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  • 2020 Volume 37 Issue 5
    Published: 25 October 2020
      
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  • Influence of Structural Parameters on the Atomization Characteristics of Air-assisted Atomizer
    2020, 37(5): 1-9.
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    In order to obtain the influence of the nozzle structure parameters on the atomization characteristics of the pneumatic atomizer, the atomization characteristics of the pneumatic atomizer were studied by the combination of experimental test and numerical calculation. The SMD and spray cone angle of the nozzle under different fuel pressure and atomized air pressure were tested. VOF model is used to simulate the effect of gas-liquid two-phase flow and nozzle structure parameters on atomization characteristics. The results show that the influence of fuel pressure difference on atomization characteristics is not obvious, and the influence of atomization air pressure on atomization characteristics is obvious under low fuel pressure difference; because of the existence of center negative pressure in the swirl chamber, air will be sucked into the swirl chamber to form air core with strong turbulence; the influence of different structural parameters on atomization parameters is different, and the influence of nozzle diameter D1 on flow coefficient The maximum angle of the horn angle has the greatest influence on the thickness of the liquid film, and the inclination angle of the swirling plate has the greatest influence on the spray cone angle. In order to achieve satisfactory fuel atomization quality, the structural parameters of the nozzle should be optimized.
  • Research on the application of Floyd algorithm in track planning of aircraft under multiple constraints
    2020, 37(5): 10-15.
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    Abstract：This paper studies the practical engineering application of Floyd algorithm in the rapid track planning of aircraft under multiple constraints. Firstly, a path model suitable for engineering application is established based on various constraints such as flight distance and positioning and calibration error. And using Floyd algorithm to solve the problem, find the shortest path of the aircraft to reach the mission point. Finally, the feasibility of the scheme is verified by MATLAB simulation. Compared with A* algorithm and the minimum deviation search algorithm, the results show that Floyd algorithm has the best results.
  • Research on the Estimated Method of the Take-off Weight of the Electric Light Sport Aircraft
    2020, 37(5): 16-23.
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    Electric aircraft has the characteristics of zero pollution, low noise, etc. It doesn’t have any negative impacts on the environment. It represents one of the important directions of the research and development of aviation industry. Take-off weight is one of the important parameters of the aircraft, which directly serves the general layout, performance, load, features, and cost estimation, etc. Take-off weight estimation is not only a key part in the design process, but also one of the important work in the aircraft conceptual design. Because the weight of the electric aircraft remains unchanged in the flight, the method of parameters determination is different from the traditional fuel aircraft. According to characteristics of the electric power system and the battery, and the relevant design requirements of electric aircraft, the weight estimation methods of the electric power system and the battery were presented. Based on the related design parameters of electric aircraft in the conceptual design, and the each parts weight estimation formulas of electric aircraft, the weight estimation model of electric aircraft was established. A convergence value was obtained through iterative calculation, which was the take-off weight estimation value of electric aircraft. When the convergence value was putted in the each parts weight estimation formulas, the each parts weight estimation values would be obtained. Using an electric light sport aircraft as an example, the effectiveness of the method was verified.
  • Design and Optimization of Support Frame Structure of Battery Warehouse for a Type of Electric Aircraft
    2020, 37(5): 24-34.
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    Lightweight design of electric aircraft can increase the payload or extend the flying range of electric aircraft. In this paper, the battery compartment support frame structure of electric aircraft is selected as the research object. By the use of HyperWorks, the process of optimization of the battery compartment support frame structure are performed separately with structural topological optimization, modal analysis, and topology for Isotropic material. In addition, optimization and lay-up optimization of composite laminates, and static analysis of each optimized model are validated. Therefore, the lightweight and optimization design of the battery compartment support frame are realized.
  • Study on structural stress analysis of two-valve valve based on Hyperworks
    li jingwu
    2020, 37(5): 35-41.
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    In the system, two valve group measuring appliance valve composes the part importantly, therefore must carry on the detailed crustal stress analysis and the evaluation to it.Article synthesis finite element analysis software Hyperworks carries on the finite element computation analysis to two valve group measuring appliance valve, including two valve group measuring appliance valve whole and the valve chest, the valve petal, the valve lever, the valve cover important components intensity analysis.The article main analysis content contains three parts: The first part has mainly completed two valve group measuring appliance valve under design operating mode stress analysis and the modality analysis; The second part has mainly completed two valve group measuring appliance valve under impact load stress analysis; The third part has mainly completed two valve group measuring appliance valve under earthquake load stress analysis.Carried on the confirmation to the valve class components structural strength to provide the advantageous research foundation.
  • Research of simulation analysis and component test of the enlighten aluminum alloy wheel
    2020, 37(5): 42-45.
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    In the process of automobile design, how to realize the lightweight of important parts of chassis is the key to the success of the design, especially for the wheel, steering knuckle, brake disc, brake clamp and hub shaft which have a great impact on the sprung mass. In the paper, considering three aspects of the enlighten structure design, enlighten material application and new mechanical technology, structure improvement to achieving the enlighten wheel has been researched. In the developing process of the wheel, the CAE simulation analysis method has been applied to research the wheel impact analysis, dynamic bending and radial direction fatigue analysis. And then the wheel impact test, dynamic bending fatigue test and radial direction fatigue test have been carried out to verifying the wheel reliability. By means of earlier stage of the enlighten structure design, simulation analysis and later stage of the component test verification, Finally, the feasibility of the technical route is verified and the requirement of wheel weight reduction is realized.
  • The effects of laser cladding parameters on the microstructure and properties of cladding layer of (TiC+B4C)/Co-based alloy on the surface of ductile iron
    2020, 37(5): 46-54.
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    Abstract：In this paper, the cladding layer of Co-based alloy with 50wt.% (TiC+B4C) is prepared on the surface of QT600-3 ductile iron by the laser cladding method and the effects of the optical fibre laser parameters on the microstructure, the second phases and hardness of the cladding layer are investigated. The results show that the dendrite arm space increases and then decreases with the increase of laser power at a given scanning speed of laser. With increasing laser power, the particle sizes of both TiC and clustered B4C decrease with the more uniform distribution, which the TiC morphology changes from irregular block to petaloid shape. At a given laser power, the dendrite arm space decreases, but the average sizes of the clustered B4C and TiC particles increases with an uneven distribution with the increase of the laser scanning speed, which the petaloid morphology of TiC is transformed into irregular polygon shape. The maximal average hardness of laser cladding layer is reached to 1379.28 HV0.2, 5.9-fold of that of ductile iron matrix, when the laser power is 1.2kW and the scanning speed of laser 4mm/s.
  • Research on ciphertext search based on quantum homomorphic encryption
    2020, 37(5): 55-62.
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    This paper proposes a new ciphertext search scheme in the quantum environment. For the existing quantum homomorphic encryption scheme, the key update process of the T-gate is too tedious so that a new trusted server-assisted processing of the T-gate scheme is present in this paper. Based on this scheme, a ciphertext search scheme is proposed. In this scheme, the server is divided into a trusted server and a semi-trusted server. The semi-trusted server completes the search operation. When a T-gate exists in the circuit, the quantum state is uploaded to the trusted server and the trusted new server decrypts it. After performing the T-gate operation, the encryption key is randomly generated and uploaded to the semi-trusted server. The trusted server helps the client to complete the key update operation, which reduces the pressure on the client. Based on this scheme, a ciphertext search experiment in the binary case on the IBM quantum simulator is given. The experimental results show the efficacy of our scheme.
  • Research on Multiple Paths of Performance Improvement in Civil Aviation Enterprises——A Fuzzy-set Qualitative Comparative Analysis
    2020, 37(5): 63-71.
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    With the rapid development of civil aviation industry, the competition among airlines is gradually intensifying. Performance management has become an important means to enhance market competitiveness. In this paper, 12 domestic and foreign listed airlines are taken as the research object, and the qualitative comparative analysis method of fuzzy-set (fsQCA) is applied to explore the path selection and preconditions of performance improvement of civil aviation enterprises, and to analyze the interaction of enterprise scale, operational efficiency, service quality, management structure and other factors. The research finds that the configuration of high passenger rate and low passenger complaint rate, as well as the configuration of large-scale enterprises and more female executives can bring about higher performance. In large-scale airlines, the operation efficiency and service quality of enterprises have substitution effect, but there are only two configurations that lead to low enterprise performance. This paper examines the impact of conditional configuration rather than a single variable on corporate performance, and concludes different paths leading to high and low performance, showing multiple conjunctural causation between the level of corporate performance and its influencing factors, and the causal asymmetry is verified.
  • Research on the Progress and Trend of Green Building Supply Chain Management Based on CiteSpace Software
    2020, 37(5): 72-79.
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    To study the current state of the green building supply chain, Taking the relevant literature in the field of green building supply chain in WOS database from 1999 to 2019 as the research object, the knowledge structure and hot spot evolution knowledge graph of green building supply chain research are drawn by CiteSpace software. It is found that the knowledge structure of green building supply chain mainly focuses on the evaluation of energy efficiency and carbon emission reduction, the analysis of driving factors of building energy conservation and emission reduction, and the design of policy mechanism. at the same time, it is concluded that the evolution analysis path of research hotspots is: concept formation and theoretical construction-macro energy saving and emission reduction driving research-policy evaluation and industry analysis. Finally, the green building supply is put forward. The future development trend of the chain research lies in taking into account the humanistic concept, the design and evaluation mechanism and the construction of innovation system. It is of great academic significance to analyze the development trend of green building supply chain and promote the in-depth study of green building supply chain.
  • Research on the relationship between stock liquidity and capital cost based on the dynamic adjustment of capital structure
    2020, 37(5): 80-89.
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    Different capital structure, dynamic adjustment speed of capital structure and stock liquidity level of listed companies will affect the financing cost of external financing. Based on this, this paper empirically tests the impact of stock liquidity on the cost of equity capital, the cost of debt capital and the cost of weighted capital of listed companies by taking A-share listed companies in Shenzhen and Shanghai in 2009-2018 as the research sample; in order to further explore the impact of capital structure adjustment of listed companies, the dynamic adjustment of capital structure is added to adjust the dynamic adjustment of capital structure The influence of integral velocity on the above relationship is further examined. The empirical results show that the better the stock liquidity is, the smaller the cost of equity capital, debt capital and weighted capital are, and there is a significant negative correlation between them; while the speed of dynamic adjustment of capital structure of listed companies can effectively adjust the negative correlation, and the faster the speed of dynamic adjustment of capital structure, the stock flow of listed companies is The more significant the negative effects of mobility on the cost of equity capital, debt capital and weighted capital are.
  • Single-machine group scheduling with common due-window assignment
    2020, 37(5): 90-96.
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