To improve the energy efficiency of high‑pressure water jets in ship rust removal operations，a high‑pressure gas‑liquid mixed jet nozzle was designed.Numerical simulation of the designed nozzle structure was conducted using LES and VOF methods.A comparative analysis was performed on the jet flow velocity，liquid phase distribution，liquid phase interface，and pressure on the impact target surface with and without aeration.Nozzle derusting experiments were carried out to verify the influence of the aeration process on jet performance.The results indicate that the aeration process significantly affects jet characteristics.By entraining air，momentum exchange occurs within the jet，enabling it to maintain a higher flow velocity in the throat.Under a water jet pressure of 195 MPa，the average flow velocity in the throat is approximately 400 m/s.Simultaneously，the aeration process promotes jet breakup into discrete droplets within the throat，forming a high‑energy gas‑liquid mixed jet that enhances the jet impact pressure.The maximum instantaneous impact pressure reaches 317.7 MPa，and the average impact pressure reaches 165.8 MPa，representing a 30.8% increase compared to the average impact pressure generated by a free jet.Compared to the inlet pressure，the average impact pressures of the aerated jet and the free jet decreased by 15.0% and 35.0%，respectively.This demonstrates that the aeration process helps reduce the attenuation of jet impact pressure.Under the premise of achieving the same impact effect，the aerated jet can reduce equipment operating pressure to some extent，which is beneficial for improving equipment reliability.Experimental results further validate the performance of the aerated jet nozzle.The findings provide guidance for the engineering application of aerated jets.

To address the issue of degraded insulation performance and non‑uniform temperature field on the outer wall of cryogenic vessels due to flow field reconstruction on the outer surface induced by environmental wind speed during the application of vacuum multi‑layer insulation （MLI），a heat transfer model for a high‑vacuum multi‑layer insulation fast‑fill cryogenic vessel was established.The influence patterns of wind speed conditions on the vessel's temperature distribution characteristics and insulation performance were systematically analyzed.By employing a layer‑by‑layer numerical iterative algorithm for heat transfer，the heat transfer characteristics of each insulation layer within the MLI were revealed，clarifying the changes in the heat transfer mechanism of the multi‑layer insulation structure under different wind speeds.The research results indicate that within the wind speed range of 0~5 m/s，radiative heat transfer within the MLI significantly increases with higher wind speeds，leading to a noticeable rise in the outer wall temperature of the cryogenic vessel，with a 42% increase in specific heat flux.When the wind speed exceeds 5 m/s，the changes in temperature and heat leak tend to level off.At this stage，radiative heat transfer accounts for more than 50%，becoming the dominant heat transfer mechanism.This study provides a theoretical basis and technical support for the non‑destructive testing of heat leak in cryogenic vessels and their installation site selection.

The fluid dynamic pressure wavy‑tilt‑dam mechanical face seal has become a key component ensuring the long‑term stable operation of nuclear main pumps due to its controllable leakage，stable performance，and high reliability.This paper systematically reviews the research progress of fluid dynamic pressure wavy‑tilt‑dam mechanical seals for nuclear main pumps both domestically and internationally.Although relevant research in China started relatively late，driven by the national nuclear power development strategy，domestic research has achieved a transition from following to running in parallel with international efforts.Concurrently，advancements in computational technology have deepened the study of seal friction and lubrication theory.At present，theoretical models for wavy‑tilt‑dam face seals primarily focus on three major subjects：the fluid characteristics of the liquid film，the fluid‑structure interaction between the seal face and the liquid film，and the interaction between the seal ring and the fluid medium.The research paradigm is expanding from single‑physics‑field analysis to multi‑physics‑field coupling simulations.Existing research has been reviewed and summarized from three core perspectives：the design of the fluid film wavy shape，the mechanism of hydrodynamic lubrication，and the collaborative deformation of friction pair components.On this basis，optimization suggestions for future research are proposed：establishing a composite topography fluid film model incorporating roughness and wavy‑tilt‑dam characteristics；developing a hydrodynamic lubrication theory applicable to the coexistence of mixed lubrication and hydrodynamic lubrication；and conducting in‑depth research on the multi‑component collaborative deformation laws specific to nuclear main pump operating conditions，aiming to provide theoretical references for the design and engineering application of high‑performance seals.

With the advancement of electrification and intelligent technologies，higher demands have been placed on human‑centric air conditioning systems.Based on image recognition technology，a deep learning model using ResNet50 as the backbone network and incorporating a spatial attention module （Attention-ResNet50） was constructed for human‑centric air conditioning systems.By collecting infrared image data under different thermal comfort conditions and classifying them into three categories，cold，comfort，and hot，for training and testing，this method significantly improved prediction accuracy.Experimental results showed that the introduction of the spatial attention mechanism increased the overall model accuracy by approximately 5%.The best model accuracy exceeded 94% for male subjects and surpassed 96% for female subjects.The study confirms the effectiveness of the attention mechanism in feature extraction，providing a reliable and universal technical pathway for personalized thermal comfort control.

To address the issue of pressure overshoot during the reversing process of piston pumps，experimental tests and numerical simulations were conducted using coal slurry with a solid concentration of 68.5% as a case study.Cyclic pumping experiments were carried out under two pressure conditions，and the results were compared with numerical predictions.The study revealed that as the distance from the pipeline inlet increases，the rate of decrease in pressure overshoot accelerates，while the overshoot ratio gradually rises.For instance，at a steady‑state transport pressure of 5.17 MPa，the experimental overshoot ratio increased from 11.9% at the inlet to 15.23% near the outlet.Near the pipeline inlet，both maximum velocity and steady‑state velocity demonstrate minimal changes with distance，but beyond a certain point，the maximum velocity incrementally rises.Furthermore，the velocity overshoot at measurement point 11^# under the two conditions is 66.9 mm/s and 17.3 mm/s，with overshoot ratios of 1.53% and 0.43%，respectively.The variation in overshoot magnitude was more pronounced than that of the velocity itself，with the transport velocity differing by 9.5%，while the overshoot ratio differed by as much as 255%.The findings provide valuable insights for optimizing the pumping strategy and the design of coal slurry pipeline systems.

To address the challenges of lightweight and compact design in current spray devices caused by complex internal flow channel structures，multiple liquid supply pipelines and interfaces，and large space occupation，a nozzle structure design concept based on the integration of the inlet channel，swirl chamber，and orifice was proposed.A compact micro‑mist nozzle with a thickness of 5 mm was designed，and an experimental setup for measuring spray characteristics was established to investigate the influence of the compact micro‑mist nozzle's geometric structural parameters on atomization characteristics.The research shows that the flow rate and spray angle are significantly affected by the orifice diameter.Increasing the swirl chamber diameter reduces the liquid film breakup length，which is beneficial for achieving the primary atomization process within a shorter distance.At a spray height of 15 mm，the peak axial velocity of the compact micro‑mist nozzle is greater than 10 m/s，occurring inside the spray cone.When the swirl chamber diameter is small，the axial velocity proportion of droplets at the spray center is the largest.When the orifice diameter is large，the decay of the axial velocity proportion along the radial direction slows down.The sauter mean diameter of droplets from the compact micro‑mist nozzle is less than 40 μm.The droplet size and droplet number density distribution are less affected by the swirl chamber.An increase in orifice diameter results in a 25% increase in the proportion of droplets with a size below 20 μm.This study provides a new approach for achieving integrated and highly compact designs of atomization devices.

To suppress temperature fluctuations inside open‑type food refrigerated display cabinets caused by periodic defrosting，an optimized scheme of installing phase change cold storage materials （PCM） in the cold air ducts was proposed.By analyzing the temperature characteristics of the cold air ducts，ND-1 type PCM with a phase transition temperature of -3 ℃ was selected.The dosage of PCM was calculated based on the refrigeration system load，and the PCM was encapsulated into food‑grade cold storage packs and integrated into the cold air ducts.Under conditions of 25 ℃ and 60% relative humidity，the refrigeration performance of the refrigerated display cabinet before and after installing PCM was compared.The results show that compared with before the improvement，the vertical temperature uniformity of food packages on the first，third and fifth layers in the cabinet after the improvement has increased by 27.6%，21.2%，and 37.8% respectively，and the horizontal temperature uniformity has increased by 58.2%，15.9%，and 24.4% respectively.The average temperature of refrigerated food decreases by 1.12 ℃，the air curtain thermal suction coefficient decreases by 15.9%，the total energy consumption of the cabinet decreases by 6.2%，and the average air velocity attenuation rates at the supply and return air outlets decrease by 2.5% （supply air） and 6.5% （return air），respectively.This scheme effectively stabilizes the internal temperature field of the cabinet and improves energy efficiency.This study can provide a reference for the optimal design of food refrigerated display cabinets.

Aiming at the leakage problem of large vertical mixed flow pump，combined with its specific working conditions，a split type magnetic fluid sealing device was designed for easy disassembly and installation，and the magnetic field simulation of the sealing device was carried out by using the finite element analysis software.Training samples were designed using latin hypercube sampling across the range of critical structural parameters.BP neural networks and genetic algorithms（GA） were utilized to optimize these parameters.An experimental rig was constructed to conduct pressure endurance tests on the optimized seal device.

To improve the operational performance and service life of oil‑free compressors，a study on the friction and wear characteristics of the contact pair between piston rings and cylinder inner walls was conducted.Cylinder surfaces were coated with Teflon，SiC，and DLC，respectively，and filled PTFE was selected as the piston ring material for sliding friction and wear tests.The results show that the friction coefficient time series curve of the friction pair corresponding to the DLC‑coated cylinder is the most stable，with the lowest friction factor.The surface morphology of the DLC coating is favorable，and the wear rate of the piston ring is the lowest.The average friction coefficient of the friction pair corresponding to the Teflon coating is the lowest （0.074 6），but due to poor adhesion between the coating and the aluminum alloy substrate，wear is relatively severe.Both SiC and DLC coatings exhibit good adhesion to the substrate.The wear mechanism of all friction pairs is predominantly adhesive wear，with PTFE transfer films of varying morphologies formed on the surface of the counterpart during friction.Under room temperature （25 ℃） conditions，the transfer films exhibit a flaky structure，with the most complete transfer film observed on the surface of the DLC‑coated cylinder.This indicates that the DLC coating is a relatively ideal optimization solution for cylinder surfaces.The study provides a theoretical basis for the optimized design of oil‑free compressors.

To improve the performance of cavitation jet well‑cleaning and plugging removal guns，based on the design concept of multi‑cavitation synergy，a high‑efficiency well‑cleaning and plugging removal gun with multi‑cavitation synergistic effect was designed，and the flow field characteristics of the improved and conventional guns were comparatively analyzed.The results show that the performance of the new gun is significantly improved compared to the conventional gun，the inlet velocity of each nozzle layer increases by over 417.65%，the jet velocity correspondingly increases，and the jet core segment becomes longer and wider；the peak turbulent kinetic energy inside the new gun decreases by 26.95%，with less overall turbulent energy dissipation；the wall impact pressure of the new gun increases by 52.59%，indicating stronger jet impact；annular cavitation erosion zones exist around the jet impact area，and the erosion zone of the new gun expands by 195.42%；the new gun adopts a non‑uniform distribution strategy，with the first layer nozzles allocating 50% of the energy and the remaining energy equally distributed between the latter two layers；within the injection pressure range of 10~30 MPa，both the wall impact pressure and the cavitation cloud area of the new gun exhibit a linear growth trend with injection pressure.The research results can provide a theoretical basis for enhancing the field application effectiveness of cavitation jet well‑cleaning and plugging removal technology.