Driven by the “carbon peaking and carbon neutrality” goal, hydrogen blending and pure hydrogen combustion technology of gas turbines have received widespread attention. Producing “green hydrogen” from renewable energy and applying it for power generation is the development direction of the energy field in the future. However, the fluctuation of hydrogen source will inevitably cause the change of hydrogen blending ratio of hydrogen blended gas turbine fuel. Therefore, the dynamic response characteristics of the gas turbine are studied when the hydrogen blending ratio fluctuates. Taking an F-class heavy-duty gas turbine as the research object, a dynamic model is built by using the modular modeling method to analyze the response characteristics of key parameters of the unit and the safe operation of components when the hydrogen blending ratio fluctuates under different loads. The results show that when the hydrogen blending ratio fluctuates, the turbine inlet temperature (T₃) will fluctuate violently, and T₃ overtemperature will occur in the high load region, which will lead to the deterioration of the blade working environment and affect the safe operation of the unit. The larger the fluctuation of hydrogen blending ratio and the higher the power output, the more obvious T₃ overtemperature phenomenon. However, the fluctuation of hydrogen blending ratio has a relatively small impact on the compressor, and the compressor can still maintain a reasonable surge margin.

Supercritical carbon dioxide cycle has many advantages such as small turbine size, small compressor power consumption and high cycle efficiency. In order to explore the cycle configuration with the highest power generation efficiency after the power generation system of supercritical carbon dioxide cycle coupled gas turbine, four cycle layouts were proposed. The main parameters of the circulating system were optimized by genetic algorithm with the maximum circulating efficiency as the optimization objective. Among the four schemes, the gas turbine/two-turbine supercritical carbon dioxide combined cycle system has the highest cycle efficiency, which is 44.87%. And the dynamic system analysis of the scheme, with the bottom cycle input heat load as the disturbance variable, explore the dynamic response of the system after the step reduction from full load to 90% load, 80% load and 70% load respectively. The results show that the response time of parameters near the flue gas heat exchanger is faster and the response time is longer when the shadow of thermal inertia is farther away from the flue gas heat exchanger in the working medium flow. At the same position, the response time of pressure is slightly longer than that of temperature, and the drop range of parameters near the high-temperature turbine is greater than that of the low-temperature turbine.

With the transformation of the power system to low-carbon, the proportion of new energy installed capacity is increasing year by year, renewable energy power generation has the characteristics of intermittent, the main power generation period and peak power consumption period are misaligned, there is an imbalance between supply and demand, and the demand for flexibility in power balance is intensified, and long-term energy storage power stations have become a magic weapon to solve the problem. According to the development of long-term energy storage technology, the technical characteristics, advantages and current bottlenecks of pumped storage, compressed air, lithium-ion batteries, flow batteries, molten salt heat storage, and hydrogen energy are analyzed, and the typical application projects of the above energy storage technologies are analyzed. Then, the typical scenario applications of energy storage are analyzed from different sides of the power supply side, the power grid side and the user side, and the application comparison of seven energy storage technologies in multiple scenarios such as energy transfer, auxiliary services, black start, and smooth new energy output is expounded. The technical parameters, battery selection, system wiring, energy management and other issues of chemical energy storage demonstration project, heat storage demonstration project and mechanical energy storage demonstration project were summarized and analyzed, and finally the future energy storage power station technology was prospected.

To study the thermal hydraulic characteristics of the printed circuit heat exchanger with rhombic fin channels, variations in thermal hydraulic characteristics on the hot and cold sides were analyzed by numerical simulation, with cold side inlet temperature of 313.15~353.15 K and hot side inlet temperature of 553.15~593.15 K. The working medium on the cold side and the hot side were S-CO₂ and gaseous CO₂ respectively. The comprehensive performance was compared between NACA0030 airfoil fin channels and rhombic fin channels. The results show that when the inlet temperature of S-CO₂ increases by 40 K, the total heat transfer decreases by 23.91%, and the pressure drop of hot and cold increases by 29.95% and 11.14% respectively. When the temperature of gaseous CO₂ increases by 40 K, the total heat transfer increases by 16.40%, and the pressure drop of hot and cold increases by 9.42% and 7.43% respectively.The inlet temperature of S-CO₂ has more obvious influences on the thermal hydraulic characteristics. The printed circuit heat exchanger with rhombic fin channels has less flow resistance and better comprehensive performance. The results have a certain reference significance for the design of printed circuit heat exchangers with discontinuous channels.

The high-performance supercritical CO₂ heat exchanger is the key core equipment to realize the efficient and compact S-CO₂ Brayton cycle system. S-CO₂ has a low heat transfer coefficient in the smooth channel, and seeking high heat transfer performance and low-resistance heat transfer structure is the key to the development of efficient and compact heat exchangers. Five-axis EDM was used to fabricate the straightly ribbed tube, and the heat transfer behaviors of S-CO₂ in the four-headed straight rib tube was experimentally studied, the effect of flow parameters on the heat transfer characteristics of the straight rib tube was systematically analyzed, and the difference in the heat transfer performance between the straight rib tube and the smooth tube was quantitatively evaluated. The influence of structural parameters on the enhanced heat transfer and resistance characteristics was studied by numerical simulation method, and the optimal straight rib tube structure was obtained. The results show that increasing the pressure and mass flow rate can reduce the wall temperature, improve the convective heat transfer coefficient, and the average heat transfer capacity of straight rib tube is about 1.96 times that of smooth tube. Compared with smooth tubes, straight ribbed tubes can effectively delay the occurrence of heat transfer deterioration, the ability to delay the occurrence of heat transfer deterioration by using straightly-ribbed tubes is increased by 0.3~1.8 times. When the fixed rib width W=0.5 mm and the rib height H=2.5 mm, the PEC is the best, and the value of PEC is1.58. However, the fixed rib height is H=0.5 mm, ε=0.33, and PEC of the straightly-ribbed tube is the best, with the value of PEC is 1.22.

Self-recirculation casing treatment can significantly improve the aerodynamic performance of the supercritical carbon dioxide centrifugal impeller in small flow rate region, but the improvement is not obvious near the large flow rate region. Therefore, the coupling effect between the self-recirculation casing treatment and the key parameter of the impeller is considered, and the coupling optimization of the casing treatment geometry and the impeller blade sweep angle is carried out to achieve a comprehensive improvement of the impeller performance. After the coupling optimization, the efficiency of the impeller is increased by 3.51%, 2.60% and 4.43% respectively under the large flow rate condition, the design condition and the small flow rate condition. The mechanisms of the coupling optimization for stability and efficiency enhancements are as follows. Under the large flow rate condition, the flow incidence angle of impeller is improved, the subcritical zone inside the impeller is reduced, then the condensation is suppressed and the flow capacity of the impeller is improved. Under the design condition, the recirculation flow of casing treatment is increased, more low-energy fluid near the shroud tip is removed, and the flow field structure downstream of the impeller is improved. Under the small flow rate condition, the internal blockage of the impeller is effectively reduced, the flow stability of the impeller is enhanced, and the mixing loss caused by the recirculation flow is improved, so the impeller efficiency is improved.

During frequent long-term standby state of gas turbine generator unit, the surface of 08Al carbon steel of waste heat boiler economizer fin tube will have serious corrosion problems. In this paper, the macroscopic corrosion phenomenon and corrosion rate of 08Al carbon steel above the critical humidity were studied by the method of hanging piece and electrical resistance probe. The results show that the corrosion rate of 08Al carbon steel is the fastest in the first 5 days under the constant environment of 20 ℃ and relative humidity of 70%, and the corrosion depth reaches up to 0.85 μm, accounting for 47.7% of the total change in the whole process. However, the most obvious corrosion phenomenon, including the change of weight and the surface corrosion area, occurred from about the 19th to the 25th day. With the relative humidity gradually increasing from the critical humidity of 70% (ambient temperature 20 ℃), the corrosion evaluation indexes of 08Al carbon steel show a linear upward trend. Nitrogen filling maintenance strategy under long-term standby state was formulated, effectively alleviating the corrosion condition of economizer fin tube of waste heat boiler.

The non-minimum phase plants with unstable zeros exists widely in the process of power production. Because of the non-minimum phase characteristics, the control system should ensure internal stability while completing output tracking, and improve response speed while overcoming the undershoot. The general PID control cannot meet the requirements of engineering applications. An engineering control and tuning method for non-minimum phase plants is proposed in this paper. Firstly, a robust PID controller is designed to ensure the stability of the closed-loop control system and overcome the under shoot of the system. Secondly, design a second-order filter that includes system position error, velocity error, and acceleration error to improve the response speed and dynamic performance of the control system. This method is simple, easy to tune, easy to configure in DCS, and has strong robustness to model uncertainty, which is worth promoting in engineering.

The carbon dioxide (CO₂) Brayton cycle system is compact, efficient and flexible, and has a good application prospect in the third generation photothermal system and the fourth generation nuclear power system. The deterioration of CO₂ heat transfer affects the safe operation of the unit. In order to study the deterioration of CO₂ heat transfer in the vertical riser, a CO₂ heat transfer characteristic system is established for experimental research, and the CO₂ heat transfer characteristics under subcritical and supercritical conditions are compared. The influence of thermal parameters on the deterioration of CO₂ heat transfer is obtained, and the prediction correlation of CO₂ critical heat flux is established. The predicted value is in good agreement with the experimental value (error ±30%). It is found that the peak value of wall temperature is higher when CO₂ heat transfer deteriorates at subcritical pressure. Far away from the critical pressure and increasing the mass flow rate are conducive to restraining the occurrence of heat transfer deterioration.

For enhancing the film stiffness of supercritical CO₂ (S-CO₂) hydrodynamic dry gas seal and reducing the additional power consumption due to the installation of heater in the seal inlet line, a new structure of S-CO₂ hydrostatic-dynamic dry gas seal with the heating of the ring body at the back of the static ring is proposed. Based on the conjugate heat transfer model, the pressure and temperature distribution of dry gas seal were simulated utilizing commercial software Fluent. The steady-state performance and flow field distribution of S-CO₂ hydrodynamic seal, hydrostatic seal and hydrostatic-dynamic seal were compared and analyzed, and the flow and heat transfer characteristics and power consumption of S-CO₂ hydrostatic-dynamic dry gas seals under different heating modes and heat temperatures were discussed. The results show that the film stiffness of the hydrostatic-dynamic dry gas seal is improved more than doubled compared with the hydrodynamic dry gas seal, while the leakage rate increased significantly by 35% at the same time. The power consumption under ring heating mode is 44% lower than that under direct gas heating mode, leading to better operating economy. It provides a new idea for the structure design and auxiliary system improvement of compressor dry gas seal in S-CO₂ power generation system.