Freshwater scarcity is a major global challenge. Solar-driven interfacial desalination technology, as a clean and sustainable solution, offers significant potential for alleviating the water crisis. However, existing interfacial evaporators commonly suffer from bottlenecks, including limited photothermal conversion efficiency and insufficient long-term stability. This paper reports a carbon black (CB)-modified polydimethylsiloxane (PDMS, CB@PDMS) composite interfacial evaporator fabricated by replica molding with a picosecond laser-processed Al template. Leveraging the broad-spectrum, excellent light absorption capacity of CB and the low thermal conductivity of PDMS, excellent seawater evaporation performance was achieved. Experimental results show that the interfacial evaporator attains a light absorption rate exceeding 95% across a broad spectrum (200–2500 nm), with a photothermal conversion efficiency of approximately 85%. Under 1 kW·m−2 indoor solar irradiation, the as-prepared CB@PDMS solar evaporator achieves an evaporation rate of 2.48 kg·m−2·h−1, and an output power density of 45.32 mW·m−2. Over an 80h cycling test, it exhibits excellent performance stability with an average evaporation rate of 2.50 kg·m−2·h−1. In outdoor tests, the maximum evaporation rates reached 1.68 and 1.26 kg·m−2·h−1 under sunny and cloudy conditions, respectively. The narrow performance gap demonstrates its capability for efficient all-weather water production. This study provides a new strategy for the fabrication and processing of all-weather solar interfacial evaporation materials, and also offers a feasible technical reference for alleviating energy shortage issues.

Water injection technology can lower the combustion temperature of hydrogen-fueled direct injection (HDI) engines, reducing nitrogen oxide (NOx) emissions. Firstly, this paper constructs a three-dimensional numerical calculation model of an in-cylinder direct injection pure hydrogen engine. Secondly, the calculation accuracy of the numerical model is verified based on experimental data. Finally, two water injection modes are developed for the HDI engine: water intake port injection (WPI) and water direct injection (WDI). These methods are designed to explore the effects of different water injection modes and injection quantity on air-fuel mixture formation, combustion performance, and emission characteristics within the cylinder. The results show that with the increase in water injection quantity, the average pressure in the cylinder gradually decreases, and the combustion performance gradually deteriorates, but the NOx emission also reduces significantly. WDI mode is more effective for reducing NOx emissions than WPI mode. In addition, at a water-to-hydrogen mass ratio (WHR) of 0.5, compared with the non-injected case, WDI mode and WPI mode reduce NOx emissions by 35.5 % and 32.3 %, respectively. The optimal working condition for combining power performance and emission performance is achieved with a WHR of 1.5 using WDI mode. In Case9-WDI-15, the engine exhibits a thermal efficiency of 40.1 %, and the NOx emission is 8.06 g/kWh. The emission of the optimal case is 81.2 % lower than the non-injected case and is nearly at the Euro-V emission standard. The study provides a reference for reducing NOx emissions of direct injection pure hydrogen engines.

Solar-driven interfacial steam generation technology is regarded as an effective method for freshwater production. Nevertheless, conventional evaporators suffer from weak light absorption and a trade-off between high evaporation rate and salt resistance, which restricts their practical applications. Herein, we developed a picosecond laser-modified gradient Fe3O4@polydimethylsiloxane (LG-Fe3O4@PDMS) interfacial evaporator fabricated via layered curing combined with laser processing. This evaporator features a gradient composition along its thickness direction. The upper layer with a high Fe3O4 content serves as the photothermal conversion layer, while the underlying PDMS substrate suppresses heat conduction toward the bulk water at the bottom. The periodic grooved arrays on the surface enhance light harvesting via multiple light reflections and scattering and simultaneously enable the enrichment of Fe3O4 particles on the evaporation surface. The LG-Fe3O4@PDMS exhibits a light absorptivity of nearly 98% across the full solar spectrum of 250-2500 nm, accompanied by outstanding photothermal temperature rise performance and hydrophobicity. Under 1 sun illumination (1 kW m-2), the evaporation rate reaches 2.79 kg m-2 h-1. In addition, the material retains 72.4% of its original evaporation performance even in a 25 wt % high-salinity solution. Seven-cycle stability tests verify its outstanding resistance to salt crystallization. The design concept of this gradient composite structure offers a simple and feasible strategy for fabricating high-performance and long-term stable interfacial evaporators, as well as for practical applications in seawater desalination and organic wastewater purification.

Abstract The purpose of this study is to improve the performance of high-precision robot joints in terms of control accuracy and running stability, focusing on the adaptive control and optimal design of permanent magnet synchronous motor. In view of the influence of time-varying disturbance and measurement noise, this study gives a strict stability proof to ensure that the system meets the uniform ultimate boundedness (UUB), and corrects the misjudgment of traditional analysis methods under nonlinear conditions. By constructing a response surface model with sensitive weight of magnetic parameters, the accuracy and optimization range of the model are improved, and the total harmonic distortion of stator current is included in the optimization target. The simulation incorporated the nonlinear characteristics of the inverter. To assess the rationality of the motor structural design, a quantitative evaluation framework was established, and a dedicated simulation module was developed to verify joint control accuracy and operational stability. This study thereby achieved a closed-loop analysis spanning motor optimization and system-level performance validation. These extensions effectively fill the analysis gap in the process of transforming control algorithm and motor performance into actual robot joint application. The results suggest that the improved algorithm empowers accurate parameter identification. The motor efficiency increased from 91.50% to 91.95%, while the cogging torque decreased from 148.51 mN·m to 20.84 mN·m, representing a reduction of 85.99%. In the joint-level simulations, low-speed velocity fluctuations were suppressed to below 1.2%, and the root-mean-square tracking error at high speeds was reduced by 35%. Comparative analyses with recursive least squares and the non-dominated sorting genetic algorithm III (NSGA-III) verified the effectiveness and superiority of the proposed method. These findings provide simulation-based evidence supporting the practical compatibility and potential application value of the proposed approach in high-precision robotic joint systems.

Ammonia engines have received widespread attention due to zero-carbon emission advantages. However, the practical applications are limited by drawbacks such as difficult ignition, slow combustion, unstable combustion, and low power performance. The active pre-combustion chamber (PCC) jet ignition technology is capable of effectively enhancing the ignition and combustion stability of ammonia, accelerating the combustion speed of ammonia, and improving the power performance of the engine. Therefore, this paper builds a three-dimensional (3D) numerical computational model of a jet ignition ammonia engine with an active PCC. The dependability of the model is confirmed by experimental data. Then, considering that the jet ignition chamber structure significantly affects the airflow movement and flame propagation process in the PCC and cylinder, four active PCC structural schemes are designed for this purpose. The internal flow, combustion performance, and emission characteristics of the engine are investigated under different active PCC structure schemes. The results show that the upper part configuration of the PCC greatly influences the vortex structures inside the PCC. And the incylinder vortex strength is related to the structure of the PCC lower part, the vortex strength is maximum when the lower part of the PCC is a parallel-convergent structure and minimum when the lower part of the PCC is a convergent structure. Comprehensively considering the combustion and emission performance of the engine, Case 1 (upper part convergent, lower part parallel-convergent configuration) emerges as the optimal structural scheme. The indicated mean effective pressure and indicated thermal efficiency reached their maximum values in Case 1, at 0.539 MPa and 38.45 %, respectively. In comparison with the minimum Case 3 (upper part parallel, lower part convergent configuration), these performance metrics are elevated by 19.78 % and 8.86 %, while nitrogen monoxide and unburned ammonia emissions are reduced by 3.15 % and 79.49 %, respectively. This study provides a reference for the efficient and clean combustion of jet ignition ammonia engines.

s: Direct injection coupled with lean burn technology represents a pivotal advancement in effectively addressing combustion and emission control in hydrogen engines. Additionally, incorporating ammonia in specific proportions enhances the indicated effective pressure and thermal efficiency of the engines. This study employs a numerical simulation approach to build a three-dimensional spark ignition engine model using hydrogenammonia premixed fuel with direct injection, subsequently, validating its accuracy. The influence of the hydrogen-ammonia premixed mass ratio (Ra) and the equivalence ratio (4b) on the mixture formation, combustion process, and emission of in-cylinder under direct injection and lean burn conditions are studied. The results indicate that the addition of ammonia facilitates a more uniform distribution of hydrogen within the cylinder. Notably, in cases where 4b >= 0.45, a small percentage of ammonia (Ra <= 30 %) can shorten the hydrogen combustion duration by 1 to 3 crank angle degrees. Conversely, in cases with 4b <= 0.40, ammonia inclusion exhibits a suppressive effect on hydrogen combustion, with the impact becoming more pronounced at a lower equivalence ratio. On the emissions side, heightened nitrogen oxide emissions concentration correlates with increased ammonia. In all cases, evaluating overall engine performance reveals that a 4b of 0.40 with a Ra of 10 % emerges as the optimal program, achieving an indicated thermal efficiency of 47.1 % and oxide emissions of 9.34 g/kWh.

The low efficiency of thermoelectric generators has become a major obstacle to their widespread application. To improve the efficiency of the thermoelectric generator, this paper focuses on the multi-objective optimization for a segmented annular thermoelectric generator with the biconical structure. First, a numerical model of the thermoelectric generator is developed, and its accuracy is validated using experimental data. Second, through response surface methodology, the conical angle B, leg angle (1, leg angle ratio S, and resistance ratio w are selected as design variables, while power, exergy efficiency, and safety factor are chosen as response objectives to obtain the relationships between the response objectives and the design variables. Finally, multi-objective optimization is performed using the Grey Wolf Optimization algorithm, and the optimal structure is determined with the Technique for Order Preference by Similarity to Ideal Solution. The results show that the coefficient of determination R2 of the regression equation constructed using the quadratic model in the prediction of thermoelectric generator performance is greater than 0.9, indicating that the model has a high goodness of fit. The findings indicate that the optimal values for B, (1, S, and ware 3.51 degrees, 4.00 degrees, 1.02, and 1.21. The performance of the optimized structure is P = 16.43 x 10-3 W, nEx=11.80 %, and S = 2.09. The optimal structure results in a 32.18 % increase in power and a 15.12 % improvement in exergy efficiency as opposed to the conventional thermoelectric generator. This study combines three methods to provide a new idea for the structural optimization design of thermoelectric generators.

Lithium-ion batteries may experience thermal runaway due to excessive temperature rise when operating at high discharge rates. By incorporating composite phase change materials (CPCMs) onto the battery surface, it is possible to effectively regulate the temperature, ensuring it stays below critical safety limits. In order to obtain CPCM with optimal stability and high thermal storage performance, this study proposes an N-doped metalorganic frameworks (MOFs) derived hierarchical porous carbon loading material. Specifically, g-C3N4 was utilized as a nitrogen source to dope MOF-199, leading to the synthesis of N-doped porous carbon (NC-X). Further treatment with concentrated nitric acid enriches the pore structure, yielding N-doped hierarchical porous carbon (NCN-X). After impregnation with lauric acid (LA), shape-stable CPCM (LA/NCN-X) was obtained. The results show that the performance characteristics of the CPCM vary with the amount of g-C3N4 incorporated. When the g-C3N4 content reaches 20 %, the CPCM exhibits peak values in effective loading ratio, crystallinity, and impregnation efficiency. The CPCM achieves a maximum loading ratio of 70.17 %, with a latent heat of 125.12 J center dot g(-1), representing 94.01 % of its theoretical latent heat value, and a thermal storage efficiency of 99.16 %. Moreover, when the lithium-ion battery undergoes discharge at 3C, the surface temperature of the battery is reduced by 17.52 % for CPCM-G compared to BC-G, providing enhanced safety for the battery under high discharge rate conditions.

The application of ammonia-diesel dual fuel can significantly reduce the emission of greenhouse gases, with the ammonia supply mode and ammonia energy ratio being important factors that influence the characteristics of ammonia-diesel dual-fuel engines. In this study, a 3D numerical model of an ammonia-diesel dual-fuel engine with coupled chemical reaction kinetics is established, and the reliability of the digital model is tested based on experimental data. Then the impact of ammonia energy ratio on the mixture formation, burning process, power and exhaust performance of an ammonia-diesel dual-fuel engine in ammonia premix and direct injection modes is investigated. The results indicate that when the ammonia energy ratio is 80 %, the highest indicated thermal efficiency is 47.22 % in the ammonia direct injection mode, while the lowest greenhouse gas emission is 459.32 g/kW & sdot;h in the ammonia premixed mode. Comprehensively analyzing the engine characteristics, the ammonia direct injection mode with an ammonia energy ratio of 80 % is the preferred option. Compared to the pure diesel condition, it exhibits an increase in indicated mean effective pressure by 4.10 % and an increase in indicated thermal efficiency by 2.57 %, respectively, while resulting in a reduction of GHG emissions by 8.31 %. This research can provide a reference to the design and optimization of fuel control strategies for ammonia-diesel dual-fuel engines.

To better investigate the bonding strength of Fe-based cladding layer with varying WC contents coating on AISI H13 substrate, this study comprehensively considered the laser cladding process and results, as well as the stress distribution on the fracture surface during cladding layer fracture. Firstly, a coupled thermal flow numerical model considering process parameters, molten pool dynamics, Marangoni effect, and solid-liquid phase transformation was established to study the laser cladding process and results. This model was used to optimize the design of the experimental mold for bonding strength. Secondly, a large strain fracture numerical analysis model was established to study the stress distribution on the fracture surface during cladding layer fracture, which helped to determine the critical dimensions of the experimental specimen for bonding strength. Finally, bonding strength experiment was conducted using the optimized experimental mold and specimen. The shear strengths of Fe901 powder coating on H13 substrate without WC addition, with 5 wt% WC addition, and with 10 wt% WC addition are 733.81 MPa, 674.64 MPa, and 544.69 MPa, respectively. Fractographic analysis revealed that the overall fracture mode of the Fe901 cladding layer is a mixture of ductile dimple fracture and quasi-cleavage fracture. The fractographic analysis of the 5 wt% WC + Fe901 cladding layer is predominantly quasi-cleavage, with reduced interface bonding strength and toughness, but still in a mixed fracture form. The fractographic analysis of the 10 wt% WC + Fe901 cladding layer almost shows a completely cleavage morphology, indicating a complete transition to brittle fracture.

The flow field design significantly influences the performance of the proton exchange membrane fuel cell (PEMFC). Inspired by the arc-shaped structure and staggered arrangement of fish scales, a fish scale bionic flow field (FSFF) is designed, which potentially reduces flow resistance and enhances flow field uniformity. Thus, a three-dimensional numerical model is established and validated with experimental data. To clarify the feasibility of the novel flow field design, different flow directions and arrangement modes on flow characteristics and species distribution are studied. The results show that all FSFF schemes can effectively improve oxygen distribution and enhance PEMFC performance by compared with conventional parallel flow field (CPFF) and conventional pin-type flow field (CPTFF). Especially, the scheme of FSFF-FB which adopts forward flow and subchannel arrangement B achieves a 9.3 % and 1.41 % increase in power density, along with a 5.47 % and 1.38 % reduction in pressure drop. Then, we design and study four subchannels number (6, 8, 10 and 12) and find that the scheme of FB-10 with 10 subchannels is better, its effective mass transfer coefficient increased by 27.70 % and 17.16 %, respectively compared to CPFF and CPTFF. Overall, increasing the subchannel numbers improves the power density, however, the pressure drop also increases.

To enhance the wear resistance of H13 steel surfaces, a Fe901 cladding layer was applied to the surface of the H13 steel. A pin-on-disk friction and wear tester were employed to simulate the differential temperature environment during hot stamping. The Fe901 cladding layer and the H13 steel quenching layer with high-temperature GA plate were compared to indicate the friction and wear properties. To study the phase, microstructure, and wear mechanism of pins and disks, a scanning electron microscope, energy-dispersive spectroscopy, and x-ray diffraction analyses were employed. The results demonstrate that the M23C6 and M7C3 hard phases increase the hardness of the Fe901 cladding layer; at 600, 700 and 800 °C, compared with the quenched pin, the friction coefficient of the Fe901 cladding pin decreased by 5.5

End-effector self-reconfiguring live working robot autonomously replaces the end actuator of the robot arm for different tasks, and at the same time completes high-altitude work tasks according to the designed motion plan. In order to ensure uninterrupted operation on power transmission lines, the research methods to enhance the efficiency of robot arm work while reducing energy consumption is of significant importance. Based on this, the paper proposes a time-energy optimal trajectory optimization method for a six-joint robotic arm of a reconfigurable robot for power line maintenance based on Fourier series, taking into account the influence of both robot kinematics and dynamics on the motion trajectory, the positions, velocities, accelerations and joint torques are all considered as constraints. Time and energy are chosen as objective functions. By utilizing the Lagrangian equation method establish an energy-based robot dynamic model in generalized coordinates. The motion curves of each joint are obtained by the cubic spline interpolation method in the joint space, and the boundary conditions of the motion curves are optimized by Fourier series, so as to establish the optimal trajectory mathematical model. The time-energy optimal trajectory planning problem is transformed into a convex optimization problem, the DTW (Dynamic Time Warping) algorithm is used to regularize the difference between the time function and the energy function in the displacement sequence under the known trajectory, and the number of terms in the Fourier series of the minimum hour of the objective function is obtained by the GA-DQN (Genetic Algorithm-Deep Q-Network) algorithm. Finally, with the actuator replacement at the end of the robotic arm as the operation objective, the time-energy optimal trajectory is obtained from the desired positional attitude at the initial and termination of the end of the robotic arm. Simulation analysis is carried out under MATLAB and compared with the motion trajectory obtained by the fifth degree polynomial interpolation method, and the results show that by optimizing the motion trajectory with Fourier series, the motion time is shortened by about 35.67% and the energy consumption is reduced by about 39.63%. And online experiments were conducted in the field to measure the output errors of joints 2 and 5, as well as the actual energy and time consumption of outputting the optimal trajectories, which verified that the trajectories obtained under this optimization algorithm have better performance and can meet the requirements of online robot end self-reconfiguration operation.

To solve the problems of response lag and limited generalization of a single algorithm in traditional control methods for robotic arm trajectory tracking, a hierarchical control architecture is proposed. The upper layer adopts a soft actor critic algorithm optimized by multi actor critics to generate robust trajectories. The lower layer achieves precise tracking through the sparrow search algorithm proportional integral derivative feedforward compensation controller. The results show that the improved soft actor critic algorithm achieves average reward values of 1165 and 1087 in obstacle free scenes, with success rates of 88.65% and 83.54%, respectively, which are superior to other compared algorithms. Meanwhile, the root mean square error of the algorithm in different scenarios is only 0.18 rad s-1 and 0.24 rad s-1, respectively, and the single trajectory time is only 0.68 s and 0.77 s, achieving high-precision and high-efficiency robust trajectory generation. In addition, the sparrow search algorithm proportional integral derivative feedforward compensation controller has the highest degree of joint angle tracking coincidence, and its Z-axis contact force fluctuates around the expected value, with a lower fluctuation range than other methods, ranging from 6.78 N-7.36 N in scenario 1 and 6.52 N-8.13 N in scenario 2. This architecture achieves the synergy of global optimization and precise tracking, suitable for 3-6 axis serial industrial robotic arms, providing important reference for high-precision trajectory tracking of multi degree of freedom robotic arms.

The optimization of the structural parameters of the membrane electrode (MEA), as the core component of the proton exchange membrane fuel cell (PEMFC), is crucial for improving the cell performance. In this study, a numerical model of the serpentine coiled flow field (SCFF), which represents the central diffusive flow field, and the serpentine parallel flow field (SPFF), which represents the conventional inlet and outlet flow field at the edges, is constructed. After verifying the model accuracy by experimental data, the thickness of diffusion layer (GDL), catalytic layer (CL) and proton exchange membrane (PEM) are taken as design variables, and based on the indexes of power density, concentration polarization overpotential and water content of the membrane, we construct the CFD numerical simulation, ANOVA, RSM response surface method and NSGA-II multi-objective optimization algorithm are used as the collaborative analysis framework to systematically investigate the influence of membrane electrode parameters on cell performance under different flow fields. For the first time, the research incorporates the flow field structure type into the membrane electrode parameter design system, breaking the traditional paradigm of independent optimization of flow field and membrane electrode, and forms a parameter optimization method coupled with multiphysical fields through single-factor sensitivity analysis and multi-factor interaction analysis. During the optimization process, the Pareto solution set is obtained by the NSGA-II algorithm, and combined with the results of significance analysis, new indicators such as GDL liquid water saturation, uniformity index, and membrane proton conductivity are added to construct a framework for evaluating the water management capability covering six key dimensions, and to realize the cross-type comparison of the structural parameters of membrane electrodes after the optimization of the two types of flow fields. The results show that: the catalytic layer thickness has a more significant effect on the power density, concentration polarization overpotential and membrane water content than GDL and PEM; the center-diffusion SCFF is superior in the output performance, mass transfer capability and water management capability compared with the traditional SPFF, and the thickness of its optimized CL and PEM is much thinner, which can effectively reduce the cost of MEA fabrication. The quantitative analysis method of concentration polarization overpotential proposed in this study deepens the study of mass transfer process from the coupling mechanism of reaction kinetics and mass transfer thermodynamics, and provides a new perspective and important reference for the synergistic design of flow field and membrane electrode.

Ammonia (NH3) is a zero-carbon fuel for use in internal combustion engines, however, its poor combustion performance has limited its engineering applications. Hydrogen (H2) is an accelerant to improve NH3 combustion and jet ignition technology can improve combustion stability. Thus, in this paper, a three-dimensional jet ignition engine simulation model coupled with the NH3/H2 chemical mechanism is established. The combustion characteristics, power, and emission performance of pure NH3 condition and H2-blending condition under different jet hole configurations are studied and compared. The results show that combustion performance is improved by jet ignition technology and blending H2 means. In particular, the configuration of main and auxiliary jet holes can improve the ignition process of the pre-combustion chamber, and the improvement effect of the pure NH3 condition is higher than that of the H2-blending condition. Compared with the single jet hole configuration, the power and emission performance of 4 auxiliary jet holes (Multi-hole-4-NH3) are improved under pure NH3 conditions, while the power performance of only 3 auxiliary jet holes is improved under H2-blending conditions. The Multi-hole-4-NH3 has the best improvement, its indicated mean effective pressure and indicated thermal efficiency are 6.1 % and 5.3 % higher than those of the single jet hole, and the NO emission is 7.1 % lower.

Traditional rigid mandrels are somewhat effective in preventing cross-sectional collapse during the bending of small-radius bimetallic composite tubes, but they are prone to inducing defects such as cracks. This study introduced five plastic mandrels of PTFE, PE, PP, POM and PVC materials, and developed the constitutive model of elastic-plastic deformable bodies that can describe their pressure-sensitive characteristics. Focusing on the bimetallic composite tube with a relative bending radius of 1.76, this research investigated the bending defect characteristics associated with plastic mandrel filling, rigid mandrel filling and non-mandrel filling, from the perspectives of springback, surface cracks, wall thinning and cross-sectional collapse. This study also evaluated the enhancement in bending quality achieved through the use of the five plastic mandrels. Results show that the springback angle of the composite tube is proportional to that of the plastic mandrel, indicating that the utilization of plastic mandrels results in an augmentation of springback angles. But the springback angle can be controlled through overbending techniques. Transverse cracks appear on the surface of the covered tube, regardless of whether a mandrel is used or the type of mandrel employed. Among these mandrels, the PTFE, PE and PP mandrels demonstrate superior performance in reducing crack distribution and wall thinning, with the PP and PE mandrels showing the best results. In contrast, mandrels with higher hardness, such as rigid, PVC and POM mandrels, are effective in preserving the tube’s cross-sectional shape and minimizing cross-sectional collapse, with the POM mandrel being the most effective. Nonetheless, these harder mandrels are less effective in reducing tube damage and wall thinning.

Amidst heightened global focus on climate change and greenhouse gas mitigation, the advancement of clean alternative fuels and high-energy-density power systems has emerged as a critical research priority. In this paper, a non-premixed micro swirl combustor based on micro-thermophotovoltaic (MTPV) system was designed and manufactured. The non-premixed combustion characteristics and radiation performance of the combustor were experimentally and numerically investigated. The flame morphology at confined spaces and free spaces were compared, and the influences of inlet parameters on flame morphology, distribution of wall temperature, composition distribution and radiation performance were systematically studied. It was found that the combustor wall prevented the ingestion of external air into the combustion chamber, reducing the area of the recirculation zones. The flame in the free space was close to jet flame and the flame height decreased with increasing air flow rate. Within confined spaces, the flame exhibits a trumpet-like shape with rough edges, and its height increases with increasing air flow rates. Increased air flow and total flow both reduce combustion stability. Under high flow velocity conditions (Region I) or high equivalent ratio (Region II), the total flow velocity played a major role on the wall temperature. Under low flow velocity and low equivalent ratio (Region III) conditions, the equivalence ratio played a major role in the wall temperature distribution. As the equivalent ratio increases, the radiation energy and radiation efficiency first increase and then decrease. When the equivalence ratio is 0.79 (QH2 is 2 SLM, QAir is 6 SLM), both of radiation energy and radiation efficiency are highest (237 W and 0.56).

The hydrogen engine application is crucial for promoting carbon neutrality, while the hydrogen-diesel rotary engine development can reduce greenhouse gas emissions and promote hydrogen energy diversified utilization. Thus, hydrogen-diesel combined combustion technology is first proposed for rotary engines. Based on the means of parametric modeling, self-programming control and chemical reaction kinetics calculating, the in-cylinder flow and combustion process under different dual-fuel direct injection strategies and hydrogen blending modes are investigated. Results find that adopting the gaseous-liquid dual-fuel direct injection means can simultaneously realize the diesel and hydrogen stratified distribution, and interestingly the combustible mixture in-chamber forms an obvious "gas-in-oil" phenomenon. Specifically, diesel distribution in the front and middle chamber region presents rich in the leading part and thin in the trailing part, while hydrogen distribution in the chamber's middle and back region shows an opposite concentration distribution rule. The hydrogen lower direct injection with gas nozzle position lower the cylinder centerline 50 mm (Case-HLDI) is the optimized application scheme which has the highest peak pressure and that increases by 12.8 % and 11.3 % over the no hydrogen blending mode (Case-NHI) and the hydrogen intake port blending mode (Case-HPI). Moreover, its combustion rate also accelerates by 43.9 % and 17.9 %, respectively.

In order to apply laser cladding technology to the complex surface processing of hot-working dies, this study developed a numerical model for curved surface laser cladding along various scanning trajectories under multi-physics coupling considering the dynamics of the molten pool, cladding parameters (scanning speed and laser power), Marangoni effect, and solid–liquid phase transition. Utilizing this model and by altering cladding parameters, the temperature field and the variation in coating thickness along various scanning trajectories were studied as well as the interaction between the two. The following discoveries were made. Variations in scanning trajectories lead to differences in the coating thickness of curved surface laser cladding. Regardless of the combination of cladding parameters, the coating thickness of scanning from top to bottom is always less than that from bottom to top, with a difference of approximately 0.05 mm. The temperature field and coating thickness influence each other. The Marangoni effect induced by the temperature field is the primary cause of coating thickness growth, while the coating thickness affects thermal transfer from the thermal source, ultimately influencing the temperature field. Employing a greater laser power or a slower scanning speed, or a combination of greater laser power and slower scanning speed, can increase the coating thickness and its maximum temperature in curved surface laser cladding. The model, when contrasted with experimental data, exhibits a comprehensive discrepancy of 3.49%, signifying its high precision and practical engineering applicability.