In order to break through the bottleneck of heat transfer efficiency of traditional printed circuit heat exchangers, a physical model of airfoil PCHE was established, numerical simulations were conducted to study the convective heat transfer of supercritical CO₂ in the model, the heat conduction principles of supercritical CO₂ under varying mass flow rates and inlet temperatures have been analyzed, and by changing the hydraulic diameter of the channel, further study the heat quantity transfer situation. The results indicate that the thermal exchange performance can be improved by increasing the mass flow rate and the inlet temperature of the cold fluid. At varied hydraulic diameter of the passage, the heat transfer capacity of PCHEs with chord lengths of 6 mm and 8 mm both increase with the increase of Reynolds number. When the Reynolds number is between 19 500 and 26 000, PCHEs with chord lengths of 6 mm and 8 mm have similar heat transfer performance; when the Reynolds number is between 26 000 and 50 000, the comprehensive performance of PCHE with a chord length of 8 mm is 2.55% higher than that of PCHE with a chord length of 6 mm. The research results provide a theoretical basis for the structural design of airfoil PCHE.

Poly (arylpiperidine) anion exchange membrane (AEM) has been widely studied in anion exchange membrane fuel cells (AEMFCs) and alkaline electrolyzed water due to their excellent alkali resistance and stability. In this work, poly (triphenyl fluorene piperidine) (PTDP) AEM was prepared from 9,9?diphenylfluorene monomer with distorted large volume structure, and hydrophilic large volume cyclodextrin crosslinking agent (β?CD?Br₇) was introduced on this basis, which can control the microphase separation structure in AEMs. The prepared qPTDP?10?CD₅ AEM with 5% crosslinker content reached a high conductivity (130.2 mS/cm at 80 ℃). After the membrane was treated in 1 mol/L NaOH at 80 ℃ for 2 000 h, its conductivity retention was 94.3%, showing good stability. The H₂/O₂ fuel cell assembled with qPTDP?10?CD₅ yielded a peak power density of 1 490 mW/cm² at 80 ℃. In the durability test, the fuel cell assembled with qPTDP?10?CD₅ showed a voltage retention rate of 89.7% after 30 h, showing good cell performance.

As a new type of clean, carbon?free, sustainable and efficient energy source, hydrogen has great potential in the future energy mix. Hydrogen purification by pressure swing adsorption is the main separation technology for hydrogen production with high purity, low energy consumption and high degree of automation. In this paper the progress in research and application of pressure swing adsorption hydrogen production in theoretical simulation, process control optimization and adsorbent materials were critically reviewed, and the future development of pressure swing adsorption hydrogen production technology was prospected.

In order to improve the fastening effect of the bolt flange of pressure vessel, the structure of the hydraulic wrench and the holding sleeve was improved, and the holding sleeve was optimized, and a new type of fixed wrench was designed. The paper introduced and compared the joint use of hydraulic wrench and holding sleeve in bolt flange fastening operation, improved the structure of the holding sleeve, and analyzed the static structure of the new type fixed wrench by ANSYS. The results show that the structure optimization can effectively improve the fastening effect of flange bolts of pressure vessel.