Scramjet engines are mainstream power systems for hypersonic vehicles, and it has significant thermal protection demand and power supply demand during the long-time and high-Mach-number flight of hypersonic vehicle. An integrated cooling and power generation system based on supercritical CO₂ Brayton cycle is designed for a certain type of scramjet engine. The characterization model of wall heat source for this scramjet engine is constructed. The influences of key design parameters, such as heat absorption pressure, turbine inlet temperature, heat release pressure, and regeneration degree, on the system thermodynamic performance are investigated, as well as the coupling relationships among various design parameters. The optimal design schemes and performance of the integrated cooling and power generation system are obtained by the multi-parameter collaborative optimization. The thermodynamic advantages of the proposed system are also evaluated by comparing with the conventional system with a simple cycle as the baseline. The results show that the proposed integrated cooling and power generation system can achieve a maximum power generation efficiency of 15.9% and a continuous power supply of 206.2 kW, which exhibits a good potential for actual application. The smaller the pinch temperature difference during the heat absorption process of the engine wall, the more significant the thermal performance advantage of the proposed system compared to the benchmark scheme, and the maximum relative increase in power generation efficiency can reach 9.3%.

A novel healthy state monitoring method for offshore booster station platforms is proposed to enhance the damage detection capabilities under complex operating conditions. Using a deep learning framework based on memory unit autoencoders, the method magnifies fault-relevant features via denoising and angular domain resampling high-frequency vibration data from offshore boosting stations. The model employs a deep convolutional neural network to learn historical data patterns, constructs a hidden state memory bank, and achieves sparse matching between sample encoded features and the memory bank. Finally, a Gaussian mixture probability model is employed to model the generated membership scores to assess the health status of the booster station. A case study of the offshore booster station in Rudong, Jiangsu, validates the approach, achieving an anomaly recall rate and accuracy of over 98%, outperforming other comparison algorithms.

The RNG k-ɛ model was used to numerically simulate the flow and heat transfer characteristics of supercritical CH₄-H₂ mixtures in horizontal pipe. The thermal physical properties of the CH₄-H₂ mixtures with hydrogen ratio of 0~30%, as well as the heat transfer process of the CH₄-H₂ mixtures with hydrogen ratio of 0~15% in the horizontal tube were analyzed. The influences of mass flow rate (150~250 kg/(m²·s)) and heat flux density (150~250 kW/m²) on flow and heat transfer of the mixed working fluid with hydrogen ratio of 10% were studied. The results show that when the hydrogen ratio increases from 0 to 30%, the pseudo-critical temperature of the mixed working fluid increases slightly from 190.4 K and then sharply decreases to 181.7 K, and the pseudo-critical pressure increases from 4.3 MPa to 12.3 MPa. With the increase of the hydrogen ratio (0~15%), the heat transfer between the fluid and the wall is strengthened. The increase of mass flow rate strengthens the heat transfer capacity of the mixed working fluid and weakens the heat transfer deterioration caused by buoyancy effect. The increase of heat flux strengthens the heat transfer degree of the wall under the mixed working medium, and weakens the heat transfer degree of the upper wall due to the advanced appearance of the gas-like film. Increasing the mass flow rate and heat flux density can enhance the heat transfer to varying degrees. The research can provide theoretical reference for mixed working medium heat exchangers in hydrogen-doped natural gas transmission and power circulation systems.

The fuel adaptability of a certain type of gas turbine combustion chamber is systematically investigated in response to the characteristics of blast furnace gas composition and its significant fluctuations in its calorific value. By coupling the detailed chemical reaction mechanism with numerical simulation methods, the comprehensive performance characteristics of the gas turbine combustion chamber under different calorific values and composition conditions were obtained, with a focus on analyzing the distribution of temperature and concentration fields and their influencing mechanisms. The results show that, under the same initial conditions and fuel calorific value, as the volume fraction ratio of H₂ to CO in the gas increases, the average temperature at the combustion chamber outlet decreases from 1 769.35 K to 1 710.11 K, the temperature distribution coefficient decreases from 0.044 to 0.016, the NO_x emission concentration at the outlet decreases from 7.56×10^–6 mol/m³ to 1.49×10^–6 mol/m³, and the CO emission concentration decreases from 993.98×10^–6 mol/m³ to 421.95×10^–6 mol/m³, and the combustion efficiency increases from 98.48% to 99.14%. As the volume fraction ratio of CO₂ to N₂ in the gas increases, the average temperature at the combustion chamber outlet decreases from 1 739.30 K to 1 694.99 K, the temperature distribution coefficient fluctuates in the range of 0.032~0.045, the NO_x emission concentration at the outlet decreases from 3.18×10^–6 mol/m³ to 1.39×10^–6 mol/m³, the CO emission concentration increases from 633.73×10^–6 mol/m³ to 832.45×10^–6 mol/m³, and the combustion efficiency decreases from 98.89% to 98.56%. In addition, as the fuel calorific value increases, the average temperature at the combustion chamber outlet significantly increases from 1 587.30 K to 1 862.39 K, the temperature distribution coefficient shows a downward trend, the NO_x emission concentration increases from 0.29×10^–6 mol/m³ to 18.66×10^–6 mol/m³, the CO emission concentration increases from 459.25×10^–6 mol/m³ to 1 030.61×10^–6 mol/m³, and the combustion efficiency decreases from 99.14% to 98.33%. Finally, 20 sets of data are selected for nonlinear surface fitting. For the blast furnace gas with a heat value range of 3~5 MJ/m³, all the the R² values of the fitting formula are greater than 0.90, indicating this formula can provide a theoretical basis for the control of low-heat-value fuels in gas turbine combustion chambers.

The structural characteristics of once-through steam generators and throttling assembly in the demonstration project of high-temperature gas cooled reactors were introduced, and the reasons and influencing factors of sediment blocking the throttling holes were analyzed. Moreover, the deposition law of corrosion products on the throttling holes of steam generators in high-temperature gas cooled reactors was studied by dynamic cyclic tests at high temperatures and high pressures, including the effects of different iron sources, iron mass fractions, flow rates, and pH values on throttling hole deposition. The results show that, free iron is the main precursor of throttling pore sediments. The phenomenon of throttling hole sediment increases with the iron mass fraction in water. With the increase of local flow velocity, the sedimentation rate of throttling hole increases at first and then decreases, and there exists a maximum deposition velocity range. As the pH value of the water increases from 9.1 to 9.7, the phenomenon of throttle hole deposition intensifies. It is found that appropriately reducing the pH value of feed water and optimizing throttle hole structure size (adjusting flow rate) are effective methods to inhibit the deposition and blockage of steam generator throttling components.

Based on the design and operational conditions of Guangdong Huaying LNG Terminal and its surrounding industrial environment, a cascade utilization scheme integrating thermodynamic power generation with shallow cold storage was developed. Moreover, key process parameters were modeled and solved using HYSYS software to enhance energy efficiency and maximize cold energy utilization. The results show that, under the condition of minimum daily send-out (228 t/h), the original single-stage thermodynamic cycle coupled with cold storage achieved an annual power generation exceeding 32.83 GW·h while meeting the cooling demand of a 7 500 m³ cold storage facility. The optimized scheme adopts a two-stage thermodynamic cycle with shallow cold storage, via employing a 40% (weight percentage) ethane and 60% (weight percentage) propane mixed working fluid, and elevating heat source temperature, this improved design increased the annual power generation to 62.04 GW·h, and raised the net power output per unit mass of LNG from 17.54(kW·h)/t to 33.02 (kW·h)/t, with estimated annual electricity cost savings of approximately 53.641 million yuan. Although multi-stage heat engine cycles can reduce irreversible losses caused by temperature differences, considering factors such as cost-benefit ratio and operational reliability, the second scheme demonstrates strong engineering feasibility and economic viability by closely aligning with the actual conditions of the Huaying LNG Receiving Terminal. Both cascade utilization designs demonstrate distinct advantages for different development stages of the receiving terminal and different evaluation indicators for LNG cold energy utilization, providing valuable references for post-commissioning cold energy applications.

The effectiveness of a data-driven model relies on the completeness of its training samples. For operating conditions beyond the scope of the training samples, the model’s generalization ability is compromised. Therefore, to develop a condenser model that can adapt to the wide load variation of the unit, it is essential for the training samples to involve a diverse range of power generation loads and ambient temperatures. However, achieving this complete dataset is difficult for newly-commissioned units because of their short operation time. To address these challenges, a method for characterizing condensing units using multi-fidelity data and transfer learning is proposed, even with incomplete data. In this method, a pre-trained model is firstly built based on the comprehensive operational dataset collected from a similar unit. On the basis of the pre-trained model, additional linear and nonlinear calibration networks are introduced. The calibration networks are updated through the incomplete data of newly constructed units, enabling the transfer of the pre-training model to the feature space that is adapted to the incomplete dataset. The effectiveness of this method is validated through the condenser of a 1 000 MW supercritical unit. The results indicate that, even with limited training samples, the method accurately predicts parameters such as condenser pressure and circulating water outlet temperature, with an average R² of 0.95, significantly outperforming the conventional data-driven model based on a single data set, of which the average R² is only 0.81.

Based on the concept of high efficiency of gas turbine variable back pressure operation regulation, a high back pressure gas turbine combined cycle power generation system scheme is proposed, in which a pre-compressor and an expander are set in front and behind the main top cycle respectively to maintain and regulate the gas turbine exhaust pressure. Key parameters of the combined cycle are designed based on the initial parameters of the F-class gas turbine, and the case and characteristic analysis are carried out for the temperature of recirculated gas (divided into two conditions: cooling to normal temperature and not cooling), the main top cycle pressure ratio and the gas turbine back pressure. The results show that, the combined cycle efficiency of the recirculated flue gas cooling is not as high as that of the non-cooled flue gas cooling, which is 58.07% and 58.94% when the turbine back pressure is 0.30 MPa. The exergy loss rate of the main compressor is lower because the exit temperature of the main compressor is higher when the recirculated flue gas temperature is higher. When the gas turbine back pressure is 0.30 MPa, the maximum pressure ratio of the combined cycle system efficiency is 17.0, the corresponding combined cycle efficiency is 58.97%, and the specific work is 563.87 kJ/kg. Considering the specific work comprehensively, the recommended main top pressure ratio is 15.4, and when the turbine back pressure is from 0.03 MPa to 0.35 MPa, the variation range of the combined circulation efficiency under the two conditions is about 56.00%~58.57% and 55.81%~59.12%, respectively, which increases at first and then decreases, and the variation range of the combined efficiency is not large at high back pressure. At the same time, based on the practical engineering application, the design of a single waste heat boiler is considered, and its thermal characteristics and possible flexible, low-cost and efficient utilization of renewable energy are analyzed, which provides a new system scheme reference for the flexible and efficient modern combined cycle with multi-energy complementarities.

The Brayton cycle is widely recognized as a key power cycle in the third-generation solar thermal power generation technology. Leveraging the strengths of artificial neural network methods for importance evaluation and quantitative analysis, this research employs a control variable approach to identify critical parameters, including turbine inlet temperature and compression ratio, from a range of operating parameters. In this method, the significance of parameters increases as the R² value decreases. Notably, when excluding these key parameters, the R² values fall to 0.57 and 0.64, respectively, both are lower than other operating parameters. Furthermore, the quantitative analysis of output power in the Brayton cycle yields exceptional results, achieving an R² value exceeding 0.999. The R² values for thermal efficiency and input heat are 0.992 and 0.988, respectively. Finally, the multi-objective optimization results suggest optimal settings of 500 ℃ for turbine inlet temperature and 2.19 for the compression ratio, corresponding to a thermal efficiency of 46.58%, output power of 100.97 kJ/kg, and input heat of –176.5 kJ/kg. This study offers valuable insights for the operational efficiency and performance assessment of the Brayton cycle in solar thermal power plants.

In modern power systems, unit coordinated control faces complex dynamic characteristics and is influenced by faults and external disturbances. To address this challenge, a fault-tolerant control scheme designed for unit coordinated control systems under fault conditions is proposed. Firstly, the transfer function of the unit system is derived using mechanism analysis, and a mathematical model incorporating actuator faults is developed. This model enables the analysis of transient response, stability, and dynamic performance of the system. Secondly, by integrating adaptive techniques with H_∞ control theory, an adaptive fault-tolerant guaranteed-cost tracking control method is designed. This method can automatically compensate for degraded signals when faults occur in the system while further enhancing the robustness and fault tolerance of the system through performance indicator optimization. It satisfies the combined requirements for tracking accuracy and dynamic response. Finally, a simulation is conducted using a 300 MW unit coordinated control system as an example. The results demonstrate that, compared with the conventional fault-tolerant control methods, the proposed approach exhibits superior dynamic tracking performance, disturbance rejection capability, and fault recovery ability. This study provides a reliable control solution for ensuring the safe and stable operation of unit systems in power systems.