bluuebunny/crossref_metadata_2025_split huggingface dataset:
Features of commissioning a gas turbine unit with a low-emission combustion chamber
Authors: Vorotyntsev I E , Tyulkin D D , Fedorchenko D G , Tsybizov Yu I 
Published: May 2021

Abstract
Environmental safety issues are a priority in the modernization development of aviation or ground-based combustion chambers of gas turbine engines. In order to reduce the emission of harmful substances from combustion products, a low-emission combustion system, which is based on the concept of LPP (Lean-premixed and prevaporised), is being used today. This concept implements the principle of burning “ultra-poor” premixed air-fuel mixtures. The operational experience of combustion chambers developed in accordance with the indicated concept shows that one of the implementation problems is the difficulty in ensuring a good start. This paper presents the results of adjusting the operating process of a modern combustion chamber, launching a gas turbine unit, including drawing up a fuel supply control algorithm, experiments with igniting ignition devices and setting the gas turbine on idle mode. A feature of the commissioning work is the debugging of the operating process of the combustion chamber directly as part of the gas turbine unit, bypassing the traditional pilot-testing on the rig.
Comparative assessment of different hybrid propulsion system types’ efficiency for commuter aircrafts
Authors: Zakharchenko V S , Varyukhin A N , Rakhmankulov D Ya , Suntsov P S 
Published: May 2021

Abstract
This paper contains a comparative efficiency assessment of various concepts of hybrid propulsion systems (traditional, parallel turboelectric based on hybrid turboprop engines and serial hybrid) in accordance with the level of parameters of 2020 and 2030 for commuter aircrafts with capacity up to 19 passengers.
A method for checking the possibility of joint work of the auxiliary power unit and the starter
Authors: Popov G M , Zubanov V M , Novikova Yu D , Matveev V N , Baturin O V 
Published: May 2021

Abstract
This paper describes the algorithm developed by the authors for matching the workflow of the auxiliary power unit to the air turbine used when starting the engine. This technique is applied to determine the possibility of starting a gas turbine engine, calculate its time and basic parameters under all operating conditions (including in flight), as well as to select a new auxiliary power unit (APU) or an air turbine for an existing system. The developed technique considers structural, strength, operational and other limitations. The results were implemented as a computer program.
Development of an electric propulsion system demonstrator for an ultralight manned aircraft
Authors: Varyukhin A.N. , Zakharchenko V.S. , Geliev A.V. , Zhuravlev D.I. , Kiselev I.O. , Zagumennov F.A. , Kazakov A.V. 
Published: May 2021

Abstract
A description of a full electric propulsion system demonstrator with an energy source based on a battery pack for an ultralight manned Sigma-4 aircraft is presented. The main characteristics and functionality of the main units and devices of the electric propulsion system and its control system are presented.
3D optimization of the hollow fan blade internal structure
Authors: Salnikov Anton 
Published: May 2021

Abstract
Design optimization to reduce fan impeller mass is an important and urgent task. One way to solve the problem is to design a hollow blade. In addition to lightening the blade this also reduces the fan disk load, that in turn makes it possible to minimize the weight of the disk and the weight of the impeller as a whole. The hollow blade has a complex shape, and this significantly increases development time because modification of the structure in order to define its optimal shape is a very time-consuming and costly task. Therefore, automating this process and transforming it into an optimization task is very important and relevant. In this paper, an approach to optimal hollow fan blade design in the form of an optimization problem in 3D formulation is developed. To do this, a parameterized 3D model of the hollow blade was created in the ANSYS APDL environment. Using the developed model, a comparative optimization of a typical hollow blade was carried out.
A preliminary design of a schematic evaluation of low emission turbofan combustors
Authors: Krishna Vamsi U , Mitrokhov N V 
Published: May 2021

Abstract
This paper examines low emission combustion technologies (LECT) schemes suitable to the sixth generation high-bypass Turbofan engines designed to operate on narrow-body aircraft with a rated thrust (F∞ in kN) of 90-250 kilo-Newton(kN) and an overall pressure ratio of (Π∞) ≥ 30. The examined schemes are based on 11th regulatory standards of the Committee on Aviation Environmental Protection (CAEP). A brief overview on emissions is provided.
A new look at the application of metal matrix composites in a future aviation engine
Authors: Mileiko S T 
Published: May 2021

Abstract
Three types of composites, namely (1) carbon-fibre/metal-matrix, (2) oxide-fibre/molybdenum-matrix, and (3) oxide-fibre/high-entropy-matrix are considered as potential materials for future aviation engines. Technological schemes for producing the composites and their mechanical properties, as well as the potential of future development to maturing them are presented.
Tungsten Carbide Nanopowder Influence Study on Tensile Strength of GRP Specimens Made of Lavesan Glass Fabric and EPR 320 Momentive Epoxy
Authors: Gavrish V , Chayka T , Oleynik A. , Gavrish O. 
Published: May 2021

Abstract
This paper presents the test results of fiberglass samples consisting of glass fiber Lavesan (Italy) and a binder - EPR 320 epoxy resin modified with tungsten carbide (WC) nanopowder. The positive effect of nanopowder on the tensile strength and the increase in tensile strength of more than 1.5 … 2.5 times with the addition of additives in the mass concentration of 1 … 4% to the mass of the resin are shown.
Degradation of elastic characteristics of the CFRP used in the design of a gas turbine engine as a result of high-cycle fatigue damage
Authors: Nikhamkin M.Sh. , Solomonov D.G. 
Published: May 2021

Abstract
Carbon fiber reinforced polymers (CFRP) are increasingly being used in heavily loaded parts of aircraft engines. CFRP fan blades, vanes must successfully resist fracture due to high-cycle fatigue. One of the consequences of fatigue damage is a decrease in the rigidity of the material and a drop in the natural vibration frequencies of parts. These effects are of interest when developing fatigue fracture models and predicting durability. The purpose of this article is to develop a method and obtain experimental data on the decrease of elastic characteristics of CFRP as a result of progressive fatigue damage. The developed technique consists of two stages. During the first one, the natural frequencies and eigenmodes of the samples during their fatigue testing are experimentally obtained. During the second stage, the four elasticity parameters of the CFRP laminate monolayer are identified via the natural frequencies. The inverse numerical/experimental technique for material properties identification is applied. The dependences of elastic characteristics on the relative fatigue life are obtained as experimental results of both modal and fatigue tests. The results can be useful in studying the fatigue behavior of the examined materials and in creating methods for calculating fatigue life.
Studying the layer structure formation in laser additive manufacturing with AlMg6 alloy wire
Authors: Eremeev A.D. , Tsibulskiy I.A. , Akhmetov A.D. , Mukin D.V. , Davletshin A.O. 
Published: May 2021

Abstract
When processing aluminum alloys with repeated laser radiation, which is typical for both multi-pass welding and additive manufacturing, volatile chemical components are being burnt. Due to the processing zone overheating if there are residual stresses, the probability of there being structural defects and deformations and, consequently, distortion of the final shape of the sample increases. Studies of the wall’s structure forming process during laser additive manufacturing with AlMg6 alloy wire, fulfilled based on experiments and computational methods, allowed us to obtain the necessary data for optimizing the process and determining the laser treatment modes. The simulation of the thermocyclic effect of laser radiation on the wall and the selection of mode parameters for the optimal structure of the material and the shape of the bead were performed. The results for the chemical composition of the final material, the number of defects and mechanical properties were quite satisfactory.
An Assessment of the Controllability of the Main Parts of Aircraft Engines During Capillary Non-destructive Testing
Authors: Ospennikova O G , Kudinov I I , Golovkov A N , Generalov A S , Skorobogatko D S 
Published: May 2021

Abstract
The aim of this paper is to determine uncontrolled zones in the main parts of aircraft engines during capillary control using a luminescent set of flaw detection materials LYuM1-OV. The main factors affecting the defect detection process have been described. The approach not previously used in the practice of aviation enterprises has been experimentally tested. This approach takes into account the quality of applying a film-forming developer to various surfaces of structural elements of aircraft parts, using luminescence brightness samples. The research has clearly shown the control zones of holes of different diameters and herringbone type locks of different widths. It is established that the data presented in literature sources of technical and technological documentation on the controllability of holes and herringbone type locks differs from the experimental data.
Verification of a Mathematical Model of a Dry Friction Damper for a GTE Blade
Authors: Yakovkin V N , Besschetnov V A 
Published: May 2021

Abstract
This paper presents the verification of the mathematical model utilized to calculate the damping capacity of a dry friction damper. The mathematical model is based on determining natural frequencies and mode shapes, as well as relative characteristics of the friction energy losses. To estimate the applicability of the mathematical model to full-scale assemblies of a gas-turbine engine, the model was verified by the results of the experiment. The experiment was carried out in a laboratory where the damping capacity of the gas-turbine engine blade with a model under-platform damper was examined at constrained and damped oscillations. During the experiment multiple materials of contact pair were examined to determine how microslip affects the damping capacity. Based on the results of comparing calculations with the experiment, by selecting the dry friction coefficient, a good convergence on the oscillation decrement and natural frequency was achieved. The conducted research has shown that the mathematical model provides reliable results with Coulomb friction and can consider microslip effects on the damper capacity.
Modeling Rig Dynamics to Determine Dynamics of GTE Elements’ Performance under Shaker Conditions
Authors: Utkin A.O. , Yakovkin V.N. 
Published: May 2021

Abstract
During shaker tests to determine the strength properties of the test article, it can be difficult to shake the article to the required in the concentrator stresses. This may be due to the losses of the force transmitted from the shaker to the test article, which occur due to an improperly designed rig. Using some methods for rig designing, along with numerical modeling, provides the possibility to make an easy-to-excite rig with minimum loss of transmitted forces. This paper deals with the modeling of the “article – rig – shaker” system executing constrained oscillations under the influence of harmonic excitation. The model’s response dependencies on dynamic excitation caused by the oscillation frequency have been outlined. The excitation level’s influence on the dynamic parameters of the model have been analyzed.
The influence of nonuniform heat transfer coefficient distribution on the value of thermal deformations in mechanical gas dynamic seal rings
Authors: Vinogradov A , Novikova J , Shipunov V 
Published: May 2021

Abstract
Currently, many different aircraft engine types exist. They have a wide range of operating conditions: the flight speed can vary from zero to hypersonic values, the flight altitude from near-earth conditions to space flights. During the flight, loads are not kept constant. Engines have significant dynamic overloads, temperature and pressure differences, can operate in conditions of high humidity or dust, as well as in various aggressive environments. The development of aviation and rocket engine building is associated with a continuous increase in the working thermodynamical cycle parameters.
Further improvement of gas turbine engines (GTE) can be carried out in two directions. The first is using new advanced engine designs based on a modernized cycle, with a different fuel, original design, and power scheme. This direction also includes the application of new high-performance elements in the engine: bearings, seals, coatings, etc. The second direction is related to the improvement of existing structures, increasing their efficiency by more detailed working conditions forecasting based on the use of modern computing software systems. This article presents a study of the potential mechanical face gas dynamic seal (FGDS) in the support in an aircraft engine compressor. Aircraft engines are characterized by multi-mode operation and high temperature levels in the internal cavities. For a FGDS operating with a working gap of several microns the exact determination of the deformation value is a very important result of the design process. This article considers the influence of the convective heat transfer coefficients distribution on the value of sealing rings thermal deformations. To achieve this goal, two compaction models were created: the gas-dynamic model for determining the convective heat transfer coefficients in the ANSYS CFX software program; and the structural model for calculating the resulting deformations. Interaction between the models was performed based on a specially created methodology. The obtained results can be used in the design of a FGDS for the supports in the compressors of aircraft engines and power plants.
Rapid gas temperature measurement device for gas turbine engines with detection of pre-surge phenomena
Authors: Artyukhov A V , Babkin V I , Sukhinets Z A , Gulin A I 
Published: May 2021

Abstract
A differential system for measurement of gas temperature in gas turbine engines (GTE) using acoustic multi-vibrators was presented. Application of acoustic multi-vibrators improves the response time by three orders of magnitude compared to thermocouples. Combined use with a gas flow meter and a vibration sensor makes it possible to measure the low-frequency component of acoustic vibrations of flowing gases in a GTE’s combustion chamber. As an example, a calculation to determine the resonance frequency of a combustion chamber of a GTE was given.
Computational and experimental study of bird failure at different speeds of collision with a flexible plate
Authors: Shorr B F , Serebriakov N N , Mel’nikova G V , Siversky A S , Nikiforov V S 
Published: May 2021

Abstract
This article presents an experimental and computational study of bird collision with a flexible plate at different impact speeds. Tests were carried out with the aid of a pneumatic gun. The bird mass in the study was about 300 g, and the speed range was 49-75 m/s. The actual mechanical properties of the plate were determined with tensile tests of flat specimen-witness. A video recording and strain gauging were performed during the strike. Some frames of high speed video recording for the highest bird’s velocity c = 75 m/s are presented in the article to demonstrate the process of bird rupturing. Different models of the bird material were examined to compare computational and measured strains.
Improving methods for predicting defects based on vibrography
Authors: Panov V.A. , Zasenko T.V , Zyuzin D.A. , Makovetskii-Serebryakov D.B. 
Published: May 2021

Abstract
The article is devoted to the broadband vibrodiagnostics of jet engines. The material discusses the main causes that affect the level of vibration of the engine. Using the methods for controlling vibrations in a wide frequency band, an analysis was made of the criteria that cause defects and their manifestations in a wide frequency band of vibrations. The author has studied the effect of defects in parts and assembly units on vibration levels in a wide range. Based on the data obtained, it was found that the results allow to determine the bottlenecks of the gas turbine engine with accuracy to the details of the assembly units.
A novel detergent-based decellularization combined with carbodiimide crosslinking for improving anti-calcification of bioprosthetic heart valve
Authors: Luo Yu , Huang Shenyu , Ma Lie 
Published: May 2021

Abstract
Currently, valve replacement surgery is the only therapy for the end-stage valvular diseases because of the inability of regeneration for diseased heart valves. Bioprosthetic heart valves (BHVs), which are mainly derived from glutaraldehyde (GA) crosslinked porcine aortic heart valves or bovine pericardium, have been widely used in the last decades. However, it is inevitable that calcification and deterioration may occur within 10–15 years, which are still the main challenges for the BHVs in clinic. In this study, N-Lauroylsarcosine sodium salt (SLS) combined with N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) were utilized to decellularize and crosslink the heart valves instead of GA treatment. The obtained BHVs exhibited excellent extracellular matrix stability and mechanical properties, which were similar with GA treatment. Moreover, the obtained BHVs exhibited better in vitro biocompatibilities than GA treatment. After subcutaneous implantation for 30 d, the obtained BHVs showed mitigated immune response and reduced calcification compare with GA treatment. Therefore, all the above results indicated that the treatment of SLS-based decellularization combined with EDC/NHS crosslink should be a promising method to fabricate BHVs which can be used in clinic in future.
Evaluations of certain Catalan-Hankel Pfaffians via classical skew orthogonal polynomials
Authors: Shen Bo-Jian , Li Shi-Hao , Yu Guo-Fu 
Published: May 2021

Abstract
This paper is to evaluate certain Catalan-Hankel Pfaffians by the theory of skew orthogonal polynomials. Due to different kinds of hypergeometric orthogonal polynomials underlying the Askey scheme, we explicitly construct the classical skew orthogonal polynomials and then give different examples of Catalan-Hankel Pfaffians with continuous and q-moment sequences.
Liquid-liquid capillary rise
Authors: Rasuceanu I , Patrascu C , Magos I , Trandas N , Balan C 
Published: May 2021

Abstract
We study the dynamics of capillary rise of a liquid-liquid interface using two immiscible liquids. By adjusting the height of the less dense fluid column, we measure the rise of the ensemble in the tube. A theoretical model is proposed that captures the time dependence of the position of the interface. Particular attention is given to the dynamics of the oil-water interface. Different types of flow regimes are identified and compared with previous theoretical and experimental findings. The theoretical model was found to be in good qualitative agreement, even though the contact angles of the two interfaces do not remain constant during the elevation of the fluid.
The fracture of yield stress fluid jet in air and in viscous fluids
Authors: Broboana D , Ionescu C S , Balan C 
Published: May 2021

Abstract
One of the largest family of complex materials are represented by fluids with yield stress. In this category are included creams, pastes, greases, gels, in general materials which start to flow at a certain value of the imposed shear stress. A common characteristic of yield stress materials is the association of material instability with the onset of the fluid behavior. The present paper is concerned with the experimental investigations and numerical modeling of the dynamics of a yield stress fluid jet in air or immersed in viscous/viscoelastic liquids. A cream jet at constant flow rate is generated through a capillary with a syringe pump and the visualizations of its motion in a vessel filled with an immiscible fluid is performed with normal and high-speed cameras. One goal of the study is to test the capability of the VoF code to simulate the jetting phenomena, the rheology of the sample being modeled with the Carreau equation and the Herschel-Bulkley relation, respectively. The visualizations show the specific yield stress instabilities from jetting to coiling, buckling and fracture.
Human CO2 generation rates in small enclosures for different test cases
Authors: Georgescu Matei-Razvan , Nastase Illinca , Meslem Amina , Sandu Mihnea , Bode Florin 
Published: May 2021

Abstract
The present study deals with experimental measurements of CO2 generation rates, due to the human occupation of a full-scale experimental mock-up simulating the astronaut crew quarters aboard the International Space Station. The estimation of CO2 generation rates follows different methods as described in the literature. A single test subject in four different testing cases is considered, one at rest representing the baseline case and the other three cases at varying levels of physical activity or at rest but with a fixed breathing frequency requested from the human subject. The study results indicate that imposing a fixed breathing rate even while at rest increases the generation rate unpredictably. Following literature metabolic rate estimations, the latter two cases are equivalent to the subject being engaged in light or medium physical activities. The results are used to form recommendations for studies measuring human CO2 generation rates.
Environmental impact of bituminous mixtures produced with reclaimed asphalt pavement and rejuvenator
Authors: Forton A , Ciutina A , Marc P 
Published: May 2021

Abstract
The paper focuses on the investigation of the potential environmental impact related to the production of several types of bituminous mixtures containing different dosages of Reclaimed Asphalt Pavement (RAP) and Rejuvenator (Rej). All materials used in the presented study are specific and generally used for pavements in Romania. The RAP material was considered as an inert material and it was used in three dosages (25%, 50% and 75%). For the bituminous mixture produced with 50% RAP material, a rejuvenator consisting in a mixture of vegetal oils was used in three dosages of 0.2%, 0.4% and 0.6% by mass of RAP material. A total of seven types of bituminous mixtures were considered including one ‘conventional’ mixture produced with virgin materials and used as reference. The Environmental Impact Assessment was estimated for the production process of the analysed bituminous mixtures, by using Eco-indicator 99 method within SimaPro software. The results prove that the addition of RAP material leads to a net decrease of the energy use and environmental impact. Besides, when rejuvenators are used in this process, they can affect the energy balance and reduce the difference in environmental impact.