bluuebunny/crossref_metadata_2025 huggingface dataset:
Contemporary Challenges in the Management of Asthma and Chronic Obstructive Pulmonary Disease: Expert Perspectives on Optimising Outcomes Through Guidelines Implementation, Inhaler Selection, and Patient Engagement
Authors: Vasankari Tuula , Lavorini Federico , Janson Christer , Lehtimäki Lauri , Bateman Eric , Singh Dave , Ulrik Charlotte Suppli , Woodcock Ashley , Agusti Alvar
Published: October 2022

Asthma and chronic obstructive pulmonary disease (COPD) affect millions of people throughout Europe, being one of the leading causes of death in the continent. Both conditions also impose considerable morbidity on patients, adversely affecting individuals’ physical and psychological wellbeing, and their capacity to live and work normally. Asthma and COPD also impose a substantial economic burden on healthcare providers and wider society through both direct and indirect costs of care.

Inhaler-delivered therapy has been central to the successful management of both conditions for several decades. Advances in device technology and understanding of the pathophysiology of both conditions (while theoretically introducing greater flexibility and responsiveness into the repertoire of inhalation therapies) have also added complexity and sometimes confusion into the task of identifying the precise combination of medication and delivery device best suited to the needs of individual patients.

Recently published multinational consensus reports have set out best-practice frameworks for the management of both asthma and COPD. Presentations at the two symposia summarised in this report examined the implications of these guidelines for the treatment of both conditions. Special focus was on dry power inhalers (DPI) as a means of delivering effective treatment that combines ease of use and widespread acceptance among patients, with the potential to reduce medically-related emissions of greenhouses gases compared with pressurised metered-dose inhalers (pMDI).

The authors emphasised the importance of patient partnership in determining the care plan, including the choice of both inhaler device and treatment; the benefits of regular monitoring of adherence to the treatment for both patients with asthma and COPD; and the benefits of simplicity, using one type of inhaler where possible to minimise critical errors in inhalation technique.
Surgical Management of Superior Sulcus Tumours: A 20-Year Experience of an Oncological Referral Centre
Authors: Spaggiari Lorenzo , Bertolaccini Luca
Published: October 2022

The authors present a study that investigated the clinical features and therapy of superior sulcus non-small cell lung cancer during a 22-year period.
Experimental study on vortex sound interaction of acoustic resonance and its suppression in a flow duct
Authors:   School of Safety Science and Engineering, Civil Aviation University of China, Fu Yilei ,   School of Safety Science and Engineering, Civil Aviation University of China, Zhang Jiaqi , Hong Zhiliang ,   School of Safety Science and Engineering, Civil Aviation University of China, Yang Mingsui ,   The 11th Research Department, AECC Shenyang Engine Research Institute
Published: October 2022

Acoustic resonance induced by vortex shedding in flow passages is widely detected in various of engineering applications such as aeroengine compressors, tubular heat exchangers and so forth. The coupling between vortex and sound is still an open issue. Experimental results of vortex sound interaction in acoustic resonance induced by vortex shedding from bluff bodies in a flow duct are presented in this paper, with special attention being paid to the suppression strategy using acoustic treatment on the duct wall. Two sets of experiments, including hard wall condition and non-locally reacting liner condition, are conducted in a low-speed wind tunnel. The “dominant region” and “synchronous region” are observed in both the lock-in region of sound wave and vortex shedding signal. The frequency of the acoustic β-mode of the test section is different from the dominant frequency of the dominant region and the locked frequency of the synchronous region. And acoustic feedback plays an important role in it. The acoustic liner can effectively suppress the process of acoustic feedback. When one side of the duct wall is replaced by a non-locally reacting liner with a sound absorption coefficient of approximately 0.4, the lock-in region disappears and the resonant amplitude of sound pressure and the corresponding fluctuation velocity are greatly reduced, which indicates a convenient strategy for acoustic resonant suppression.
Aeroengine Multi-Fault Diagnosis Based on Hierarchical Multi-mode Filtering
Authors:   School of Power and Energy,Northwestern Polytechnical University, Jiang Hao , Ren Xinyu ,   School of Power and Energy,Northwestern Polytechnical University, Fang Xiaojian ,   School of Power and Energy,Northwestern Polytechnical University
Published: October 2022

Carry out model-based online fault diagnosis for aero-engine sensors, actuators and components. Traditional methods use a set of filters to estimate the current state of the engine, and then process the estimated residuals of each filter to obtain the diagnosis result. For single engine faults, this method has a good diagnostic effect, but when double engine faults are considered, the amount of calculation will greatly increase, and the accuracy and real-time performance of fault diagnosis cannot meet the requirements. In this regard, this paper proposes a fault diagnosis algorithm based on hierarchical multi-mode filtering, which combines the advantages of hybrid Kalman filtering and multi-mode adaptive filtering algorithms, and uses a hierarchical diagnosis architecture for fault diagnosis. First, establish a hybrid Kalman filter bank of sensors, actuators and components, and then layer them. The first layer diagnoses the normal state of the engine and single fault conditions, and the second layer diagnoses the double fault conditions on the basis of the first layer fault diagnosis, and finally outputs the diagnosis results comprehensively. This method can meet the real-time and accuracy requirements for single and double fault diagnosis of the engine.
INFLUENCE OF UNEVEN BLADE TIP CLEARANCES ON AEROACOUSTIC CHARACTERISTICS OF CENTRIFUGAL COMPRESSORS
Authors:   School of Mechanical Engineering Beijing Institute of Technology, Zhang Meijie , Qi* Mingxu ,   School of Mechanical Engineering Beijing Institute of Technology, Zhang Hong ,   School of Mechanical Engineering Beijing Institute of Technology
Published: October 2022

The blade tip clearance is a crucial factor in the compressor performance and the aeroacoustics. There are usually main blades and splitter blades, two different types of blades in centrifugal compressors. Keeping almost the same work input, three different tip clearance configurations were designed in which the tip clearance gaps of main blades and splitter blades were uneven. Then experimental investigations were carried out to study the influence of uneven tip clearances on the aeroacoustic characteristics of centrifugal compressors. The results showed that larger main blade tip clearances or larger splitter blade tip clearances would induce rotating instabilities (RI) near flow instability boundary at low rotating speeds. However, the broadband noises below the blade passing frequency (BPF) in the case with uneven blade tip clearances were suppressed significantly which might be due to the incongruous interaction between the tip clearance leakage flows of main blades and splitter blades. In addition, the blade nonsynchronous vibrations (NSV) were observed in the analysis of the frequency spectrum of far-field noise in the case which had smaller main blade tip clearances and larger splitter blade tip clearances. Based on the jet core feedback theory, a physical explanation was given for NSV occurred in this case.
Geometric measurement of film-cooling holes using co-axial light-field imaging
Authors:   Shanghai Jiao Tong University, Xu Shengming , Zeng Fei ,   AECC Hunan Aviation Powerplant Research Institute, Shi Shengxian ,   Shanghai Jiao Tong University
Published: October 2022

In a high thrust-weight-ratio aero-engine, turbine blades are exposed to extremely high temperature and pressure which sets higher demands in the blade cooling technology. The mainstream types of cooling include internal airflow cooling, film cooling, and thermal barrier coating. Cooling efficiency is substantially subject to the machining accuracy of blades, more specifically the film-cooling holes on them. A coordinate measuring machine(CMM) is extensively used in the measurement and inspection of turbine blades which enables measuring blade patterns and building geometric models. However, the probes utilized by a CMM are similar in scale to that of a film-cooling hole, making it almost impossible for a CMM to measure film-cooling holes. The probes are prone to damage and the measurement accuracy cannot be guaranteed. This paper proposed a non-contact measuring technique to cope with the inspection of turbine blades. The technique is based on light-field imaging. A light-field camera with a high magnification lens is applied to caperture images of film-cooling holes and their neighborhood which are then inputted to a 3D reconstruction algorithm. A point cloud is derived by the algorithm and fundamental parameters are extracted. The whole inspection requires only one platform and is able to measure shaped film-cooling holes.
LOCALIZATION OF BREATHING CRACKS IN ENGINEERING STRUCTURES WITH TRANSMISSIBILITY FUNCTION-BASED FEATURES
Authors:   School of Power and Energy, Northwestern Polytechnical University, Li Quankun , Li Zihao ,   School of Power and Energy, Northwestern Polytechnical University, Liao Mingfu ,   School of Power and Energy, Northwestern Polytechnical University, Zhang Kang ,   Sichuan Gas Turbine Establishment, Aero Engine Corporation of China (AECC)
Published: October 2022

Structures such as fuselage, blade and wing in aeronautical and astronautical engineering are often subjected to cyclic loads in their service life, which in turn causes breathing cracks in these structures. To provide much more precise position of breathing cracks in structures and avoid structure failure, a local vibration-based approach using transmissibility function-based features is proposed and verified in this study. In the new method, nonlinear dynamic behaviour of cracked structures is simulated by a chain-type multiple-degree-of-freedom (MDOF) model, in which breathing cracks are represented as related nonlinear connections between masses. By modifying local structural physical parameters (mass, stiffness or damping coefficient), transmissibility function-based features are derived from cracked structures only and corresponding damage indicator is calculated for fault localization. Based on results of simulations on the chain-type model with breathing cracks, the effectiveness and practicability of damage indicator and method are verified and demonstrated. Moreover, merits, drawbacks and further development of this method are summarized and discussed.
Investigation of a WallDistanceFree Spalart–Allmaras Turbulence Model for Turbomachinery Applications
Authors:   School of Power and Energy, Northwestern Polytechnical University, Yin Junjie , Wang Dingxi ,   School of Power and Energy, Northwestern Polytechnical University
Published: October 2022

The Spalart–Allmaras turbulence model has been widely used in solving the Reynolds averaged Navier–Stokes equations. Like all partial differential models, it requires wall distance to solve the equations. Calculating wall distance is not an easy task, particularly for complex geometries. Furthermore, it is also very timeconsuming if an analysis involves dynamic mesh deformation. To overcome the drawback of wall distance calculation, a walldistancefree modification to the Spalart–Allmaras turbulence model was proposed a few years ago and was evaluated for external flows. Nevertheless, the use of the walldistancefree model has been rarely reported in the open literature since its introduction. In this investigation, the walldistancefree variant of the Spalart–Allmaras turbulence model will be implemented in an existing flow solver which already has the standard Spalart–Allmaras turbulence model. Many aspects of the variant model, in terms of implementation issues, solution stability and convergence, modeling accuracy, and computational time cost will be investigated through typical case studies.
Range of application for a self-sufficient energy system with hydrogen as energy carrier in remote areas
Authors:   Technical University of Munich Department of Mechanical Engineering Institute of Plant and Process Technology, Jurisic Tin , Rehfeldt Sebastian ,   Technical University of Munich Department of Mechanical Engineering Institute of Plant and Process Technology, Kneller Michel ,   ILF Beratende Ingenieure GmbH, Klein Harald ,   Technical University of Munich Department of Mechanical Engineering Institute of Plant and Process Technology
Published: October 2022

A self-sufficient hydrogen energy system provides energy directly and by converting electricity into hydrogen and reconverting it when needed. In order to get a broader understanding of the technical feasibility for this concept, power, storage and size ranges of the system need to be elaborated. The subsystems such as renewable energy source, hydrogen generation, storage and reconversion are discussed. In addition, the technology evaluation drawn from the state-of-the art form the basis for the energy system concept. Taking specific requirements for the off-grid system into consideration, the process is modeled for the stationary case providing the power outputs for hydrogen generation and reconversion as well as storage capacities. A comparison to conventional self-sufficient energy systems such as diesel generators is made and the range of application for containerized hydrogen self-sufficient energy systems is narrowed down.
Effects of Different CO2 equations of state on Condensation Position in Numerical Investigation
Authors:   North China Electric Power University, Zhang Lei , Yang Zhenyu ,   North China Electric Power University, Dong Zheng ,   North China Electric Power University, Zhang Qian ,   North China Electric Power University, Sun Enhui ,   North China Electric Power University
Published: October 2022

Supercritical CO2 power generation system have been gaining interest in the field of thermal power conversion due to its high efficiency and compactness. The low power consumption of the near-critical compressor is the key factor for its high efficiency. However, when CO2 is pressurized from a near-critical state to supercritical state, condensation may occur locally due to the high nonlinear behavior of the flow properties in the compressor. In the numerical simulation of compressor, sharp change of CO2 fluid properties near critical point also brings difficulties in capturing the condensation phenomenon. In order to explore the influence of fluid properties on the condensation phenomenon, this article first discussed the difference among the RK equation of state, the PENG-ROB equation of state, and the CO2 real fluid properties from the NIST REFPROP database. Then a numerical three-dimensional simulation was done using a de Laval nozzle model and the results were used to study the influence of fluid properties calculated from different equations of state in CO2 numerical simulation on the condensation position.
Forced response analysis of the rotor blade rows with the ROM-based aeroelastic model
Authors:   Northwestern Polytechnic University, Yang Jingyuan , Zhang Weiwei ,   Northwestern Polytechnic University
Published: October 2022

A rapid method, based on the reduced order model (ROM), is developed to analyze the forced response of the rotor due to the rotor-stator interaction. The unsteady aerodynamic force acting on blades is divided into two parts according to the source. One part is due to the rotor-stator interaction, while the other is due to the blade vibration. The aerodynamic forces due to the rotor-stator interaction is regarded as excitation, while an unsteady aerodynamic force model is built to calculate the unsteady aerodynamic force by the blade vibration. Then an aeroelastic model is built via coupling the structural equation with the unsteady aerodynamic force model. The aeroelastic model is calculated with the excitation of the aerodynamic forces due to the rotor-stator interaction. The forced response for the 50% height of the NASA67 secondstage rotor is analyzed by the CFD/CSD method, the ROM method and the energy method via time domain method respectively. Compared with the energy method, the relative error of the resonant amplitude is fallen from 12.5% to 0.06% by ROM method, while the efficiency is improved by 46.36 times as compared with the CFD/CSD method. In order to discuss the influence of structural parameters, the forced response analysis is conducted by the ROM method with various mass ratios and structural frequencies. It illustrates that the effect of fluid-structure coupling is crucial to the low-massratio structure. Furthermore, the structural frequency is not exactly coincident with the excitation frequency when the response amplitude reaches its peak.
Assessment of Adaptive chemistry via prepartitioning of composition space and mechanism reduction for the Simulation of MILD Combustion
Authors:   Université Catholique de Louvain, Pagani Pietro , Contino Francesco ,   Université Catholique de Louvain, Parente Alessandro ,   Université libre de Bruxelles
Published: October 2022

Moderate or Intense Lowoxygen Dilution (MILD) combustion has become increasingly important as it ensures high combustion efficiency with low pollutant emissions. However, modelling this regime is much more difficult than for conventional flames due to the strong coupling between turbulent mixing and chemical kinetics. The use of detailed chemistry has therefore become an essential requirement in CFD (Computational Fluid Dynamics) simulations, although reducing the chemical mechanism is an effective way to dramatically reduce the computational cost. One globally reduce mechanism is suboptimal as it nees to be comprehensive for all the thermochemical conditions, yet the on-the-fly chemistry reduction carries also some computational overheard. Therefore the methodology SPARC (SamplePartitioning Adaptive Reduced Chemistry) for the inclusion of detailed chemistry is investigated in this work. It alleviates the overhead associated to the on the fly reduction by building a library of locally reduced mechanisms in the preprocessing step. The current paper focuses on an apriori assessment of SPARC for simulating Delft jet in hot coflow (DJHC) burner fed with natural gas. The analysis will assess the level of reduction reached in the preprocessing step with different chemical mechanism, Gri3.0_HT, POLIMIC1C3_HT and POLIMIC1C3HT_NOx. First the clustering algorithm is tested with datasets of different sizes. Then the impact of partitioning parameters on the degree of reduction is quantified.
Study on dynamic characteristics of a combined air pressure reducing valve
Authors:   AECC Xi'an Engine Control Technology CO., Ltd., Bing CAI , Yuhu Liu ,   AECC Xi'an Engine Control Technology CO., Ltd., Xiaofeng Cheng ,   AECC Xi'an Engine Control Technology CO., Ltd.
Published: October 2022

Aiming at a kind of combined high pressure reducing ratio air pressure reducing valve with two stages in series, computational fluid dynamics (CFD) method is used to study the flow field characteristics of the pressure reducing valve. For different pressure reducing states, the dynamic characteristics of the pressure reducing valve are studied through unsteady simulation, and the variation law of characteristic parameters with time in typical processes such as starting, pressurization and decompression is analyzed. The results show that the variation law of the parameters such as pressure of the chamber and flow rate of valve is different in different pressure reducing states and working processes, but the flow field of the pressure reducing valve has reasonable aerodynamic damping characteristics, which can achieve stable operation in the regulation process in a large range of pressure reducing ratio, and has good dynamic characteristics.
NOISE OF FUTURE AIRCRAFT PROPULSION: SOURCES AND DESIGN CONSIDERATIONS
Authors:   Aristotle University of Thessaloniki, Protopapadakis Georgios , Gkoutzamanis Vasilis ,   Aristotle University of Thessaloniki, Vouros Stavros ,   Mälardalen University, Kyprianidis Konstantinos ,   Mälardalen University, Kalfas Anestis I. ,   Aristotle University of Thessaloniki
Published: October 2022

This paper attempts to reduce the gap, when it comes to future aircraft concepts noise and aeroacoustics, and at the same time introduce basic noise aspects for people unfamiliar to it. This is performed by taking into account the following four stages: Identification of conventional aircraft noise sources, overview of the aeroacoustics of future aircraft configurations, derivation of conceptual design considerations for noise issues, and finally, insight on the impact of technology advancements on certification. More specifically, a holistic overview of the aeroacoustics of aircraft was performed. The noise sources were described and made available for those unacquainted with the subject. Aeroacoustic behavior of ContraRotating Open Rotors, Boundary Layer Ingestion and Distributed Propulsion concepts was studied trough the most recent and relevant literature. The phenomena causing noise were highlighted, and the differences between conventional and future designs detected. It was found that generally noise sources are similar, but the intensity of some can be significantly altered. Early design phase guidelines were extracted for each of the concepts. The design considerations are grouped into a matrix showing the relative effect of each on noise emissions. With these guidelines, it is possible to perform design choices in the conceptual level of fidelity for future aircraft concepts. Furthermore, certification aspects and observations considering its future development are presented. Noise emissions are expected to change, and thus certification must be adapted to it. Furthermore, in this quick advancing technology field, virtual certification is advised to be used.
Study on Unsteady Flow Characteristic in a Transonic Axial Compressor Rotor at Near Stall Condition
Authors:   Northwestern Polytechnical University, Zhang Ziyun , Wu Yanhui ,   Northwestern Polytechnical University, Chi Zhidong ,   Northwestern Polytechnical University
Published: October 2022

In this paper, the three dimensional single-channel numerical simulation has been undertaken to analyze unsteady flow characteristic and fluctuation mechanism at near stall condition in a transonic compressor rotor. It has been found that at near stall condition, strong unsteady fluctuations appeared at the region which is closed to the pressure surface (PS) at leading edge and the downstream of shock wave in rotor tip. Then, detailed analysis of the tip flow field showed that the interaction between tip leakage vortex (TLV) and shock waves causes the spiral type breakdown of TLV,and caused reverse flow periodic shedding in the recirculation region, both effects gived rise to the large fluctuation of the rotor tip field. Periodic shedding of the reverse flow affected the pressure distribution of blade pressure side so that the blade tip was unloaded and the tip leakage vortex breakdown was thus suppressed, thereby forming a self-sustaining unsteadiness. The TLV breakdown was the decisive factor leading to the flow unsteadiness.
ANALYSIS OF STRUCTURALLY AND AERODYNAMICALLY MISTUNED OSCILLATING BLADEROW USING FULLY-COUPLED METHOD
Authors:   Department of Engineering Science University of Oxford, Phan H. M. , He L. ,   Department of Engineering Science University of Oxford
Published: October 2022

Turbomachinery blades are normally designed based on the tuned idealization. However, blade-to-blade variations will inevitably occur due to manufacturing and assembly processes as well as wearing and tearing during the operation. These variations are denoted as mistuning and it is known that mistuning can affect blade aeroelasticity performances. Although there have been various studies on mistuned cases, they typically are based on reduced methods with corresponding modeling assumptions. Direct fluid-structure coupled solutions of mistuned bladerows are rather limited, thus there is lack of clear and systematic understanding of physical behaviours and mechanisms of mistuned bladerows. The main objectives of the present work are two-folds. First, elucidate the basic vibration kinematics of a mistuned bladerow for both a structural mistuning and an aerodynamic mistuning. Second, examine the effects of mistuning on flutter susceptibility for a specific alternating arrangement. The present results show that firstly a mistuned configuration tends to vibrate with the same frequency and inter-blade phase angle. Vibration amplitudes of the blades however vary with a strong mode localization effect for a structural mistuning. For the concurrent structural-aerodynamic mistuning, the localization is stronger than the standalone structural mistuning case. Secondly, a monotonic increase of the aeroelastic stability with structural mistuning is observed. On the other hand, the aerodynamically mistuned cascade shows a stabilizing effect at a small amount of mistuning but exhibits a destabilizing effect at a large mistuning. At a low reduced frequency condition, there is a striking difference between the aerodynamically tuned and mistuned bladerows. Although the tuned cascade is stable, the aero-mistuned cascade can experience flutter. More remarkably, an additional structural mistuning seems to enhance the localization effect, leading to a larger vibration amplitude of the most unstable blade.
INFLUENCE OF AXIAL GAPS ON FORCED RESPONSE OF DIFFERENT MODE SHAPES IN A LOW-PRESSURE COMPRESSOR
Authors:   Institute of Turbomachinery and Fluid Dynamics Leibniz Universität Hannover, Hye Rim Kim Hye Rim Kim , Dajan Mimic Dajan Mimic ,   Institute of Turbomachinery and Fluid Dynamics Leibniz Universität Hannover + Cluster of Excellence SE2A – Sustainable and Energy Efficient Aviation Technische Universität Braunschweig, Joerg R. Seume Joerg R. Seume ,   Institute of Turbomachinery and Fluid Dynamics Leibniz Universität Hannover + Cluster of Excellence SE2A – Sustainable and Energy Efficient Aviation Technische Universität Braunschweig
Published: October 2022

Forced-response vibrations present an ongoing challenge in compressor design. This is especially apparent when axial-gap variations are considered: narrower gaps come with the benefit of a lower component weight. From the standpoint of aeroelasticity, however, this typically causes a stronger wake-induced excitation. Conversely, recent results have demonstrated an increased excitation of certain mode shapes with increasing axial gap. This paper investigates how the forced response of different mode shapes is affected by operating-point-related and design-related changes of the excitation source. Extensive time-linearised simulations are conducted at various off-design operating points with different mode shapes. Fourier-transformed gust boundary conditions are considered as the excitation source. The reduced frequency is identified as the determining factor for the sensitivity of the aerodynamic work with respect to axial-gap variations. Three reduced-frequency regimes are identified: moderate sensitivity for low reduced frequencies, low sensitivity for moderate reduced frequencies, and high sensitivity for high reduced frequencies. The cases with an inverse behaviour of the aerodynamic work with respect to the axial-gap variation are shown to occur in the low-sensitivity regime. It is demonstrated that they are a result of changes in the interaction of the incoming wakes with the rotor potential field.
Effects of Scaling Laws on Flow and Combustion Characteristics of Lean Premixed Swirl Burners
Authors:   Institute of Turbomachinery, School of Mechanical, WENDA XIE , BING GE ,   Institute of Turbomachinery, School of Mechanical, TING SHI ,   Institute of Turbomachinery, School of Mechanical, SHUSHENG ZANG ,   Institute of Turbomachinery, School of Mechanical
Published: October 2022

Modern heavy gas turbine combustors are always so huge in size that it is difficult and costly to do experiment. Thus, geometry scaling method has come into sight. In this paper, validated computational fluid dynamic (CFD) model was employed in total 8 simulations at various burner scales from 1/2 to 1/10, and the effect of constant DaI and constant Re scaling on flow and combustion characteristics of single lean premixed swirl burners were investigated. Under reacting condition, when scaling factor=1/2~1/5, DaI law was able to maintain good similarity. Finally, experimental study on 3/5 scale combustor under full operating condition is carried out. Results show that the flame features and emissions of scale model is consistent with prototype, which indict that constant DaI method is suitable for lean premixed swirl combustor scaling.
ANALYSIS OF COMBUSTION INSTABILITY MODES FOR A PARTIALLY PREMIXED SWIRL COMBUSTOR BY FLAME TRANSFER FUNCTION WITH THE THREE-DIMENSIONAL THERMOACOUSTIC MODEL
Authors:   Tongji University, Ke Enlei , Wang Ziyu ,   Tongji University, Cheng Jiaying ,   Tongji University, an Deng ,   Tongji University, Zhu Tong ,   Tongji University, Ji Chenzhen ,   Tongji University
Published: October 2022

The modes of combustion instability of a partially premixed swirl flame were investigated in the current work. The experimental tests of combustion instability were conducted on a laboratory-scale 25 kW combustor. To identify the characteristics of combustion instability in the premixed combustor, acoustic mode analysis was performed based on the three-dimensional thermoacoustic model, which was developed by inhomogeneous wave equation coupling with Flame transfer function (FTF). The FTF for characterizing the response of flame to the acoustic disturbance was simulated by CFD/system identification method. It was shown that the acoustic mode and dominant frequency was accurately predicted at 141.2 Hz by the proposed model when the FTF was considered, which was quite close to the experimental result of 139.2 Hz. The growth rates and frequencies of main modes of combustion oscillations were also presented and discussed. Later, the effects of the combustion chamber length on the oscillation modes were analysed when the additional length of chamber increased from 0.2 m to 1.0 m. It was found that the frequencies of main modes decreased when the length of chamber increased, while the growth rate of modes exhibited the different behaviours, and the dominant mode of the combustion system transformed from the second-order mode to the third-order mode.
NONLINEAR FLUTTER ANALYSIS OF THE ZERO NODAL DIAMETER OF A LABYRINTH SEAL
Authors:   School of Aeronautics and Space Universidad Politécnica de Madrid, Corral Roque , Greco Michele ,   School of Aeronautics and Space Universidad Politécnica de Madrid, Matabuena J. Luis ,   School of Aeronautics and Space Universidad Politécnica de Madrid
Published: October 2022

A non-linear reduced-order model has been used to assess the nonlinear stability of labyrinth seals in the case that circumferential variations are neglected. The model numerically solves the integral mass and energy equations of the seal for a prescribed motion until a periodic state is reached. For small vibration amplitudes, the work-per-cycle coincides with the one derived by Corral and Vega (2018, “Conceptual Flutter Analysis of Labyrinth Seals Using Analytical Models. Part I: Theoretical Background", ASME J. Turbomach. 140(10), pp. 121006) and Corral et al. (2021, “Higher-Order Conceptual Model for Seal Flutter”, ASME J. Turbomach. 143(7), pp. 071006), but for large but still realistic vibration amplitudes nonlinearities alter the stability limit. If the seal is supported on the lowpressure side high vibration amplitudes tend to stabilise the seal even more. However, linearly stable seals supported on the high-pressure side can become unstable. Nonlinear effects are significant when the discharge time of the seal is comparable to the vibration period but for high enough frequencies nonlinear effects can be disregarded. This latter limit is the most realistic and therefore it is concluded that nonlinear mechanisms can play a significant role in seal flutter this is not the case for the zero nodal diameter under realistic conditions.
Efficient Analysis of Unsteady Flows Within Multi-Stage Turbomachines Using the Coupled Time and Passage Spectral Method
Authors:   Northwestern Polytechnical University, Wang Ding Xi , Zhang Sen ,   Northwestern Polytechnical University, Huang Xiuquan ,   Northwestern Polytechnical University
Published: October 2022

A coupled time and passage spectral method has been proposed very recently for tracking blade wakes penetrating the immediate downstream blade row and reaching far downstream blade rows. To achieve an efficient numerical analysis, the number of time and space modes to be retained has to be limited, as the computational cost of such an analysis is at least proportional to the number of modes. In this study, time and space modes related to downstream propagation of blade wakes reaching beyond their immediate downstream blade row are ranked according to their amplitudes of flow quantities through a time domain harmonic balance analysis using a domain consisting of multiple blade passages for the third row to capture the wakes of the first row of a two-stage fan. Modes with significant amplitudes are identified and they are really sparse. This sparsity of significant modes provides the premise for an efficient analysis using the coupled time and passage spectral method. A guideline for a priori selection of time and space modes has been developed by analyzing the frequencies and nodal diameters of those significant modes. The guideline is subsequently verified through four different coupled time and passage spectral analyses with different levels of accuracy by including different time and space modes.
FLUTTER ANALYSIS OF BLISKS WITH FRICTION RING DAMPERS
Authors:   Department of Mechanical Engineering, Imperial College London, Suna Yekai , Yuanab Jie ,   Department of Mechanical Engineering, Imperial College London + Aerospace Centre of Excellence, University of Strathclyde, Sallesa Loïc ,   Department of Mechanical Engineering, Imperial College London
Published: October 2022

Aeroelastic flutter is a phenomenon when blades experience an aeroelastic selfexcitation from the surrounding air resulting in the full destruction of aeroengines. It poses a big challenge for aeroengine bladeddisks design, especially for integrally bladeddisks (blisks). The lack of friction interfaces in blisks drastically reduces structural damping making them more likely to experience aeroelastic flutter. One of the most effective approaches to improve the damping in a blisk is the use of friction ring dampers. This paper presents a numerical study to investigate the effects of friction ring dampers on the aeroelastic stability of blisks. A lumped parameter model is used to represent the blisk with a ring damper. Aeroelastic selfexcitations are simply represented by Van der Pol oscillators. The frictional contact between the blisk and ring damper is modelled by using Jenkins elements. Nonlinear modal analysis is used to compute the nonlinear dynamic response of the system. The results show that the friction ring damper can significantly reduce the risk of flutter and the amplitude of flutter induced limit cycle oscillations for a blisk by increasing the structural damping, especially at a high modal amplitude. The study also shows that the nonlinear modal analysis can efficiently identify the flutter boundary of such a strongly dissipated nonlinear system.
WHOLE ENGINE THERMAL ANALYSIS FOR CALCULATION OF CLEARANCES IN A HEAVY-DUTY GAS TURBINE
Authors:   MAPNA Turbine Engineering & Manufacturing Co. (TUGA), Shakeri Hossein , Shokrollahi Mohsen ,   MAPNA Turbine Engineering & Manufacturing Co. (TUGA), Poursamad Amir ,   MAPNA Turbine Engineering & Manufacturing Co. (TUGA)
Published: October 2022

In recent years, the power generation industry has witnessed a growing demand for higher power, efficiency and flexibility of heavy-duty gas turbines. One of the areas considered highly essential for higher efficiency in gas turbines is the control of the clearances. Precise evaluation of running clearances is a key to designing durable, reliable and efficient gas turbines. To this end, an accurate thermo-mechanical analysis is essential to ensure a safe operation and tight clearances in steady condition. This paper presents thermomechanical analysis of MAPNA MGT-70(3) heavy-duty gas turbine. The whole engine steady state coupled thermal and structural simulation is performed and the main procedure to obtain the clearances throughout the engine operation is discussed. The thermal study consists of a thermal-fluid model coupled with a 2D/3D FEM model. Different types of thermal boundaries are employed to ease the simulation of the engine thermal behaviour. In order to validate the numerical results, the field study of elongation is carried out. The axial elongation of rotor and casing in different engine conditions is obtained by means of proximity and LVDT sensors. Comparison of numerical and experimental results indicates a good accuracy of the results.
A three-dimensional freeform blading tool based on NURBS curves and surfaces implemented in Python
Authors:   Northwestern Polytechnical University, Li Weihua , Xu Shenren ,   Northwestern Polytechnical University
Published: October 2022

High performance compressor design requires the blades to be parametrized with highly three-dimensional freeform surfaces. One of the most widely used and versatile curve/surface modelling approaches in the CAD community is the Non-uniform Rational B-Spline (NURBS). Although blading tools are nowadays rather established and widely used in the turbomachinery industry, much of the work is either in legacy codes or done through commercial software, but a lot of knowwhy is missing. In this work, an effort to model the traditionally designed blades as well as more advanced modern designs with a unified approach is made, with the intention to understand the appropriate parametrization approach based on first principles and hopefully simplify the task of selecting a ‘suitable’ parametrization method for blade design practitioners. The Python code developed in this work can model axial and radial blade sections as well as three-dimensional blades including the hub and shroud profiles using NURBS. The control points for the NURBS curves/surfaces are computed using the input camber and thickness distribution. In addition, an automatic fitting algorithm based on optimization is also developed to re-parametrize blade shape provided in the form of point cloud. The results in the paper serve as a first step for building a simple yet versatile blading tool which will in the future be imbedded in an optimization workflow.
STUDI TINGKAT PENGETAHUAN DAN PERILAKU SWAMEDIKASI OBAT ANALGESIK PADA PASIEN DI APOTEK KOTA SAMARINDA
Authors: Susanti Aprilia Diah , Dewi Sinta Ratna
Published: October 2022

Self-medication is a behavior of the community to perform health treatment for themselves without having to consult with health workers. Analgesic is a non-steroidal anti-inflammatory drug (NSAID) group that is used to relieve pain, so it is often used by people to treat pain without losing awareness. This study aimed to describe the study of the level of knowledge and behavior of self-medication of analgesic drugs at the Samarinda City Pharmacy. This research is a type of quantitative research with the cross-sectional method. Sampling using non-probability sampling by purposive sampling. The sample used in this study was 147 respondents. The results showed that the majority of respondents on drug selection indicators (89.1%), drug class (83.65%), how to use (92.5%), and drug storage (75.96%) with behavioral levels on the selection indicator. drug (89.8%), drug class (87.1%), method of use (83.7%), and drug storage (77.5%). The patient's level of knowledge and the behavior of self-medication of analgesic drugs is included in the good category.
The Role of Partisanship, Identity and Incentives in Mobilizing Zambian Citizens
Authors: Jöst Prisca , Krönke Matthias , Lockwood Sarah , Lust Ellen
Published: October 2022

Citizens’ political engagement is widely regarded as vital for democracy. In Africa, however, the assumption has often been that citizens do not engage robustly in many activities such as campaigning or attending community meetings, with political participation primarily limited to voting. Thus, little research explores the drivers of these other vital activities. We aim to fill the gap, using an original survey experiment to explore the drivers of citizen participation in Zambia around the 2021 national elections. Contrary to widely held views in the literature, we find that partisanship is a critical driver of participation, with social incentives and ethnicity also playing important but less significant roles. Finally, we seek to understand the mechanisms underpinning these results, finding that citizens anticipate sanctions if they fail to support a co-partisan but not a co-ethnic candidate. These findings have important implications for understanding political engagement and democratic development throughout the region.
Persepsi Majelis Jemaat Tentang Ritus Kaus Nono Saeba Nono Di GMIT Jemaat Bethania Oetaman Klasis Amanuban Selatan
Authors: Nome Mety Selfina , Leobisa Jonathan , Luji Daud Saleh , Kasse Simon
Published: October 2022

The study was entitled “ The council’s perception of  kausnono saebanono Gmit at the bethania oetaman klasis amanuban selatan. the searcah problem is how the perception of the congregation of the rite of kausnono saebanono and how the impact on what church does not do it. the study aims to know and analyse the perceptions of the congregation and the effect on those who have not performed this ritual. this research is a type of qualitative research that produces descriptive data that is a picture of how the perpection of the congregation and impact for their lives. studies have shown that marriages are Timorese, and this kausnono sock rite is one of the most important things to do. and this ritual is performed by Timorese women who have completed religious and tribal marriages. this rite will be performed in women’s homes. the existence of a clan with varios live elves is believed by the tomorese to br an ancestral heritage. kausnono shirt present as givers to Timorese women to unite with klen’s husband both physically and spiritually.

Abstrak Indonesia 

Penelitian ini berjudul persepsi majelis jemaat tentang ritus kaus nono saeba nono di gmit jemaat bethania oetaman klasis amanuban selatan Masalah Penelitian adalah Bagaimana persepsi  Jemaat Terhadap Ritual Kaus Nono-Saeba Nono, dan Bagaiamana Dampak bagi masyarakat apabila tidak melakukan ritus ini?. Penelitian ini bertujuan untuk mengetahui dan menganalisis persepsi Majelis Jemaat dan dampak bagi mereka yang tidak melakukan ritus ini. Penelitian ini adalah jenis penelitian kualitatif yang menghasilkan data deskriptif yakni gambaran tentang bagaimana persepsi majelis jemaat dan dampak bagi kehidupan mereka. Dari hasil penelitian menunjukan bahwa di dalam perkawinan Atoni Meto, Ritus Kaus Nono dan Saeba Nono ini merupakan suatu hal yang wajib dilakukan. Dan Ritus Kaus Nono dan Saeba Nono ini hanya dilakukan oleh kaum perempuan yang di lakukan setelah menyelesaikan resepsi perkawinan, itupun dilakukan Ritus Kaus Nono dan Saeba Nono di rumah orang tua dari perempuan. Keberadaan suatu nama marga dengan berbagai peri kehidupan yang ada didalamnnya diyakini oleh orang meto, dibawa oleh para leluhur terdahulu. Kaus nono hadir sebagai pemberi identitas bagi perempuan meto untuk dapat menyatu dengan klen suami baik secara jasmani maupun spiritual.
Peranan Alat Musik Dalam Ibadah Gerejawi Abad I-V
Authors: Barus Rodenita Br , Gondowijoyo Antonius Richard
Published: October 2022

The problem in this paper lies in the use of musical instruments where in the Old Testament musical instruments played a very important role in worship, but in the New Testament the role of musical instruments is not explained and the Greek Orthodox Church does not use musical instruments in worship. This discussion aims to First, the role and use of musical instruments in worship ceremonies during the Old Testament period. Second, to answer the role and use of musical instruments in the ministry of the Lord Jesus and in the early church. The third, to explain why musical instruments are not used in the worship of the Greek Orthodox Church. So this paper uses a historical literature research approach. This paper will describe the role of music in the Old Testament, the role of music in the ministry of the Lord Jesus and in the early church, and the role of music in the Greek Orthodox Church. The conclusion of this paper proves that the role of music has different meanings in the Old Testament, the role of music during the ministry of the Lord Jesus and the early church, and the role of music in the worship of the Greek Orthodox Church.

Abstrak Indonesia 

Permasalahan dalam tulisan ini terletak pada penggunaan alat musik dimana dalam Perjanjian Lama alat musik sangat berperan dalam peribadahan, namun berbeda dalam Perjanjian Baru peran alat musik tidak dijelaskan dan Gereja Orthodox Yunani tidak menggunakan alat musik dalam ibadahnya. Pembahasan ini bertujuan untuk Yang Pertama, peran dan penggunaan alat musik dalam upacara peribadahan pada masa Perjanjian Lama. Yang kedua, untuk menjawab peran dan penggunaan alat musik dalam masa pelayanan Tuhan Yesus dan pada masa gereja mula-mula. Yang ketiga, untuk menjelaskan mengapa alat musik tidak digunakan dalam peribadahan Gereja Orthodox Yunani. Maka tulisan ini menggunakan pendekatan penelitian pustaka bersifat historis. Tulisan ini akan menjabarkan peran musik dalam Perjanjian Lama, peran musik dalam pelayanan Tuhan Yesus dan pada masa gereja mula-mula, dan peran musik dalam Gereja Orthodox Yunani. Kesimpulan dari tulisan ini membuktikan bahwa peran musik memiliki makna yang berlainan baik dalam Perjanjian Lama, peran musik pada masa pelayanan Tuhan Yesus dan gereja mula-mula, dan peran musik dalam ibadah Gereja Orthodox Yunani.
The success of biomaterial-based tissue engineering strategies for peripheral nerve regeneration
Authors: Jiang Yuhui , Tang Xiaoxuan , Li Tao , Ling Jue , Yang Yumin
Published: October 2022

Peripheral nerve injury is a clinically common injury that causes sensory dysfunction and locomotor system degeneration, which seriously affects the quality of the patients’ daily life. Long gapped defects in large nerve are difficult to repair via surgery and limited donor source of autologous nerve greatly challenges the successful nerve repair by transplantation. Significantly, remarkable progress has been made in repairing the peripheral nerve injury using artificial nerve grafts and a variety of products for peripheral nerve repair have emerged been approved globally in recent years. The raw materials of these commercial products includes natural/synthetic polymers, extracellular matrix. Despite a lot of effort, the desirable functional recovery still remains great challenges in long gapped nerve defects. Thus this review discusses the recent development of tissue engineering products for peripheral nerve repair and the design of bionic grafts improving the local microenvironment for accelerating nerve regeneration against locomotor disorder, which may provide potential strategies for the repair of long gaps or thick nerve defects by multifunctional biomaterials.