The floating platform undergoes six degrees-of-freedom of motion in the marine environment, making the flow field around the blade fluctuate drastically, and the changing flow field will have a huge impact on the dynamic response of the blade. A two-way fluid-structure interaction simulation of the NREL 5 MW wind turbine was carried out using the CFD-CSD coupling method. Based on this, the UDF technique introduced the floating platform motion to study the blade deformation and the overall torque and thrust changes under the surge, pitch, and yaw motion. The results show that the three typical platform motions of the surge, pitch, and yaw make the blade deformation amplitude increase, and the increase of flapwise and torsional deformation is more significant than that of edgewise deformation; the surge motion has the greatest influence on the blade deformation and aerodynamic performance, the maximum change range of torsional deformation can reach 70%, the peak values of the torque and thrust are increased by 30.51% and 11.75% respectively; the pitch and yaw motions reduce the average torque and thrust.

The static corrosion behavior of 316L stainless steel and 347 stainless steel at 500 ℃ in Solar Salt (60%NaNO₃ + 40%KNO₃) was investigated via static corrosion test. Corrosion kinetic curves of 316L stainless steel and 347 stainless steel in molten salts at 500 ℃ were obtained through measuring the weight changes of the specimens at each time intervals. XRD and ICP-MS were employed to characterize the phase and component of molten nitrate salts; XRD, SEM/EDS were used to characterize the morphology, composition and microstructure of the corrosion products on the surface and the cross section of corroded specimens. Finally, combining the changes of molten salt and stainless steels, the corrosion mechanism of 316L stainless steel and 347 stainless steel in Solar Salt was discussed respectively. Results showed that the corrosion behavior of 347 SS in Solar Salt at 500 ℃ was characterized by mass gain. As time goes on, the trend of 316L stainless steel increased first and then decreased, while the trend of 347 stainless steel was on the increase. SEM/EDS showed that 347 stainless steel was more likely to be oxidized, while the chromium element in 347 was prone to dissolve, comparing to 316L stainless steel is better stability in Solar Salt, that is, 316L stainless steel is more corrosion resistant.

During the low load operation of coal-fired units, the SCR denitration catalyst may be deactivated by ammonium bisulfate (ABS). The experimental tests are carried out on this phenomenon and the results show that: 1) with the flue gas temperature below the ABS condensation temperature, the catalyst will be deactivated due to the gradual deposition of ABS in the micropores. The ABS condensation temperature is inversely proportional to the micropore diameter, and the ABS concentration is positively related to the product of NH₃ and SO₃ concentrations in the flue gas; 2) the micropores with pore diameters of 2~20 nm are still the main structure of wide temperature denitration catalyst as well as the conventional catalysts, which cannot change its fate of ABS deactivation under low load; 3) the physical reversibility of catalyst ABS deactivation makes “combination of prevention and treatment” still the fundamental method to solve the ABS problem.

A concentrated downcomer stub of a boiler drum with 13MnNiMoR steel in a power plant, which was replaced due to cracks and non-metallic inclusions after 14 years in service, was dissected, and the behavior characteristics and influence of the non-metallic inclusion were analyzed through chemical composition analysis, mechanical property testing, microstructure and defect morphology observation. The results show that under service load, non-metallic inclusions become crack sources and microcracks by means of self cracking, interface separation from matrix or hole formation at the end, and microcracks converge to form macro cracks. When tensile and impact tests on the serviced materials, the area without inclusions was cracked and expanded in plastic mode. While innon-metallic inclusions area, the cracks nucleated with non-metallic inclusions and expanded in a brittle mode, resulting in a significant reduction in the strength and plastic toughness of the materials compared with that before service.

A new combined cooling, heating and power system is proposed based on solar photovoltaic, wind power, ground-source heat pump and energy storage unit (WSSH-CCHP) to improve the efficient utilization of renewable energy resources and the entire system energy efficiency. The comprehensive evaluation indexes are developed by using the analytic hierarchy process to account for the system performance of energy efficiency, economy and environment. The mixed integer linear programming (MILP) algorithm is employed to perform the optimization on the selection of equipment types, capacity allocation and system operation stratagem. A case study on an energy center in Jinan city is conducted to explore the optimal performance and operation characteristics of WSSH-CCHP. The obtained results indicate that the proposed system comprehensive performance is much better than the separate production system, which provide useful information for the development of CCHP system with wind-solar-storage and heat pump and the study on its integrated optimization and operation characteristics.

The traditional waste heat valve control technology is mainly divided into two methods, mechanism modeling and data-driven. However, in practical applications, the former is difficult to accurately describe due to the complex mechanism. The latter requires high data quality and full working condition samples, which is difficult to meet in a short time. Aiming at the above problems, a fusion-driven optimization method for waste heat valve control is proposed. Firstly, the mechanism knowledge and data knowledge are fused to construct a knowledge graph model based on fuzzy sets, and the valve opening knowledge is materialized. Secondly, the LSTM valve opening optimization model based on time protection mechanism is established, and the time protection mechanism algorithm is proposed to determine the optimal adjustment frequency of the valve. Finally, the recommended valve opening is obtained by knowledge reasoning. Through experimental analysis and verification, this method integrates qualitative knowledge such as waste heat recovery mechanism and quantitative knowledge such as equipment operation data. While improving the safety of equipment, the probability of generating high-temperature saturated steam enthalpy is increased by 94%, and the average daily increase is 8 640 kJ, which realizes the intelligent decision of waste heat recovery valve opening.

The Shockley-Queisser (SQ) limit sets an upper limit on the efficiency of conventional semiconductor photovoltaic devices. A thermophotovoltaic system (consisting of a heat source, a spectrally selective emitter and low bandgap photovoltaic cell) can work as an alternative to break this theoretical efficiency limit. To further improve the power generation efficiency of thermophotovoltaic (TPV) systems, an emitter with a multilayer cross structure based on metamaterials was designed in this work. Through optimization of its geometric size, the emitter demonstrates an excellent narrow-band emission spectrum. This effectively reduces the loss of low-energy photons below the bandgap of PV cells and avoids the absorption of high-energy photons that exacerbate lattice vibrations to cause thermal losses. Its application to TPV systems enables a perfect match with In_0.69Ga_0.31As cells with a bandgap of 0.6 eV. Detailed theoretical calculations of this TPV system show that the power generation efficiency can exceed the Shockley-Queisser (SQ) limit (41%) at 1 117 ℃, and will be further improved as the emitter temperature increases. When the temperature reaches 2 000 K, the efficiency is as high as 46.75%. Additionally, the narrowband emitter shows good angular insensitivity in the range of 0~60 degrees.

The growing complexity observed in the structures of cast aluminum fittings has posed significant challenges to conventional non-destructive testing techniques, rendering them inadequate in fulfilling the requirements for swift on-site inspection of irregularly shaped cast aluminum fittings. Consequently, an ultrasonic testing method based on flexible phased array probes was proposed. Firstly, a dynamic focusing algorithm for flexible phased array ultrasonic probes was introduced, and the basic simulation theory of CIVA multi-technique software platform was analyzed. Then, the dynamic focusing algorithm used to achieve deflection and focusing of ultrasonic beam was verified by simulation with CIVA, and the parameters of the flexible phased array ultrasonic probes were optimized through simulation. Finally, the effectiveness and feasibility of the testing method were verified through the inspection of typical cast aluminum fittings. The results show that phased array ultrasonic testing technology based on flexible array probes can meet the requirements of outgoing quality control and on-site rapid inspection of cast aluminum fittings with irregular shape.

Taking the gas fuel control valve of gas turbine as the research object, based on the computational fluid dynamics method, the flow field distribution and flow change rule of the gas fuel control valve under the actual operating conditions are studied, and the flow characteristic curve of the valve is fitted. The results show that the mass flow of the control valve at the same opening has nothing to do with the change of the pressure behind the valve, and is in a blocked flow state when the pressure in front of the valve is 2.650 MPa and the pressure ratio behind the valve to that in front of the valve is 0.49~0.78; Under the same pressure ratio, the discharge coefficient is approximately linear with the opening, which is consistent with the actual requirements of the project; There is a linear correlation between the flow coefficient and throat area. By optimizing the valve core profile, the linear curve of throat area with opening is improved, and the linearity of the flow characteristic curve is improved.

The supercritical carbon dioxide (S-CO₂) cycle power generation technology has become an epoch-making and revolutionary frontier technology in the field of thermal power generation because of its own technical advantages. Due to the very harsh working environment, S-CO₂ is easy to cause corrosion problems of equipment materials. In order to ensure the safe and effective operation of S-CO₂ system, the range of working medium parameters and candidate materials of the system’s key equipment are introduced. The current research status of corrosion behavior of metal materials in S-CO₂ environment are then reviewed. The corrosion mechanism in S-CO₂ carbon environment is elaborated in detail. The influences of temperature, pressure, impurities, flow rate and material composition on S-CO₂ corrosion process are summarized. Meanwhile, the research progress of S-CO₂ corrosion prevention and control technology is introduced. Finally, the shortcomings of existing research and the main direction of future research wereare summarized, so as to provide scientific basis for the safe operation of S-CO₂ recycling system in China.