To study the breakup atomization and development process of kerosene propellant in crossflow under subsonic conditions, and to realize the accurate numerical simulation of fuel atomization, a kerosene jet in crossflow with average flux-to-momentum ratio q ranging from 7.9 to 46, and average We_g ranging from 5.6 to 120 is selected to enter the mainstream of the air under the velocity conditions of 11 subsonic uniformly incoming air main streams and the phenomenon of primary atomization under the action of crossflow is investigated by the Volume of FluidMethod and Adaptive Mesh Refinement method. The volume of the FluidMethod (VFM) method and Adaptive Mesh Refinement (AMR) method are used to investigate the primary atomization phenomenon under the jet's action in crossflow and verify the accuracy of the numerical simulation method by comparing it with the experimental results. The results show that jet fragmentation of kerosene propellant is mainly caused by surface tension, especially the Rayleigh-Taylor (R-T) instability plays a dominant role. In contrast, the surface fragmentation triggered by the Kelvin-Helmholtz (K-H) stability precedes the liquid column fragmentation caused by the R-T instability. The atomization process is negatively correlated with the mean gas Weber number, positively correlated with and strongly influenced by the mean flux-to-momentum ratio q, and finally an empirical equation for the jet penetration depth profile suitable for atomization in crossflow jet is obtained.

In response to the strategic needs of becoming a leading space power, and against the backdrop of hot topics such as "Airline-Flight-Based transportation of reusable rocket" and the successful in-situ recovery at launch tower during the fifth test flight of SpaceX's Super Heavy-Starship, this study benchmarks against world-class space launch sites, and combines the actual development of Chinese space launch site construction. It refines the basic characteristics that an "Airline-Flight-Mode" launch site should possess, including multi-station parallel operation, fast turnaround launch, high safety and reliability, and low-cost launch. The current gaps in China's space launch site in adapting to "Airline-Flight-Mode" launch are analyzed, and a demand system for building the "Airline-Flight-Mode" launch capability of China's launch site is proposed. At the organizational management level, China's launch site should develop from a single-mode construction and operation to a diversified mode involving national, civilian and commercial entities, while adhering to the concept of a large industrial ecosystem, integrated deployment and collaborative design of satellites, rockets and launch sites should be promoted to achieve "launch upon delivery and reuse upon recovery". At the key technology level, emphasis should be placed on the development of pre-launch rapid refueling, post-launch rapid recovery, special robots, in-situ recovery at launch towers, modular construction, etc., to achieve efficient turnaround, high-frequency launches, and multi-station implementation. The research can support the high-quality development of space launch site planning and construction.

A novel smart bolt combined with fiber EFPI/FBG micro-structures is presented to monitor the state of tightening force of a bolted aerospace structure under high temperature circumstance. In this smart fiber bolt, the fiber EFPI micro-structure is applied to obtain the length variation in the direct of bolt axis under the effect of tightening force. And the fiber Bragg grating micro-structure is applied to obtain the bolt temperature. With the parameters obtained by the fiber EFPI/FBG micro-structures, the tightening force can be obtained through the approach presented. Test samples which are 50mm long M8 bolts combined with fiber EFPI/FBG micro-structures are made and tested by a universal testing machine with a heating chamber. The test results show that the smart fiber bolt presented can be used to obtain maximum 10kN tightening force under the temperature of 500 degree centigrade with maximum relative error 3.1%. This smart fiber bolt can be used to monitor the state of structure connection under high temperature circumstance.

Torque limiter is a physical protection device that ensures mechanical equipment operates under safe load conditions. Conventional engineering design typically employs static design and verification methods, with optimization and iteration carried out through physical prototypes, resulting in long development cycles and high costs. The design simulation and combination parameter optimization of a miniaturized torque limiter for a specific model are focused on. Firstly, based on the principle and elements of the steel ball's inclined surface disengagement, some mathematical formulas are established and a three-dimensional structure is designed, identifying the key parameters affecting the performance of the torque limiter. Secondly, the torque transmission characteristics and structural strength of the torque limiter are simulated, and the accuracy of some strength simulation results is verified by using Hertz contact theory. Thirdly, the main structural parameters are optimized and evaluated by using the orthogonal experiment method, obtaining the best parameter combination. Finally, two principle prototypes are produced based on the models before and after optimization, and static disengagement experiments are conducted to verify the accuracy of the disengagement torque under static load.

As an important component of aviation control and power systems, the suction characteristics of DC electromagnetic coils used in aviation valves are a key factor in the design of electromagnetic coils. Taking the magnetic-proof ring magnet in the DC magnets for aviation valves as the research object, the magnetic-proof ring magnetis modeled in ANSYS Maxwell and the magnetic field distribution is given. The effects of different air gap, different parameters and armature length of the magnetic-proof ringon the suction characteristics of the electromagnet are analyzed. On this basis, two optimization methods are applied to the multi-objective design of the suction force at different positions of the electromagnet. One is to use the orthogonal test method to carry out the primary and secondary analysis of the factors that affect the suction force characteristics of the electromagnet more obviously. The other is to use the optimization software optislang to carry out the sensitivity analysis of the factors and the optimization design based on the evolutionary algorithm. Finally, a comparative analysis of the improvement effect of the two pairs of methods on the suction characteristics is carried out. The results show that optislang optimization is more in line with the requirements of electromagnet suction.

For the aerodynamic and overall optimization of hypersonic glide vehicles, this study proposes a performance evaluation method grounded in exergy theory. A multidisciplinary exergy dissipation model is developed, integrating aerodynamics, thermal protection, control, structures, and trajectory. This framework consolidates diverse metrics—such as aerodynamic efficiency, stability, and maneuverability—into a single, physically meaningful exergy loss parameter, enabling quantitative trade-off analysis. Using an HTV-2-like lifting-body configuration, aerodynamic optimization is performed with the objective of minimizing exergy loss, and its differences from lift-to-drag ratio optimization are examined. Based on the exergy balance equation, the potential applications of exergy loss analysis in conceptual design are discussed. The results indicate that this approach can rapidly identify performance bottlenecks, support multidisciplinary design optimization, and offer a new theoretical tool and evaluation paradigm for hypersonic vehicle design.

The gauging accuracy of propellant filling system is critical to the success of aerospace launch. Because of the defects of the calibration method for the flowmeter of launch site filling system, the deviation for the liquid level I value calculated by the filling system flowmeter and the theoretical value of the rocket tank liquid level I is quite large. An online calibration method is proposed for the flowmeter of filling system by which K coefficient of flowmeter is corrected by the rocket tank liquid level I. The result is shown that gauging accuracy of propellant filling system in launch site is enhanced, which is of great importance for the success of rocket launch.

The gas-liquid combined rapid erection hydraulic system is a new type of large flow hydraulic system which is driven by gas and motor pump, and can greatly increase the erection speed. The fault analysis and the reliability analysis of a rigid erecting hydraulic system with combined gas-liquid oil is carried out. Then the fault tree analysis is carried out by taking the fault of excessive vibration in the erection position as an example. The simulation analysis of typical faults of the system is carried out by means of co-simulation, and the relationship between fault causes and fault phenomena is studied and the effects and hazards of the fault are discovered. Some improvement measures are put forward to improve the reliability of the system.

To study the dynamic characteristics of the cantilever turbopump rotor in rocket engines, finite element models of the rotor dynamic characteristics are established using 3D solid elements and 2D beam elements to conduct dynamic characteristic analysis. The sensitivity of the impeller and turbine to unbalance on the rotor is obtained. High speed dynamic balance tests of the rotor are conducted on a high-speed rotating tester, and the results show that the finite element model well reflects the true dynamic characteristics of the rotor, with a calculation error of no more than 5%. Compared with 2D beam element model, the calculation accuracy of the 3D solid elements model is higher. The rotor is most sensitive to the imbalance on the turbine, providing a theoretical reference for high-speed dynamic balancing test. After high-speed dynamic balancing, the amplitude reduction of the rotor at critical speed is not less than 70.27%, and the reduction of elastic support stress is not less than 84.38%, indicating good dynamic balancing effect. The research provides a reference for the analysis of the dynamic characteristics of the rotor of a large cantilever turbopump and high-speed dynamic balancing tests.

In response to the application background of satellites passing over or observing a ground target within a specific time, the Walker constellation scheme design is carried out for meeting the revisiting time requirements. The models of a satellite coveraging a ground target are constructed. The methods for calculating the time-windows of a satellite passing over a ground target, and onboard circle/rectangular-field-of-view sensor observing a ground target are designed. On this basis, a Walker constellation scheme design algorithm which satisfies the revisiting time requirement with the minimum satellite number is developed. The simulations and analyses are provided for three simulation scenarios. The results of the developed algorithm are compared with STK, and the average error of revisiting times is less than 1.1 s, which verifies the accuracy and rationality of the models and the algorithm. The relevant research results can provide reference for the design of Earth observation constellation schemes.