Line Design Research Articles

Numerical investigation of cooling performance of 3D-printable cooling structure for aero-engine combustor

Thermal protection is an essential technology for gas turbine hot components to cope with the unprecedented thermal loads, and to ensure their enduring and efficient operation. A 3D-printable hybrid cooling cellular structure is suggested in this paper, the cooling property of which in a Can-type combustion chamber with chemical reaction considered is evaluated in detail. Reynolds Stress Turbulence Model together with the non-premixed combustion model are used to resolve the detailed flow structures and turbulence-chemistry interactions. Cases of cooling cellular with various film hole inclined angles are compared and analyzed. Results show that the cooling cellular can reduce the temperature of combustor liner noticeably, especially at the region near the second row of dilution holes. Meanwhile, the cooling performance is improved as the decrease of inclined angle, with an improvement of 29.1% as the inclined angle range from 90° to 30°, because the smaller incline angle is more resilient to coolant lift-off. A comparation with effusion cooling scheme is also made and concluded that the case of hybrid cooling exhibits a 673%-1409% higher porosity ratio, while the cooling effectiveness is reduced about 3.6%-8.3%. The lower performance of the hybrid cooling is explored further with a flat plate conjugate heat transfer numerical test, and ultimately attributed to the relative lower flow rate of coolant air induced by higher pressure loss of hybrid cooling cellular. Finally, the compound angle is further introduced into the hybrid cooling cellular. Results show that the impact of compound angle on cooling property depends highly on the angle between the film outflow and the swirling main-flow. The performance of compound angle cases will only increase when cooling cellular deflects in opposite directions of swirling flow, not vice versa. Overall, the hybrid cooling cellular shows a great potential in the cooling design of combustor liner. A smaller incline angle with compound angle deflected in the opposite direction of the swirling main-flow are also recommended for increased cooling performance.

Integer and constraint programming models for the straight and U-shaped assembly line balancing with hierarchical worker assignment problem

ABSTRACTThe solution to the assembly line balancing with the hierarchical worker assignment problem (ALBHWP) provides the optimal allocation of workers and tasks to the stations that minimise the total worker cost. In the ALBHWP, tasks differ in terms of the qualification requirements of workers, and the qualification levels of workers are hierarchical. In the hierarchical workforce structure, a lower qualified worker can be replaced by higher qualified ones with higher costs, while the vice versa is not applicable. This problem has only been studied for straight assembly lines so far. In this paper, we introduce the ALBHWP for U-shaped assembly lines. We developed integer and constraint programming models for solving the ALBHWP and compared their effectiveness using an extensive set of benchmark instances. We solved the ALBHWP for straight and U-shaped assembly lines comparatively. Constraint programming models have been statistically proven to provide better quality solutions faster than integer programming models. Besides, the CP model outperforms the only available metaheuristic in the literature for the S-ALBHWP in almost all problem sizes. Another observation is that a U-shaped line design is more cost-effective than a straight line design, but solving the ALBHWP for U-shaped lines is more difficult regarding computational complexity.

Research on Children's Educational Toy Design of Yueqing Fine Lines Engraved Paper in the Memetics Perspective

Exploring the application and integration of Yueqing Fine Lines Engraved Paper culture with the design of children's educational toys in the perspective of memetics, aiming to address the survival crisis faced by Yueqing Fine Lines Engraved Paper and achieve the inheritance and innovative development of culture. Based on memetics, cultural memes of Yueqing Fine Lines Engraved Paper are extracted, classified, deconstructed, and recombined for optimization. A design model for Yueqing Fine Lines Engraved Paper cultural products based on memetics is constructed, and the effectiveness of memetics in cultural product design is discussed through practical cases. This enriches the application of memetics and provides guiding insights for region-based cultural product design, promoting the inheritance and innovation of culture.

Theoretical algorithm for maximum jump height of the conductor after ice-shedding considering elevation angle and nonlinearity

The determination of maximum jump height of the conductor in ice zones is extremely important for the design of transmission line. Considering the elevation angle and nonlinearity, the theoretical formulas for maximum jump height of the conductor after ice-shedding is derived. Based on the catenary equation theory, simplified models of a single span horizontal and inclined conductors following ice-shedding are built using the same and different two suspension points respectively. Regarding ice-shedding of the conductor as a sudden loading, the energy conversion equation about the maximum jump height is established based on the energy method. Combined with the cable structure theory, the formulas for maximum jump height of the horizontal and inclined conductor are presented. Additionally, finite element method (FEM) was carried out with software Ansys on a single span horizontal and inclined conductor under different span length, initial stress and mass ratio ice-conductor.The accuracy of the presented formulas was verified by the results of maximum jump height for simulated conductors. Finally, error analysis is conducted considering the nonlinear change of dynamic tension. And some formulas are revised according to the reasons of errors.The calculated results of revised formulas match the FEM analysis results better, thus the accuracy of these formulas is improved. The given formulas establish the quantitative relationship between the maximum jump height and the sag of the conductor, maximum sag difference in midspan, the dimensionless frequency and the mass ration ice-conductor. The presented formulars for maximum jump height meet the engineering design requirement and provides theoretical guidance for conductor lines design.

Integrating Virtual Surgical Planning and 3D-Printed Tools with Iliac Bone Grafts for Orbital and Zygomatic Reconstruction in Hemifacial Microsomia Patients.

Hemifacial Microsomia (HFM) is the second most common congenital craniofacial malformation syndrome, and the complexity of HFM makes its treatment challenging. The present study aimed to introduce a new approach of utilization of virtual surgical planning (VSP) and 3D-printed surgical adjuncts for maxillofacial reconstruction. Five HFM patients were included in this study. All participants were provided with a full VSP, including the design of osteotomy lines, the design and fabrication of 3D-printed cutting guides, fixation plates, and titanium mesh for implantation. With the assistance of 3D-printed cutting guides and fixation plates, the orbital deformities were corrected, and a 3D-printed titanium mesh combined with iliac cancellous bone graft was applied to reconstruct the zygomatic arch. The surgical accuracy, effectiveness, and bone absorption rate were evaluated. All patients completed the entirely digital treatment process without experiencing severe complications. The surgical adjuncts were effective in aligning the movement of the bone segments with the surgical plan, resulting in mean 3D deviations (1.0681 ± 0.15 mm) and maximum 3D deviations (3.1127 ± 0.44 mm). The image fusion results showed that the patients' postoperative position of the maxilla, zygoma, and orbital rim was consistent with the virtual surgical plan, with only a slight increase in the area of bone grafting. The postoperative measurements showed significant improvement in the asymmetry indices of Er (AI of Er: from 17.91 ± 3.732 to 5.427 ± 1.389 mm, p = 0.0001) and FZ (AI of FZ: from 7.581 ± 1.435 to 4.070 ± 1.028 mm, p = 0.0009) points. In addition, the observed bone resorption rate at the 6-month follow-up across the five patients was 45.24% ± 3.13%. In conclusion, the application of VSP and 3D-printed surgical adjuncts demonstrates significant value in enhancing the precision and effectiveness of surgical treatments for HFM. A 3D-printed titanium mesh combined with iliac cancellous bone graft can be considered an ideal alternative for the reconstruction of the zygomatic arch.

Design and Motion Simulation of Conveyor Production Line for Salted Kelp Turnover Box

Design and Motion Simulation of Conveyor Production Line for Salted Kelp Turnover Box

Actual and design wind loads for overhead transmission lines in the Central European part of Russia

This paper reveals an impact of the climatic loads on the sustainable operation of power grid facilities. An overview is provided considering various international standards related to the design of overhead transmission lines. The aim of the research was to analyze and compare the actual and design values of wind loads for transmission lines located in the Central European part of Russia and operated by the power grid company “Rosseti Center and Volga Region”. An analysis of wind load dynamics has been carried out considering the territory of 9 subjects of Russia and 1983-2022 timeframe. The actual climate data were computed according to the direct measurements of the weather stations. Nomograms of the maximum annual wind speeds are formed utilizing the first limiting Gumbel distribution for two climatic regions of the research area. The retrospective wind loads values were compared against the design values. The results of the study show that climate standards should be updated more frequently as it is the case nowadays, in particular, it relates to revision of existing wind loads or recalculation of wind speed correction factors for the near future.

A design method of volute profile of multi-blade centrifugal fan based on DRBF model

The forward-curved multi-blade centrifugal fan is widely used in the ventilation and household appliance industries with limited space due to its small size factor, high pressure coefficient, and large outlet flow coefficient. Conventional centrifugal fan structural designs rely on empirical data, resulting in drawbacks during usage such as low airflow velocity, high noise levels, and high energy consumption. In order to optimize fan structure, enhance aerodynamic performance, and seek new, effective approaches for energy efficiency and emissions reduction, this paper focuses on a combined design method that integrates scroll line design with aerodynamic performance and noise control. The goal is to propose a noise prediction and analysis method for multi-blade centrifugal fans, addressing the design contradiction between optimal fan functionality and minimal noise within limited design dimensions. The dynamic radial basis function method is introduced to investigate the geometric parameters of the scroll line, utilizing coherence analysis to identify the reasons for insufficient aerodynamic performance and noise reduction measures. Through the research, it is found that unreasonable design leads to a large turbulent vortex region within the blade passage and internal flow field, particularly involving circulation and backflow, which significantly reduces the fan's aerodynamic performance and operational efficiency. The design incorporates a composite scroll with a logarithmic spiral and circular arc integrated into one, and algorithm-based optimization of the scroll tongue, facilitating the transition of turbulence at the scroll outlet and the gap between the scroll tongue and impeller. Numerical results show an increase in airflow of 3.04 m3/min and a noise reduction of 3.79%. This indicates that the composite scroll design with a logarithmic spiral plays a dominant role in accelerating the aerodynamic performance of the scroll and reducing noise radiation.

New technological techniques for local repair of worn sections of the converter lining

The duration of converter campaigns has increased significantly due to improvements in steel smelting technology, quality of used refractories, lining design, as well as due to various ways of maintaining the lining in working condition during the campaign (hot repair).

Model-Driven Multibeam Line Measurement System Design

Multibeam bathymetric system is a complex combination of multi-sensor system. The multibeam bathymetric system is mainly used in the measurement of water depth of waterways, and the scientific layout of the survey line can improve the measurement efficiency, and at the same time, truly and perfectly reflect the topography of the waterway. This paper establishes a mathematical model of coverage width and overlap rate between adjacent strips for multibeam bathymetry, and calculates the parameters such as water depth, coverage width and overlap rate between adjacent strips at the center point of different survey lines. Firstly, a single slope multibeam line model was established to calculate the coverage width and the overlap rate between adjacent strips of the multibeam bathymetric system, taking into account the influence of the slope of a single slope. Then, considering the influence of the angle between the direction of the survey line and the projection of the normal direction of the seafloor slope on the horizontal plane, a mathematical model of multibeam bathymetry with variable survey line direction is established by downscaling the geometrical relationship in the three-dimensional space to the two-dimensional plane. Again, based on the principle of line design, all the lines with overlap rate between 10% and 20% are comprehensively screened, and the enumeration method is adopted to find out the optimal lines under each group of conditions. Finally, a three-dimensional seabed model is constructed based on the actual sea depth data, and the optimal measurement direction and spacing of the survey lines are determined based on the real seabed topographic features, which achieves the goal of minimizing the length of the survey lines, and at the same time, ensures that the survey lines can cover the entire sea area to be surveyed, and the iterative method is used to search for the final direction of the survey lines and find the optimal solution.

Numerical and Experimental Investigation of Time-Domain-Reflectometry-Based Sensors for Foreign Object Detection in Wireless Power Transfer Systems

Foreign object detection (FOD) is considered a key method for detecting objects in the air gap of a wireless charging system that could pose a risk due to strong inductive heating. This paper describes a novel method for the detection of metallic objects utilizing the principle of electric time domain reflectometry. Through an analytical, numerical and experimental investigation, two key parameters for the design of transmission lines are identified and investigated with respect to the specific constraints of inductive power transfer. For this purpose, a transient electromagnetic simulation model is established to obtain and compare the sensor impedance and reflection coefficients with experimental data. The measurement setup is based on parametrically designed sensors in laboratory scale, using an EUR 2 coin as an exemplary test object. Consequently, the proposed simulation model has been successfully validated in this study, providing a comprehensive quantitative and qualitative analysis of the major transmission line design parameters for such applications.

Study on Wind-Induced Response and Wind Deflection Control of Overhead Sealing Net Structure Spanning Transmission Lines

Sealing net structures are frequently used as protective devices for newly constructed transmission lines that intersect existing lines. They aim to ensure safety during the construction and operation of the intersecting lines. To explore the wind deflection response characteristics of sealing net structures under wind loads, a model of the sealing net structure was created using ANSYS/APDL software for finite element analysis. This model represents an overhead sealing net structure spanning an existing line. The results obtained from finite element simulations aligned well with the theoretical calculations, indicating the validity of the established finite element model for accurately analyzing the wind-induced response of the sealing net structure. Expanding on this foundation, the study analyzed the impact of various factors on the wind deflection of the sealing net. These factors encompass the span, wind speed, pretension of the catenary cable, wind direction angle, arrangement angle, and method of additional stay cables. The research investigated the influence of these factors on the wind deflection of the sealing net structure. Additionally, a proposal was presented for arranging the closure structure to mitigate wind deflection. This proposal provides valuable guidance for the design and safety considerations of transmission lines and sealing net structures.

A Semi-Analytical Model of Contaminant Transport in Barrier Systems with Arbitrary Numbers of Layers

In regions with sanitary landfills, unsuitable liner designs can result in significant soil and groundwater contamination, leading to substantial environmental remediation costs. Addressing this challenge, we propose a semi-analytical model for solute transport that uses the advection–dispersion–reaction equation in a multi-layered liner system. A distinctive feature of our model is its ability to account for infiltration velocity, arbitrary numbers of layers, thin layers such as geomembranes, and mass flow. We validated our model against existing published models and applied it to a case study of a real sanitary landfill in the capital of Brazil. Through parametric analyses, we simulated contaminant transport across various layers, including the geomembrane (GM), geosynthetic clay liner (GCL), soil liner (SL), and compacted clay liner (CCL). The analyses showed the importance of choosing the most appropriate construction system based on the location and availability of materials. Considering toluene contamination, a GM molecular diffusion coefficient (DGM) greater than 10−13 m2 s−1 exhibited similar efficiency when compared with CCL (60 cm thick). In addition, the results showed that the liner system may have the same efficiency in changing SL (60 cm thick) for a GCL (1 cm thick).

A formula for hydrostatic pressure calculation in high-pressure railway tunnels

High hydrostatic pressure can cause common problems such as cracking and leakage in the lining of railway tunnels during operation. A clear understanding of the magnitude and distribution characteristics of hydrostatic pressure in tunnel lining under high-pressure conditions is crucial for optimizing the structural design of tunnel lining. In this study, professional equipment was first selected to measure the lining water pressure of two typical sections of Tunnel A on site, and the pressure distribution characteristics were analyzed; Then, a calculation model of the tunnel under high hydrostatic pressure was established using FLAC3D numerical calculation software. Select several calculation parameters and within a reasonable range of values, select multiple values for each parameter instead of just taking one value to form 60 working conditions, and calculate the corresponding tunnel lining water pressure for each working condition. Analyze the correlation between static water pressure and calculation parameters under various working conditions, propose a preliminary calculation formula for tunnel lining static water pressure, and finally use SPSS statistical calculation software to fit the final calculation formula for lining water pressure. This formula is applicable to the calculation of lining hydrostatic pressure under various parameters and is a universal calculation formula for tunnel lining hydrostatic pressure. Our proposed formula is very consistent with on-site measured data under similar geology conditions, providing a new method for calculating the hydrostatic pressure of tunnel lining.

Lined Up? Examining a “Waiting Line” Effect in Technology-Enabled Restaurant Menu Ordering

This research examines the impact of a waiting line on menu ordering behavior when interacting with self-service technology (SST), along with the underlying mechanisms and an intervention strategy drawing on attribution theory. We conducted three experimental studies to simulate a real-life event of menu ordering in a quick-service or fast-casual restaurant. According to the results, the presence of a waiting line can lead to time-pressured menu ordering behavior, especially when interacting with SSTs (vs. human staff). Further, we verified that customers’ perceptions of responsibility for service outcomes explain this SST-conditioned effect. Our findings also suggest a line design strategy that can mitigate the negative consequences of the “waiting line” effect in SST-enabled menu ordering. This research provides valuable insights into the unintended consequences of waiting lines and offers practical strategies for minimizing negative outcomes associated with SST-mediated services.

Methodology for Designing a System of Public Passenger Transport in a Functional Region

Transport, as an object of research and design, is directly influenced by other functional components of the territory, it is caused by them, but at the same time it determines them in terms of limitations and development. A comprehensive approach to the design of transport systems involves a wide range of analytical and synthetic activities. Transport and territory are interrelated, while transport is one of the main factors defining the functionality of territorial structures. The development of transport systems brings greater availability of work, services, and leisure activities. The transport solution in the territory must be directed towards the adequate satisfaction of the transport needs, which are characterized by the intensity of the transport relations in the territory, depending on the time and quality of the relocation. The article presents a methodology for the design of regional public passenger transport lines, in accordance with the principles of sustainable mobility, supporting the competitiveness of public passenger transport and the efficient use of resources. The proposed methodology presupposes an already completed and processed analytical phase of the transport planning process and includes the impact of public passenger transport on the external environment. The methodology is applicable under the conditions of designing a completely new transport service system, as well as in the process of reorganizing existing transport systems, including rail and bus transport.

Measuring route diversity in spatial and spatial-temporal public transport networks

Route diversity is a pivotal metric for evaluating the redundancy of transportation networks, a fundamental aspect of system resilience. This study provides a comprehensive exploration of route diversity in multimodal public transport systems, specifically considering the unique characteristics of bus networks. Our research introduces a two-pronged approach to measuring route diversity within spatial public transport networks, delving into service-based and infrastructure-based perspectives. The former assesses redundancy against transit service disruptions by factoring in transit line overlaps, while the latter evaluates redundancy against infrastructure-related interruptions by considering overlapping road segments on which transit lines rely. In addition, the study advances by modelling public transport systems as multilayer spatial-temporal networks, integrating time-variable service frequency and travel time uncertainty, which enables us to derive route diversity for origin-destination (O-D) pairs across different time periods.We present a case study of the multimodal public transport network in Jiading District, Shanghai, revealing a power-law distribution of the route diversity. The results unveil O-D pairs with lower route diversity, underscoring their lack of resilience against various disturbances. Lower service-based route diversity suggests the necessity of enhancing service frequency and bolstering cross-line combined transit scheduling, while lower infrastructure-based route diversity could warrant the design of road-diversified transit lines, especially within bus corridors. Besides, relative route diversity between the two indices highlights specific O-D pairs with notable disparities in service and infrastructure redundancy. This difference is correlated with the distance between O-D pairs and the road network's configuration. This analysis underscores the method's potential to offer more relevant insights to public transport planners and operators for adjusting transit lines and schedules through a resilience-focused lens.

Optimal product line design strategy for green and non-green products with blockchain technology

Optimal product line design strategy for green and non-green products with blockchain technology

Influence of the Approach to Membrane Mass Transfer Characteristics Determination on the Process Simulation Results

In this work, the dependence of the output characteristics determined in the simulation of the gas separation membrane process on the gas transport characteristics of the membrane specified as parameters of the membrane module model has been investigated. The study was carried out on a laboratory setup containing polyphenylene oxide hollow fibres. As a result of this integrated study, including theoretical and experimental approaches, it has been determined that when using the ideal gas transport characteristics obtained for pure gases to simulate the process, the error expressed in achievable concentration of the target component in the product stream ranges from 1.5 to 8.8% compared to the experimentally obtained values for the same module geometry and the same membrane area. This discrepancy can lead both to unattainable targets for the technological line and to an incorrect technical and economic evaluation of the process. Thus, the design of technological lines using mathematical modelling tools should be based on the “effective” gas transport characteristics of the material and/or product obtained for the components of real gas mixtures or simulating real gas mixtures.

Design of T-shaped non-uniform microstrip lines for reducing crosstalk in high-speed PCBs

High-speed and high-density PCB circuit layout design faces serious signal integrity problems. Crosstalk is one of the key problems affecting signal quality. Periodic non-uniform differential microstrip lines have the possibility of reducing crosstalk. This paper proposes a T-shaped non-uniform microstrip line, which adds the T-shaped bump on the inner side of the parallel microstrip lines. The microstrip line adopts the minimum batch production process linewidth to maintain high density, which is suitable for occasions where the line spacing is three times the linewidth. The principle of crosstalk mitigation for T-shaped microstrip lines is explained, and the evolution process of T-shaped microstrip lines is given, compared with parallel microstrip lines and tabbed lines with the same density. The simulation resulting in the time domain and frequency domain shows that the transmission performance of the T-shaped microstrip line is good, and crosstalk can be effectively suppressed in a high-frequency band, even better in some specific frequencies due to the crosstalk fluctuation with frequency.