Design Point Research Articles

On the performance of highly aggressive inter compressor ducts

Abstract The enhancement of jet engine components may result in the expansion of the established design space. In particular, the trend towards short and therefore highly aggressive inter compressor ducts (ICD) extends the traditional design space. The potential for fuel savings resulting from a reduction in engine weight is in contrast to the emergence of a more complex flow field. Many studies consider the secondary flow system of highly aggressive ICDs at the design point, but there is a lack of off-design considerations. To fill this gap, the present study investigates in detail the off-design performance of the new German Aerospace Center (DLR) test case. Firstly, computational fluid dynamics (CFD) simulations of different typical operating points allow detailed considerations of the flow field under off-design conditions. Secondly, a variation of the inlet conditions describes the sensitivity of highly aggressive ICDs to different low-pressure compressor operating points. Finally, the comparison of the CFD stagnation pressure loss with the loss predicted by a preliminary off-design method validates the use of traditional off-design prediction during the preliminary design of highly aggressive ICDs.

Field Monitoring and Analysis of Factors Influencing Existing Tunnels Laterally Adjacent to Foundation Pit Excavations

To investigate the factors influencing existing tunnels adjacent to foundation pit excavations, this paper focuses on a case of excavation of MTR station foundation pits near an existing tunnel. Monitoring data are collected and analyzed, and a two-dimensional numerical model of the pit–tunnel system is established using ABAQUS (2022) software. This study examines the effect of excavation factors on the tunnel, including excavation depth, horizontal spacing between pit and tunnel, support pile wall dimensions, support structure insertion ratio, horizontal support stiffness, and geological conditions. The research results indicate that for tunnels in silty clay formations, the depth of pit excavation should be limited to 20 m. When the horizontal spacing between a foundation pit and tunnel in a silty clay formation is within 1.5 times the depth of excavation, the tunnel is more significantly affected by tunnel excavation works in the adjacent pits. Increasing the horizontal support stiffness has the greatest effect on controlling deformation and stress in the tunnel structure. The degree of influence on deformation and stress in the tunnel due to laterally adjacent excavation of a foundation pit varies with geological conditions. Among them, tunnels in muddy-silty clay and silty soils are the most affected, and it is recommended that reinforcement measures be optimized and monitoring be strengthened. The conclusions of the present study can provide a reference point and guidance for the optimal design of similar pit projects.

Visual target tracking based on fractional – order bidirectional hybrid attentional feature fusion

This paper mainly designs and implements target tracking based on fractional – order feature fusion to solve tracking drift and tracking box jumping in complex scenes. Firstly, the starting point and overall structure of the model design were introduced. Secondly, in response to the low information utilization of the feature extraction network in the target tracking framework at the local scale of the target, a fractional – order node function based attention CNN hybrid attention extraction module was proposed to improve the robustness of target tracking. Finally, overall performance was quantitatively and qualitatively evaluated on multiple evaluation datasets with various advanced trackers. The results showed that the algorithm proposed in this paper had a high tracking advantage under severe changes in scale morphology, dynamic blurring, and similar interference attributes.

Estimation of Areal Reduction Factors in South Africa, Part 2: Application and validation at catchment level

Various empirical methods have evolved over the years in South Africa to estimate either design floods, design rainfall, catchment response time, and/or Areal Reduction Factors (ARFs). The verification of any empirical method requires the use of observed data not used during the calibration process, while observed data is also required for validation purposes. In the case of ARFs, which are used to convert average design point rainfall depths to an areal (catchment) design rainfall depth, all the calibration/verification data sets remain only estimated sample values of design rainfall. Subsequently, this paper presents an independent application and validation of the regional geographically-centred ARF method (Pietersen 2023) against the currently recommended geographically-centred ARF method (Alexander 2001) by incorporating the different ARF estimates into the Rational Method (RM) to highlight the impact thereof on the resulting flood estimates. In applying a ranking-based goodness-of-fit selection procedure, the RM in combination with the newly derived regional geographically-centred ARF method (Pietersen 2023) resulted in the best deterministic flood estimates when compared to the at-site statistical flood peaks. Apart from the ARFs, catchment response time, design rainfall, and weighted runoff coefficients are all regarded as key input parameters for design flood estimation in ungauged catchments.

Comprehensive Thermodynamic Performance Evaluation of a Novel Dual-Shaft Solid Oxide Fuel Cell Hybrid Propulsion System

With the rapid growth of air travel, reducing carbon emissions in aviation is imperative. Electric aircraft play a key role in achieving sustainable aviation, especially for large civil aircraft, where reducing emissions, improving the fuel efficiency, and enabling flexible power regulation are essential. This study proposes a dual-shaft, separated-exhaust fuel cell hybrid aircraft propulsion system (HAPS), using a solid oxide fuel cell (SOFC) to replace the conventional turbine-driven compressor. The independent speed control of the high- and low-pressure spools is realized via a power distribution system. A thermodynamic model is developed, and performance evaluations, including parametric, exergy, and sensitivity analyses, are conducted. At the design point, the system delivers 36.304 kN thrust, 16.775 g/(kN·s) specific fuel consumption, 15.931 MW SOFC power, and 54.759% SOFC efficiency. The exergy analysis highlights the optimization of components like the heat exchanger and fan to reduce energy losses. The sensitivity analysis reveals that the spool speeds and fuel utilization significantly impact the performance. The findings provide valuable insights into optimizing control strategies and offer a novel, efficient, and low-carbon power solution for aviation, supporting the industry’s transition towards sustainability.

Development of a Reduced Order Model-Based Workflow for Integrating Computer-Aided Design Editors with Aerodynamics in a Virtual Reality Dashboard: Open Parametric Aircraft Model-1 Testcase

In this paper, a workflow for creating advanced aerodynamics design dashboards is proposed. A CAD modeler is directly linked to the CFD simulation results so that the designer can explore in real time, assisted by virtual reality (VR), how shape parameters affect the aerodynamics and choose the optimal combination to optimize performance. In this way, the time required for the conception of a new component can be drastically reduced because, even at the preliminary stage, the designer has all the necessary information to make more thoughtful choices. Thus, this work sets a highly ambitious and innovative goal: to create a smart design dashboard where every shape parameter is directly and in real-time linked to the results of the high-fidelity analyses. The OPAM (Open Parametric Aircraft Model), a simplified model of the Boeing 787, was considered as a case study. CAD parameterization and mesh morphing were combined to generate the design points (DPs), while Reduced Order Models (ROMs) were developed to link the results of the CFD analyses to the chosen parameterization. The ROMs were exported as FMUs (Functional Mockup Units) to be easily managed in any environment. Finally, a VR design dashboard was created in the Unity environment, enabling the interaction with the geometric model in order to observe in a fully immersive and intuitive environment how each shape parameter affects the physics involved. The MetaQuest 3 headset has been selected for these tests. Thus, the use of VR for a design platform represents another innovative aspect of this work.

실제 맥락에서의 학습전이에 관한 민속방법론적 연구: 미디어 리터러시 수업 사례 분석

Objectives This study aims to understand learning experiences in real contexts as a core learning science inquiry topic regarding embodiment and transfer in learning. Methods This study relied on ethnomethodology (EM) as a learning science research method on learning experiences in real contexts. EM opened up the possibility of systematic observation and analysis of embodied experiences and situated learning through qualitative analysis of the composition of real-time situational contexts created by the interaction between agents and practical reasoning and behavior, thereby providing an important research methodology for learning science. EM played an important role in exploring how learners’ internal understanding of concepts they encounter is expressed and changed in the process of embodiment, that is, interaction. The subject of analysis in this study was a 16-hour media literacy class conducted at the graduate school of H University. Results First, transfer in learning has a dynamic characteristic that continuously appears throughout the learning process. Second, transfer appears in the process of interacting with various factors and recognizing situations to utilize knowledge. Third, transfer is not simply applying knowledge, but is achieved through the process of reconstructing and deeply understanding knowledge in various situations. Conclusions Transfer in learning is created in the process of integrating knowledge through continuous interaction between participants. In other words, transfer is created in the process of the flow of situational context, which is the interaction with various factors experienced to utilize knowledge. The teaching strategy that promotes transfer can be viewed as a role that maximizes the room for learners to choose their own judgment and actions by opening a space for participation where they can use all the resources that they can take in their own context, including the knowledge. In future research on the design of learning experiences, it is necessary to pay attention to the dynamic conditions and settings of the flow of micro-contexts created by the situational inference and actions revealed by the interaction between agents, which are important key points of learning design.

Gaussian Process-Based Robust Optimization with Symmetry Modeling and Variable Selection

Gaussian process (GP)-based robust optimization is an effective tool in product quality improvement. However, most existing variable selection methods are designed for parametric models and are unsuitable for nonparametric GP models. Additionally, improving the prediction accuracy of GP models with limited design points remains a significant challenge in robust optimization. To address these issues, this article proposes a GP-based multi-stage robust parameter optimization method that integrates symmetry modeling, sensitivity analysis (SA), and Markov Chain Monte Carlo (MCMC) techniques. First, a modified expected improvement (EI) criterion is introduced to enhance the utilization efficiency of design points. Second, a nonparametric variable selection technique based on SA is developed for GP models to identify significant variables. This method considers both independent variables and their interactions, improving the interpretability of GP models. Finally, the selected variables are used to construct the robust optimization model, and the genetic algorithm (GA) is employed to search for the optimal solution within the feasible domain. Numerical simulations and real-world experiments demonstrate the effectiveness of the proposed method. Comparative results indicate that the proposed method obtains more robust optimal input parameter settings compared to existing approaches.

An Enhanced Jig-Shape Approach to Lifting Propeller Design

The jig-shape approach decouples the design process of aeroelastic structures. During structural sizing, elastic deformations are subtracted from the initial shape to achieve a desirable flying shape under loads at one specific design point. However, due to nonlinear loads, stiffness, and deformations, there is a disparity between intended rigid and actual elastic propeller performance at off-design points. Propellers lifting air taxis or large cargo drones are particularly susceptible to such variances due to their slender design. This paper presents an enhanced jig-shape approach to minimize these discrepancies by inducing additional coupling effects counteracting elastic deformations. Beyond the traditional single-point predeflection analysis, the improved strategy employs geometric and structural modifications to mitigate errors at off-design points. Comparing the aeroelastic performance of propellers sized according to the traditional and the enhanced procedure illustrates the effectiveness of the modifications. The enhanced approach remains computationally efficient due to its decoupled nature. A novel finite beam element that accurately captures the relevant structural coupling effects of lifting propellers is derived. Applying unbalanced ply layups inducing extension–twist coupling is limited in effectiveness and increases weight. Modifying the coning angle of a straight blade affects loads and stresses but does not allow the adjustment of aeroelastic performance. Combining the coning angle with a swept planform enables the flexible correction of aeroelastic performance within limits at minimal weight increase.

Application of creative ideation practices using the example of school storage system design

The article presents the results of the practical application of ideation methods in the search for design solutions for the storage of school supplies, inventory and personal belongings of students. Current ideation techniques used in design are analyzed. A series of ideas found using methods such as Mental Map, Synectics, SCAMPER, Bionics, Focal Object Method, and Morphological Box are graphically presented. The progress of work on the design project to create a universal modular school storage system is illustrated as a continuation of a previously conducted analysis of modern school spatial environments and storage systems. Various options of storage modules assembly in a school environment are presented. The work is interesting from both design and methodological points of view as it allows one to identify key elements in creativity and creative thinking and provides a structured approach to the research and development of these aspects.

The difference between the weak core and the strong core from the design point of view

AbstractFrom a normative viewpoint, there is no compelling reason for preferring the weak over the strong core, and vice versa. However, the situation changes significantly from a mechanism design perspective. We work in a rights structures environment, where the role of the social planner is to allocate rights to individuals or coalitions which allow them to change the status-quo state. While coalitions are irrelevant for implementation in weak core (Koray and Yildiz in J. Econ. Theory 176:479-502, 2018; Korpela et al. in J. Econ. Theory 185:104953, 2020), our results show that they are fundamental for implementation in strong core. We fully characterize the implementation of social choice rules in strong core to outline this distinction. For robustness, we also characterize double implementation in weak and strong core which we show to be equivalent to implementation in weak core. Finally, we show that this equivalence breaks down in the more realistic case of implementation by codes of rights, where the set of states coincides with the set of outcomes.

Sensitivity Analysis of Scallop Damper Seal Design Parameters for Leakage and Static Performance

The leakage characteristics and static stiffness of scallop damper seals have a significant impact on rotor vibration and stability. A parameter sensitivity analysis model for geometrical parameters in scallop damper seals was developed using a design of experiments (DOE) approach. The method employed a central composite design, integrating factorial, axial, and center points to assess non-linear effects efficiently. And the effects of radial clearance, cavity depth, and length–diameter ratios on leakage performance and rotor stability were investigated. The leakage rate, flow-induced force, and static stiffness coefficient for 15 different combinations of geometric parameters at eccentricities of 0.2 and 0.4 were numerically calculated. The results show that eccentricity has little effect on leakage and its parameter sensitivity. Larger cavity depths and length–diameter ratios are beneficial for seal leakage performance. The tangential force increases with increasing eccentricity but decreases with increasing radial clearance, while it first decreases and then increases with the increase in the cavity depth and length–diameter ratios. Additionally, the radial force decreases with the increase in the length-to-diameter ratio and increases first and then decreases with the increase in radial clearance. The parameter level in this study is defined as the ratio of the actual parameter value to the maximum parameter value. Static direct stiffness reaches its maximum value at a radial clearance level of 30.2%. It remains positive within a cavity depth range of 92.3~100%, as well as a length–diameter ratio range of 0~20.3%. The static cross-coupled stiffness gradually decreases with the increase in radial clearance but first decreases and then increases with the increase in the cavity depth or length–diameter ratio levels. The research results presented in this paper can serve as a reference for the analysis of the performance and design of scallop damper seals.

Toward Dose Prediction at Point of Design.

Human dose prediction (HDP) is a useful tool for compound optimization in preclinical drug discovery. We describe here our exclusively in silico HDP strategy to triage compound designs for synthesis and experimental profiling. Our goal is a model that provides a preliminary estimate of the dose for a given exposure target based on chemical structure. First, we construct machine learning models to estimate rat pharmacokinetics, which are subsequently allometrically scaled to estimate human pharmacokinetics. Second, we establish a 10 nM free concentration target for early HDP where potency data are not yet available. Finally, we assess the uncertainty associated with each model and propagate these into the final estimate, providing us with actionable guidance on the level of accuracy of these estimates. We find that this strategy can reduce preparation of compounds with poor properties relative to an unstructured approach, but extensive experimental testing remains required.

Abstract IA004: Overcoming traditional design limitations with AI-based discovery

The properties of a new drug are set at the point of design, including any potential design flaws. Many small molecules that make it to human trials fail to progress beyond Phase 1 due to these flaws, which manifest as unacceptable side effects (either alone or in combination), meaning the drug (and therefore the pathway it is modulating) can never be adequately evaluated. This presentation will highlight how, through the thoughtful generation of a precise target candidate profile (TCP) and the subsequent use of GenAI, clinical candidates can now be precision designed to more exacting standards. Such molecules have the potential to have improved therapeutic indices, even against protein targets that are usually associated with mechanism-based adverse events. Citation Format: David J. Hallett. Overcoming traditional design limitations with AI-based discovery. [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Optimizing Therapeutic Efficacy and Tolerability through Cancer Chemistry; 2024 Dec 9-11; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(12_Suppl):Abstract nr IA004

Landscapes of Housing

The concepts of residential space and housing, created by Yugoslav modernist Juraj Neidhardt through the collaboration with architect Dušan Grabrijan, have yet to be investigated systematically, especially from the urban design point of view. As rooted in joint ethnographic research of local Bosnian dwelling culture and vernacular architecture, Neidhardt developed a specific approach to modern neighborhood design compared to the prevalent scientific-planning approach in post-war modernism. From the perspective of urban design, Neidhardt examined the possibilities of conceptualizing more humane dwellings in the context of rapid housing construction in post-war Yugoslavia and Bosnia and Herzegovina, looking through the lens of traditional dwelling culture in which architecture is a mediator between man and landscape. The article will distill, describe, and interpret Neidhardt’s ideas of a modern neighborhood that arise from elaborated descriptions of the Bosnian vernacular architecture articulated in close collaboration with Dušan Grabrijan. Neighborhood concepts have significantly different densities and forms, as designed and redesigned through four decades. Nevertheless, the fundamental design principles common to all neighborhood concepts are recognized, focusing on the dichotomy of architecture and landscape in terms of form and meaning. The research was based on analyzing the author’s books and published texts and designs in several Yugoslavian architectural journals.

Data Centers Expansion in Italy: Energy Considerations and Big Data Analysis

The need for a Mediterranean hub that allows the spread of artificial intelligence has induced the wind of data center expansion to blow in Italy. Based on public and web data (therefore of only approximate and illustrative reliability), a possible proto-plan is outlined hereinafter that highlights - together with the need for time and cost refinements to reach a real concrete plan - how the construction of data centers should proceed on a broad front in order to optimize the plan objectives. These objectives include, in addition to operational reliability, also the times and costs associated with construction. Some elements of the plan are therefore discussed below from a technical-economic and organizational point of view, but also from a design point of view, useful for localization and for plant optimization, especially for the energy part (in its varioustechnological options) in a European context. After discussing the need for a data center to also operate off-grid, as well as the need for regulation and power factor correction for electrical supplies, the opportunity of an operational index to evaluate performance is highlighted, which should be part of the guaranteed parameters. For this purpose, an estimation index of Normalized Annual Processing Power (NAPP) is provided as a proposal-example to be used in the case of “turn-key” type construction contracts through a “main contractor” or through an “architect-engineer” with managerial functions. Finally, ethical and responsibility aspects are highlighted that concern the ownership of data and the purposes of their use, especially in general cases of experiments that involve a social body worried about generalized social control.

A Practical Approach to Modeling and Performance Analysis of a Turboshaft Engine Using Matlab

This article presents a detailed approach to constructing a numerical model of a free power turbine engine specifically designed for performance analysis in the Matlab R2024b environment. The core innovation of this model lies in its integration of precise engine geometry parameters, calculated at the design point, and performance characteristics of key components such as the compressor and power turbine. These components are modeled to reflect significant variations in their performance based on changing operational conditions, including rotor speed and environmental factors. To validate the model’s assumptions, data from the PZL-3W engine were used. The model was created by meticulously incorporating the engine’s specific design characteristics, allowing for an in-depth examination of how performance characteristics shift with adjustments to high-pressure rotor settings or changes in ambient conditions. The resulting calculations demonstrated a high level of agreement between the model’s output and empirical data available for the PZL-3W engine, as well as with data found in the relevant scientific literature. This alignment underscores the model’s robustness and reliability in simulating engine performance across a range of operating scenarios, making it a valuable tool for further engineering analyses and optimization of free power turbine engines and their possible application.

Building Narratives and Probing Concepts: Preparing Materials for Co-Design with Autistic Livestreamers

Based on ten semi-structured interviews with autistic Twitch streamers, we introduce a series of scenario-based design narratives coupled with technology design concepts as a starting point for co-design discussion about autistic streaming. This work builds on prior thematic analysis of the unique intersection between autism and livestreaming. Our user-centered scenarios highlight the needs, goals, and challenges of autistic individuals in livestreaming contexts. By using evocative narratives, the scenarios serve to facilitate empathy and deeper engagement with the needs of autistic users, and help facilitate and support co-creative dialogues and discussions about new technology designs. We contribute this starting point for researchers and technology designers to co-create more inclusive and supportive online environments for autistic users.

Effect of Propeller Face Camber Ratio on the Reduction of Fuel Consumption

This paper presents the effect of the face camber ratio (FCR) on propeller performance, cavitation, and fuel consumption of a bulk carrier in calm water. First, using a developed propeller optimization model coupling a ship performance prediction tool (NavCad) and a nonlinear optimizer in MATLAB, an optimized propeller design at the optimal engine operating point with minimum fuel consumption is selected. This optimized propeller demonstrates superior fuel efficiency compared to the one selected by using the traditional selection methods that prioritize only higher propeller efficiency. Afterward, the FCR is applied to the propeller geometry to evaluate the effect on propeller performance. The open water curves of propellers with different FCRs ranging from 0% to 1.5% are computed based on empirical formulas and computational fluid dynamics (CFD) simulations. Between the two techniques, a good agreement is noted in verifying the predictions. Then, the open water curves from CFD models are implemented into NavCad to evaluate the overall hydrodynamic performance of the propeller at the design point in terms of efficiency, quantify reductions in fuel consumption, and analyze changes in cavitation and noise criteria. The computed results show a reduction in fuel consumption by 3% with a higher FCR. This work offers a preliminary evaluation of propeller performance-based FCR and shows its benefits. This technique offers a promising solution for improving the energy efficiency of the ship and lowering the level of fuel consumption and exhaust emissions.

Experimental and numerical investigation of a novel inlet for boundary layer ingesting propulsion systems

Boundary Layer Ingestion (BLI) propulsion systems have the potential to significantly enhance aircraft performance, particularly by improving fuel efficiency and reducing emissions. However, the high total pressure losses and distortions at the outlet of the BLI inlet normally restricts the development of BLI propulsion systems. This paper introduces and investigates a high-performance dual-sided BLI inlet configuration suitable for a large amount of boundary layer ingesting through a combination of computational and experimental methods. The dual-sided BLI inlet has two air entrances located at the top and bottom of the aircraft's rear fuselage, with the two ducts from the upper and lower inlets deflecting towards each other and converging at the same annular outlet. Simulation results indicate that the dual-sided BLI inlet prevents the concentration of low-energy flow observed with single-sided inlets, thereby reducing outlet distortion. Additionally, high-speed wind tunnel tests were conducted to validate the design's feasibility. The test results indicate that the dual-sided BLI inlet demonstrates good performance at the design point (Mfar=0.75, MAIP=0.50, δ/h≈45 %). The total pressure recovery coefficient σfar=0.907 and σin=0.995, the outlet total pressure distortion index DC60=0.24, and the outlet swirl intensity is minor. In conclusion, the novel BLI inlet maintains robust performance under designed conditions, fulfilling the engine's stability requirements.