This study investigates the direct impact of heat transfer on the thermodynamic performance of Micro Swing Rotor Engines (MSRE) through numerical analysis. To comprehensively address the influence of heat transfer, we employ a refined thermodynamic simulation model, incorporating a regressive correlation formula, and introduce a fluid-thermal weak coupling method to yield practical solutions. The numerical analysis reveals that heat transfer has profound effects on the performance of MSRE. Specifically, the temperature cycling curve experiences significant alterations, resulting in an increase in cycle-residual mass by 72.6% and a decrease in intake mass by 10.55% at a working frequency of 100 Hz. The pressure cycling curve is primarily affected during the compression and expansion processes, leading to a substantial rise in pressure during compression (reaching 1.055 MPa) while the contribution of combustion becomes less noticeable. Consequently, these changes increase engine power consumption during compression by 46.41% and reduce overall engine thermal efficiency by 30.23%. Additionally, an increase of the inner wall temperature by 100 K leads to a linear reduction in engine power by 0.1 kW and thermal efficiency by 0.5%. To mitigate these challenges, we propose practical heat management strategies, such as applying heat insulating coatings. The study underscores the critical roles of heat transfer in MSRE operation and provides insights for optimizing its thermodynamic performance, achieving a potential improvement of up to 54.68% in power output and 12.79% in efficiency.

In the micro-clearance of the valves and sealing structures of liquid hydrogen (LH₂) storage tanks, bubbles occur due to heat leakage. The sudden rising of pressure causes bubbles to collapse, resulting in pressure and temperature fluctuations that impact the sealing surface and the valve. In this paper, the cryogen cavitation model is modified by considering the thermal effect, surface tension, and viscosity. The bubble collapse inside micro-clearance is investigated by the modified cavitation model and volume of fluid (VOF) method. Transient pressure and temperature at the bubble center during collapse are recorded and evaluated. The effects of micro-clearance height, dimensionless bubble diameter, and bubble vertical position on bubble collapse and bubble morphology are investigated. To reduce the cavitation erosion on the walls, the frequency and time-frequency characteristics of the pressure oscillations induced by bubble collapse are analyzed by Fast Fourier Transform (FFT) and Wavelet Transform (WT). Furthermore, the temperature and pressure field variation and oscillation mechanisms are analyzed by Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD). The analytical results reveal the LH2 bubbles collapse mechanism within the micro-clearance. The results provide a certain extent of reference for optimizing the structure of micro-clearance.

High temperature and pressure are the main challenges faced in the exploration of deep earth sciences. In order to ensure the safe drilling of high-temperature and high-pressure wells, a thick-walled simulated wellbore device is proposed and its heat transfer characteristics are studied according to the test requirements of pressure bearing exceeds 25 MPa and temperature exceeds 673.15 K. To investigate the dynamic heating process of the fluid within the cylinder, a mathematical model was developed to describe the coupled heat transfer mechanisms. This model incorporates the nonlinear properties of the fluid inside the cylinder. The results reveal that the temperature field distribution during the dynamic coupling heat transfer process is influenced by the electromagnetic induction current and the internal flow within the cylinder. During heating, the liquid transitions from a subcritical to a supercritical state. Buoyancy arising in the heating process affects the temperature distribution within the container and the formation of vortices. Incorporating a cooling system at the top of the container effectively maintains low-temperature operation in the sealing area. Additionally, the study shows that higher currents significantly increase both the final average liquid temperature and the cylinder wall temperature compared to the initial conditions. The proposed model and solution methodology provide a reliable approach for simulating fluid-structure coupled heat transfer in high-temperature, high-pressure well environments, offering a theoretical foundation for designing simulated wellbore heating systems.

As an emerging cooling solution, the technology of using liquid metal as a cooling medium for chips has been the subject of many classic studies. This considerable critical attention stems from the practicality and broad applicability of liquid metal in addressing the thermal management challenges posed by 3D ICs (Three-Dimensional Integrated Circuits). Recognized for its superior heat transfer properties, liquid metal shows significant potential to replace traditional heat transfer fluids. Compared to conventional chip cooling methods, liquid metal-based technologies offer higher heat dissipation efficiency and improved performance. This paper analyses research on liquid metal chip cooling, categorizing the findings into five key areas: cooling medium selection, channel design, drive pump analysis, system performance evaluation methods, and the co-design of liquid metal microfluidic chip heat dissipation systems. The comprehensive review is expected to provide a theoretical reference and technical guidance for liquid metal-based chip cooling technologies.

Solar-driven interfacial water evaporation technology offers a zero-carbon, sustainable solution for extracting clean water from seawater and wastewater, presenting an effective strategy to address the global water crisis. This study has employed finite element simulation to investigate the solar interfacial evaporation process, elucidating the interactions between heat, water, and salt during evaporation. Additionally, the internal water channels of the evaporator are optimized and designed using topology optimization techniques. In this project, a cylindrical evaporator model with vertical micropores is developed from carbon-based polymer materials. The impact of pore diameter and spacing on the evaporation rate is analyzed, alongside the effects of thermal conductivity, solar radiation intensity, and ambient wind speed on the evaporator’s performance. Simulations have revealed that with a pore diameter of 20 μm and a spacing of 0.55 mm, the evaporator achieves the highest evaporation rate of 0.91 kg·m^–2·h^–1. The findings indicate that smaller pore sizes substantially enhance the evaporation rate, while larger pore spacings initially increase, and then decrease the rate. Further optimization involves using 20 μm-diameter round pores and adjusting the cross-sectional shapes of the pores based on topological configurations with a material volume factor of 0.5. The optimized structure demonstrates an evaporation rate of 2.91 kg·m^–2·h^–1, representing a 219.78% increase over the unoptimized design. These optimized structures and simulation results provide valuable insights for future evaporator designs.