analyze the aerodynamic performance of the original airfoil and the main airfoil with auxiliary device in the range of attack angle of 0°-24°. Results show that the asymmetric auxiliary winglet S809 has a significant effect on increasing lift and reducing drag of the main airfoil. It can effectively suppress the generation of large-scale separation vortex on the suction surface of the main airfoil at some angles of attack, reduce the stall area, make the flow separation point move backward, and delay the flow separation. In addition, the S809 auxiliary winglet increases the pressure coefficient of the main airfoil suction surface and the overall pressure difference, and significantly improves the aerodynamic performance of the main airfoil.

To investigate the effect of the wind turbine blade airfoil with cracked trailing edge on aerodynamic performance and static structure, the effects of the height and depth of trailing edge cracking on aerodynamic parameters and internal flow of the S809 airfoil were analyzed, and the changes in airfoil equivalent stress and vibration characteristics were examined. Results show that before the airfoil stalls, the aerodynamic performance of the airfoil with cracked trailing edge is much lower than that of the original one, and the cracked height has a significant impact on the aerodynamic performance while the cracked depth has little effect. However, the impact of cracked depth on the static structure of the airfoil is more notable than the cracked height. The increase in cracked height alters the aerodynamic shape of the trailing edge, thereby leading to a significant reduction in the aerodynamic performance of the airfoil before the stall but a slight increment after the stall. The trailing edge thickness increases with increasing cracked depth, resulting in a slight improvement of the aerodynamic performance compared with the airfoil with smaller cracked depth. After the trailing edge cracks, the equivalent stress of the trailing edge increases and the risk of resonance in the natural frequency range is promoted.

In order to improve the problems of flow separation and low efficiency of vertical axis wind turbines (VAWT), an active shunt baffle (ASB) structure was proposed. Based on the NACA0021 airfoil, the instantaneous torque, wind energy utilization coefficient, average tangential force and pressure field of vertical axis wind turbine blades under the action of shunt baffle were numerically analyzed by computational hydrodynamic method. Results show that the shunt baffle structure can effectively weaken the flow separation phenomenon caused by the large angle of attack of the blade in the windward area, increase the torque of the blade, and improve the wind energy utilization coefficient of the vertical axis wind turbine in the range of low blade tip speed ratio to different degrees. When the baffle is located 0.50c from the leading edge of the blade (c is the chord length of the blade), the length is 0.15c and the extension height is 0.04c, the maximum wind energy utilization coefficient of the vertical axis wind turbine of the active shunt baffle can reach 0.46, which is 9.5% higher than that of the original vertical axis wind turbine.

In order to study the dynamic characteristics of the compressed air energy storage (CAES) system in the energy storage stage and the energy release stage, the dynamic simulation models of the CAES system in the energy storage stage and the energy release stage were established based on the MATLAB/Simulink platform, and the gas storage tank and water storage tank, which were important components in the system, were simulated. The temperature and pressure of the system changing with time were obtained. Then, according to the transfer function of each module, a primary frequency modulation simulation model was established, and the frequency response of the system was analyzed by adding 10%, 8% and 6% step load disturbances and 10%, 8% and 6% continuous load disturbances to the system. Results show that under the step load disturbances, the larger the disturbance in the primary frequency modulation stage, the faster the system frequency recovery. Under continuous load disturbances, overshoot will occur, and the overshoot will increase with the increase of disturbance.

Flywheel energy storage (FES) is a promising solution for improving frequency regulation performance and operational stability of thermal power units. To enhance the comprehensive performance of FES in participating in secondary frequency regulation, based on an improved whale optimization algorithm (WOA) with variational mode decomposition(VMD), a coordinated control strategy for flywheel-assisted secondary frequency regulation of thermal power units was proposed. Firstly, based on control mechanisms on the machine side and grid side of the FES unit, a control system model of the FES array tailored to 1 000 MW ultra-supercritical thermal power units was established, as well as a secondary frequency regulation model for the collaborative control of the FES system and the ultra-supercritical units. Furthermore, an improved VMD method based on the WOA was proposed, achieving the optimal allocation of responses to AGC instructions for thermal power units and FES systems. Moreover, a control strategy for improving the charge and discharge margin of the SOC of the flywheel system was designed based on distribution results, and a flywhek-assisted secondary frequency regulation control strategy for thermal power that comprehensively considered the frequency regulation performance and the reliability of the flywheel was developed. Results show that the proposed control strategy can increase the AGC performance evaluation indicator of the unit by 16.72%, while reducing the SOC of FES and the main steam pressure fluctuation in thermal power units.

Comprehensively considering factors such as tooth surface friction and time-varying meshing stiffness, a nonlinear dynamic model of bending-torsion coupling for planetary gear systems was established. The influence of the root crack fault of the planetary gear on system dynamic characteristics under two conditions of internal and external meshing was studied, and a planetary gearbox experimental rig was established to verify the system model. The results show that under the two conditions of internal and external meshing, there are significant differences in the amplitudes of the fault characteristic frequency, its harmonic frequency, and side frequency components around the meshing frequencies in the system response spectrum diagram. Compared with external meshing, the system time-domain response shock is more obvious under internal meshing, and the phase trajectory diagram shows a diffusion phenomenon. Considering the time-varying effect of transmission path, the modulation frequency due to the planetary carrier rotation occurs in the system response spectrum, which is consistent with the frequency structure of the experimental rig vibration signal. That verifies the validity of the established model.

To address the issue of non-linear correlation between SCADA data of wind turbine units, a feature crossover mechanism was introduced and improved, and used for monitoring status of wind turbine gearboxes. Firstly, a two-stage cross feature selection method was proposed, which comprehensively considered the causality, correlation and data distribution differences among variables to screen features with strong hidden associations and low redundancy for cross-selection. Secondly, the factorization machine was improved by crossing only the benchmark variables within the cross feature group with the remaining variables, significantly shortened the generation time while generating reasonable cross features. Finally, the improved feature crossover algorithm was applied to the condition monitoring task of gearboxes in a certain wind farm. The results show that the proposed method, combined with five models, can achieve excellent effects and significantly improve the models' monitoring performance.

The carbon content of fly ash is one of the important parameters to realize the online measurement of boiler efficiency, but the current measurement device for fly ash carbon content has the disadvantages of a long measurement period and a high failure rate. To solve this problem, a novel improved adaptive least squares support vector machine (IALSSVM) algorithm with improved model update method was proposed, and this algorithm was used to establish a dynamic soft measurement model of fly ash carbon content for a 660 MW coal-fired boiler, in which important variables were selected by Pearson correlation analysis, while the information of important variables was fused by kernel principal component analysis (KPCA) method. Simulation results show that, the average absolute prediction error (MAE) and mean absolute percentage error (MAPE) of the soft measurement model on the test set are 0.171% and 19.814%, respectively, and the goodness of fit (R²) is 0.843, which has a high level of accuracy and stability. In addition, compared with the traditional method, the calculation speed of the novel model update method can be improved by about 30%, which plays an important role in promoting the online application of the model and realizing boiler closed-loop combustion optimization.

Based on the application background of spray evaporation technology in desulfurization wastewater treatment, comparisons were conducted on the advantages, disadvantages, and adaptability of different existing spray evaporation technologies applied in operational units with concentration reduction and solidification for wastewater. Common research methods for single droplet evaporation were summarized, and the design and operating conditions of various single droplet evaporation apparatuses were introduced. After which, the droplet drying process and commonly used kinetic models were elaborated, while influencing factors on the evaporation of desulfurization wastewater droplets, such as water quality and process parameters, were analyzed. Finally, the application of numerical simulation technologies related to spray evaporation of desulfurization wastewater was summarized, and research prospects were specifically proposed. Relevant summarized contents can provide a reference for the application of desulfurization wastewater zero-emission technology and the design of apparatus based on spray evaporation.

In order to enhance the flexibility of biomass power plants, the technology of existing biomass power plants coupled with energy storage was investigated, and a novel energy storage system coupling biomass power generation with heat pump energy storage was proposed. A model and relevant evaluation indexes were established, and the influence of key parameters on system performance was analyzed. Results indicate that the system with better performance can be obtained by improving the effectiveness of heat exchangers, and improving the isentropic efficiencies of compressors and expanders. Taking a biomass power plant with the rated power of 12 MW, main steam temperature of 540 ℃, and feedwater temperature of 220 ℃ as a research example, for the established biomass-heat pump energy storage system with the isentropic efficiencies of compressor and expander of 0.88, ambient temperature of 30 ℃, external heat exchanger effectiveness of 0.984 6, and regenerator effectiveness of 0.975 0, the coefficient of performance (COP) of system and the cycle efficiency can achieve 1.423 and 50.09%, respectively. This study can provide a theoretical basis for the technological transition of biomass power plants to energy storage operation.

In the process of burning hazardous waste in a rotary kiln, an image-based rotary kiln flame combustion stability prediction model was proposed to address the problems of relying on manual observation and lack of real-time performance in traditional combustion diagnostic methods. By building a pilot experimental platform, the CCD camera was used to obtain real-time images of flame combustion in the rotary kiln, and six flame feature quantities were extracted from these flame images, including average gray scale, effective flame area, high temperature area of flame, high temperature area rate of flame, centroid offset distance and circularity, and then a flame combustion stability prediction model was established based on the principal component analysis and support vector machine. Finally, the effectiveness of the model was verified by field experiments. Results show that the model can monitor and predict the combustion state of rotary kiln in real time and provide decision support for operators, and shows good prediction accuracy and practicability in practical application.

To coordinate the reliability and comprehensive performance of the combined cooling, heating and power system, a hot standby redundancy strategy was proposed based on the full redundancy strategy. Meantime, a flexible operation mode of the system was designed for this strategy, and the number configuration of operation and standby equipments was optimized. Taking commercial buildings in five representative cities as the research objects, optimization models were established to evaluate the reliability, economy, energy efficiency and environmental performance of the systems under different redundancy strategies, and compared with the non-redundant systems. Results show that the economic indicators of the non-redundant systems are significantly reduced due to equipment failures, which is the main reason for the integrated performance decline. Under the full redundancy strategy, the system availability is as high as 99.61%, but the integrated performance is the worst. Under the hot standby redundancy strategy, there is a competitive relationship between reliability and integrated performance. The system reliability of Beijing area is the highest, but the integrated performance is only 8.43%, while the system reliability of Kunming area is the lowest, but the integrated performance is as high as 25.63%.

Aiming at the problems such as slow convergence speed and easy falling into local optimal solution of existing intelligent algorithms in solving the problem of multi-objective optimal scheduling of virtual power plant, an optimal scheduling model of virtual power plant containing carbon capture was established with maximum income and minimum carbon emission as the objective functions, and the multi-objective sand cat swarm optimization(MOSCSO) was used to optimize the proposed model. The optimization results were compared with the multi-objective grey wolf optimization and multi-objective genetic optimization. The entropy weight-TOPSIS multi-objective decision method was used to screen the schemes optimized by MOSCSO, and the comprehensive optimal scheme with both economic and environmental protection was obtained. Results show that the scheme obtained by the MOSCSO is superior to the other two optimizations. The total system income of the comprehensive optimal scheme is 602 600 yuan, and the carbon emission is 249.15 t. Compared with the scheme that only considers the maximum system income, although the system income of this scheme is reduced by 8.90%, the carbon emission is reduced by 41.95%.

Heat storage in central heating networks has significant potential in reducing the energy supply costs of combined heat and power (CHP) units and improving renewable energy consumption. However, the system faces challenges in effective operation and dispatch optimization due to the coupling of heat and electricity and uncertainties in energy supply and demand. An energy dispatch optimization model considering heat-electricity semi-decoupling was developed on a system coupling CHP units with wind and solar power. A deep deterministic policy gradient (DDPG)-based dispatch optimization method based on Markov decision processes was designed to address the issues of heat-electricity coupling and uncertainties in energy supply and demand during system operation. The real-time energy flow dispatch of the units was optimized by training neural networks to adapt to randomly changing energy supply and demand scenarios. Dispatching simulations were carried out for three typical load scenarios: high, regular, and low load. Results show that the DDPG-based heat-electricity semi-decoupling dispatch method can effectively adjust unit output, meeting both electricity and heat demands, while ensuring the safety and sustainability of the heating network. Compared with rule-based algorithms, the DDPG algorithm shows superiority in reducing overall dispatch costs and effectively utilizing wind and solar energy. In the three load scenarios, the DDPG algorithm reduces overall dispatch costs by 2.46%, 7.49%, and 10.55%, respectively, and decreases curtailment rates of wind and solar power by 1.98, 3.40, and 4.86 percentage points, respectively.

The latent and sensible heat in the exhaust of the existing gas-fired hot water boiler, which accounts for about 10% of the lower heating value of the fuel input, remains underutilized. In response to this, an experimental platform to recover waste heat from gas-fired boiler flue gas was built and the impact of electro-compression heat pumps recovering flue gas condensation heat on boiler system efficiency and economy was analyzed. Additionally, an operation optimization strategy for the coupled gas-electricity system was proposed. Results show that the higher the return water temperature and heat load of the boiler, the higher the exhaust gas temperature of the boiler body, and the lower the thermal efficiency. As the boiler proper's thermal load and return water temperature increase, the heat pump integration improves more significantly the coupled system's thermal efficiency, with an increase of 4.4-10.4 percentage points. Raising the boiler load and lowering the return water temperature can enhance the heat pump's coefficient of performance (COP), shortening the payback period of the heat pump system to within three years. Since the heat pump's optimal real-time power shifts toward lower power consumption and higher efficiency with increasing electricity prices, the heat pump output should be adjusted in real-time based on boiler load and gas-to-electricity price ratio.