Aerospace technic and technology最新文献

{"title":"Оцінка впливу канавок у дифузорі на втрати повного тиску","authors":"Illia Yudin","doi":"10.32620/aktt.2023.4.04","DOIUrl":"https://doi.org/10.32620/aktt.2023.4.04","url":null,"abstract":"The subject of the study is the total pressure in the diffuser channel with passive control of the boundary layer. The object of this research is a diffuser channel with riblets. The mechanism of total pressure reduction due to the presence of longitudinal grooves on the streamlined surface is related to the strengthening of viscous forces acting in the transverse direction caused by them. These forces generate a relatively calm flow inside the riblets, which pushes out the turbulent flow, which causes surface friction, pushing it away from the surface. Thus, the process of generation and growth of elongated wall turbulent formations. In addition, in the presence of riblets, a change in the pressure field in the transverse direction is possible, as well as the creation of a quasi-two-dimensional flow in the immediate vicinity of the wall. In this work, the aim of research to investigate the influence of riblets on total pressure loss in the diffuser channel with the purpose of evaluating the influence of riblets on the change in the nature of the flow and the change in pressure, using numerical modeling. To study the nature of the flow in the diffuser channel, we resolved the following tasks: a diffuser channel was modeled with the following dimensions: length L=50 mm, hydraulic diameter at the inlet X=25 mm, hydraulic diameter at the outlet Y=40 mm, riblets diameter d=4 mm, number of riblets n =4 and n=8. The study was compared with a diffuser with the following dimensions: length L=50 mm, diameter at the inlet X=25 mm, diameter at the outlet Y=40 mm. To research the flow in the diffuser, the method of numerical experiment was chosen. An unstructured calculation grid was used in the diffuser for the research. The calculation of the turbulent gas flow was performed by numerically solving the averaged Navier-Stokes equations. During the numerical simulation of the flow, the Reynolds stress turbulent viscosity model will be used. As a result, using a diffuser with riblets increases the coefficient of hydraulic resistance compared to a smooth diffuser. The resistance reduction mechanism does not work due to the relatively short length of the diffuser and small longitudinal vortices of the riblets scale do not have time to form. There are pressure increasing instead of laminization of the flow and pressure decreasing. Scientific novelty - received new data on the effect of riblets in the diffuser channel on the total pressure loss coefficient. Practical significance - the obtained results can be used to control the boundary layer in diffuser channels (in diffuser compressor grates) to improve their characteristics.","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132774773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Огляд методів параметричного діагностування агрегатів гідравлічних і паливних систем літальних апаратів","authors":"Ihor Ohanian, Sergiy Yepifanov","doi":"10.32620/aktt.2023.4sup1.13","DOIUrl":"https://doi.org/10.32620/aktt.2023.4sup1.13","url":null,"abstract":"The subject of study in this article is the methods of parametric diagnostics of the technical condition of the units of an air vehicle's hydraulic and fuel systems, which make it possible to ensure the established reliability indicators of these systems throughout their entire life cycle. This work aims to analyze the existing literature on the methods of parametric diagnostics of hydraulic units, determine the basic requirements for the development of diagnostic methods for units of hydraulic, and fuel systems. The objective of the study is to classify the existing methods of parametric diagnostics, applied primarily to hydraulic systems, to analyze the advantages and disadvantages of the algorithms under consideration based on the requirements for diagnostic algorithms established by the authors, and to assess the possibility of effectively using these methodologies to diagnose the technical condition of a complex hydraulic distribution unit. The authors of this work formed the main requirements for the methods of diagnosing a hydraulic and fuel system's units based on the nature of the detected defects, the experience of using diagnostic algorithms, as well as the requirements of existing standards and scientific publications analysis. The authors developed a classification of parametric diagnostic algorithms to systematize existing works. This paper describes the main features and differences between diagnostic algorithms based on methods for identifying a mathematical model of an object and diagnostic algorithms in the space of measured parameters. Methods for forming diagnostic models of hydraulic units have been analyzed, such as the state-space model, the Hammerstein model, the Volterra model, the ARX model, and the matrix of influence coefficients. Established analysis of the application of defect identification algorithms such as a divided difference filter (DDF), a radial basis functions neural network RBF, and a cosine distance method. As a result, the advantages and disadvantages of the monitored diagnostic algorithms were identified and the main tasks for developing an algorithm for parametric diagnostics of the technical condition of a complex hydraulic distribution unit were formulated.","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124565033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Аналіз впливу місця впорскування води на характеристики турбореактивного двоконтурного двигуна з форсажною камерою згоряння","authors":"Yurii Ulitenko, Maryna Minenok, I. Kravchenko","doi":"10.32620/aktt.2023.4sup2.04","DOIUrl":"https://doi.org/10.32620/aktt.2023.4sup2.04","url":null,"abstract":"An important direction for the development of high-speed aircraft is the expansion of the range of operation of aircraft engines as part of their power plants. Currently, the range of operation of aircraft engines in terms of altitude and flight speed is limited by the ability of construction materials to withstand the temperature of the working body. Therefore, to expand the range of operation, it is necessary to either change the construction materials or use technologies that involve cooling the working body. The water injection system in a turbofan engine with an afterburner allows cooling of the working body without significant interference with the structural profile of the engine, which significantly saves design time and development cost. In addition, water injection has long been used for a short-term increase in engine thrust, which is an additional advantage of using this system. The choice of the place of water injection into the engine tract has a great influence on its characteristics and on the ability of the high-speed aircraft to perform the assigned tasks. Therefore, the design of the engine must take place with an understanding of the intended purpose of the high-speed aircraft. This article analyzes the influence of the place of water injection on the characteristics of a turbofan engine with an afterburner. I will consider water injection at the inlet to the fan and at the inlet to the high-pressure compressor. The influence of injection site and flight conditions on water consumption is shown. Operating conditions were found in which it is impossible to use a turbofan engine with an afterburner due to restrictions not related to the temperature of the working fluid. The results of calculations regarding the influence of the water injection site on the main thermodynamic parameters and traction characteristics of the engine are given. The application of the obtained results will increase the thermodynamic efficiency and extend the operating range of two-circuit turbofan engines with afterburners using modern materials. The results of this work will also make it possible to shorten the period of development of competitive engines for high-speed aircraft through a targeted search for their rational thermodynamic and structural-geometric outline.","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124813580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Дослідження впливу температури газу процесу холодного газодинамічного напилювання на адгезійну міцність нікелевмісних покриттів","authors":"O. Shorinov, Anatolii Dolmatov, Sergii Polyviany, K. Balushok","doi":"10.32620/aktt.2023.4sup2.11","DOIUrl":"https://doi.org/10.32620/aktt.2023.4sup2.11","url":null,"abstract":"The subject of the research is the influence of low-pressure cold spraying process parameters on the adhesive strength of the coatings. The goal is to ensure the maximum values of the adhesive strength of nickel-based coatings deposited by cold spraying by controlling the gas temperature at the nozzle inlet. The task is to investigate the effect of the temperature mode of the DYMET-405 machine on the adhesive strength of the coatings obtained from the Ni+Zn+Al2O3 powder mixture at constant other spraying parameters. Research methods. The experimental study of the adhesive strength was conducted on the tear using adhesive method in accordance with DSTU 2639-94. The metal-matrix composite powder mixture Ni+Zn+Al2O3 was used as powder material. VT3-1 titanium alloy was chosen as substrate material. Coatings were deposited using DYMET-405 low-pressure cold spraying machine. Temperature regulation at the nozzle inlet was performed by turning on the required temperature mode on the equipment control panel. Other spraying parameters remained constant during coating deposition process. The results. It was established that with an increase in the temperature of the gas in the nozzle, an increase in the adhesive strength of coatings is observed, on average from 9.5 MPa to 28.7 MPa. This can be explained by the fact that an increase in gas temperature leads to an increase in the velocity of the gas flow and, accordingly, of the powder particles in this flow. Higher particle impact velocity has a positive effect on the process of their deforming, filling of pores, densifying of coating layers, and finally increasing the adhesive and cohesive strength. The scientific novelty of the obtained results is that the dependence of the gas temperature at the nozzle inlet during low-pressure cold spraying on the adhesive strength of Ni+Zn+Al2O3 powder mixture coatings deposited on VT3-1 titanium alloy substrates was obtained. Conclusions. The practical value of the obtained results is that the obtained dependences of adhesive strength on gas temperature can be used for the development of cold spraying recommendations for the deposition of restorative coatings on parts made of titanium alloys, in particular in aircraft engines to eliminate operational defects.","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127241504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Характеристики повітряного гвинта квадрокоптера","authors":"Kateryna Balalaieva, Anton Balalaiev, Grygoriy Golembiyevskyy, A. Kovtun","doi":"10.32620/aktt.2023.4sup1.04","DOIUrl":"https://doi.org/10.32620/aktt.2023.4sup1.04","url":null,"abstract":"The subject of the study is the characteristics of the quadrocopter propeller. The object of the study is a two-blade propeller of a quadrocopter. The aim of this study was to evaluate the efficiency, acoustic characteristics of the propeller of a quadrocopter and optimize the angles of laying out carbon fiber with minimization of deflection. To achieve this goal, the following tasks were solved: simulation of the flow in a two-blade propeller of a quadrocopter in a given range of rotation frequencies; calculation of the efficiency of a two-blade propeller of a quadrocopter; calculation of the level of acoustic pressure of the studied propeller; and calculation of the deflection of a two-blade propeller of a quadrocopter at different angles of carbon laying out. The study of the flow in the propeller was carried out using the method of numerical experiment. The calculation for the deflection was carried out on the basis of the aerodynamic characteristics of the propeller using the method of a numerical experiment. The level of acoustic pressure L was estimated at 1 m from the source of acoustic radiation (screw). Results: the optimal mode of operation with a maximum efficiency is observed at a speed of 9000 rpm. and reaches a value of 0.853. At the minimum investigated speed of 3000 rpm. The propeller efficiency has the lowest value and is 0.638. With an increase in the speed of the rotor of the engine, the efficiency of the propeller gradually increases. With the increase of rotational speed from 9000 rpm. up to 10000 rpm. the efficiency decreases from 0.853 to 0.833. Estimation of the level of acoustic pressure of the studied two-bladed propeller showed that the rotation frequency had a significant effect on the level of acoustic pressure of the propeller. With an increase in rotational speed from 3000 rpm. up to 10000 rpm. propeller acoustic pressure-level increases from 56.62 dB to 90.57 dB. The calculation results showed that the deflection of the propeller blades under study depends on the laying angles of the carbon fiber layers. Blade deflection varies from 0.76 mm to 0.821 mm. The greatest deflection of the blades was achieved with the option of laying out layers of carbon fiber 0°/30°, the smallest - at angles of 0°/80°. The scientific novelty and practical significance of the conducted research is that new data on the characteristics of a two-blade quadrocopter propeller have been obtained. The data obtained will help create and optimize the parameters of a two-bladed quadrocopter propeller.","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127862567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Аналіз впливу мотогондоли на силу тяги вентиляторного контуру турбовентиляторної приставки","authors":"Roman Maiboroda","doi":"10.32620/aktt.2023.4.10","DOIUrl":"https://doi.org/10.32620/aktt.2023.4.10","url":null,"abstract":"The subject of this study is the interaction between the engine nacelle of a three-circuit turbojet engine and a turbofan attachment. The object of this research is a model of a cylindrical engine nacelle and a fan part of the impeller of a turbofan attachment. The aim of this study was to evaluate the influence of the engine nacelle on the thrust force of the fan circuit of a three-circuit turbojet engine, taking into account the influence of the operation of the turbofan attachment. Tasks: to simulate the flow around the engine nacelle with a turbofan attachment and without a turbofan attachment; calculate the thrust force of the turbofan attachment. The studies were carried out using the method of numerical experiment. The system of Navier-Stokes equations was closed by the turbulent viscosity model SST Gamma Theta Transitional No. 4. The results of the study showed that the reactive thrust of the fan circuit of the turbofan attachment increases by 0.87-6.15% when operating at an altitude of 0 km, 9 km, 11 km and the range of Mach numbers at the input from 0.2 to 0.5. When flowing around the engine nacelle without taking into account the influence of the turbofan attachment, it is characteristic that the velocity field at the inlet is uniform, except for the zone with a boundary layer near the surface of the engine nacelle. However, during operation of the turbofan attachment, the flow pattern changes radically and the thickness of the boundary layer decreases, and the flow in front of the fan is uneven. A characteristic feature of the turbofan attachment, which is associated with the heating of the intermediate housing between the turbine and fan housings, has a positive effect on reducing the thickness of the boundary layer, wall heating contributes to an increase in the stagnant flow velocity due to viscous forces. The presence of a boundary layer on the engine nacelle does not adversely affect the flow in the fan circuit of the turbofan attachment, and the fan of the turbofan attachment does not adversely affect the engine gas generator. The scientific novelty and practical significance of this work lies in obtaining new data on the effect of the engine nacelle on the thrust force of the fan circuit of a three-circuit turbojet engine, taking into account the influence of the operation of the turbofan attachment. The results obtained can be used to optimize the turbofan attachment of a three-circuit turbojet engine.","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"15 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113971229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Порівняння потужності критеріїв наявності тренду в часових рядах","authors":"V. Myrhorod, Iryna Hvozdeva","doi":"10.32620/aktt.2023.4sup2.07","DOIUrl":"https://doi.org/10.32620/aktt.2023.4sup2.07","url":null,"abstract":"The subject of research is methods, mathematical models, and methods of continuous analysis of a multidimensional set of output variables and state variables of power and energy installations built on the basis of gas turbine engines, which in general constitute time series. The purpose of this work is to establish the power of trend and randomness criteria by statistical modeling of time series with a linear trend and the use of known trend and randomness statistics to establish their empirical distributions and operational characteristics for comparing trend criteria by their power. The tasks faced by the developers were to determine the empirical distributions of known parametric and non-parametric trend statistics when applying the linear trend model in superposition with a random component, and set the level of errors of the first kind (false solution), with a given level of errors of the second kind (false anxiety). The methods that were used to achieve the established goal of the research: general methods of trend analysis, methods of applied statistics, and methods of conducting computer experiments. The results of the research provide a rationale for the approach to establishing the power of known criteria of trend and randomness. The limitation of the known methods of applied statistics is that it is theoretically only possible to refute the hypothesis regarding the randomness of the initial data at a certain level of significance, which determines the level of errors of the second kind (false alarms). Establishing the level of errors of the first kind (wrong decision) poses significant difficulties, because in the presence of a trend, the time series can no longer be stationary. But it is the statistical level of such errors that actually determines the strength of the criteria for the presence of a trend in the time series. The resolution of this contradiction is proposed by means of statistical modeling of time series with a linear trend and the use of well-known trend and randomness statistics to establish their empirical distributions and operational characteristics and to compare trend criteria according to their power. Statistical modeling was performed for a number of trend and randomness statistics, namely: the most common parametric statistics: correlation criterion and its modifications, Fisher's criterion, and Student's criterion; and non-parametric Wald-Wolfowitz criteria; Bartles; as well as the inversion criterion. According to the results of statistical modeling, it was established that the Student's criterion is the most powerful of the parametric criteria, and the inversion criterion is the most powerful of the non-parametric criteria. It is understood that such conclusions are valid when the assumptions regarding the initial statistical model of data generation in the form of a superposition of a linear trend and a random component as a sample from the general population of independent and normally distributed random ","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116010611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Тестова задача моделювання течії у ступені компресора Rotor 37","authors":"Andrii Duliepov, Yevhenii Hlobin, A. Kovtun, Mykhailo Khyzhniak, Kateryna Balalaieva","doi":"10.32620/aktt.2023.4.09","DOIUrl":"https://doi.org/10.32620/aktt.2023.4.09","url":null,"abstract":"The subject of the study is the dependence of the degree of pressure increase on the airflow in the impeller of the axial compressor degree. The object of study is the Rotor 37 axial compressor. The purpose of this study was to select a turbulent viscosity model when conducting a test task in the Rotor 37 compressor. To achieve this goal, the following tasks were solved: to create a three-dimensional model of the object under study; develop a grid model of the object under study; to simulate the flow in a certain range of air flow; to compare the data of numerical and physical experience; evaluate the flow visualization in the Rotor 37 axial compressor stage for all studied turbulent viscosity models. When studying the flow in the stage of the axial compressor Rotor 37, the numerical experiment method was used. The flow simulation was carried out by solving the system of Navier-Stokes equations, which was closed by the turbulent viscosity model. The study used seven turbulent viscosity models: k-ε, k-ε EARSM, SST, BSL, BSL Reynolds Stress, SSG Reynolds Stress, and QI Reynolds Stress. For simulation, a computational grid was built with the adaptation of the boundary layer. This study presents the results of a flow simulation test problem in the Rotor 37 compressor. The results of the study show that all the tested turbulent viscosity models can be used to simulate the flow in an axial compressor. However, the flow calculation with the SSG Reynolds Stress turbulent viscosity model has the smallest error. An analysis of the visualization of streamlines in the interblade channel of the Rotor 37 compressor showed that in all cases, the flow pattern with all turbulent viscosity models is similar. Some differences are observed when modeling the flow with the BSL Reynolds Stress and SST turbulence models. An important factor that should also be taken into account when modeling is the calculation time. In this case, the shortest calculation time was observed for simulation with SST model. Scientific novelty and practical significance is that new data were obtained when testing the following turbulent viscosity models: k-ε, k-ε EARSM, SST, BSL, BSL Reynolds Stress, SSG Reynolds Stress, QI Reynolds Stress. The results obtained made it possible to choose a turbulent viscosity model for further research.","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120993462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Методика оцінки залежності власних частот коливань лопаток газових турбін від анізотропії монокристалу","authors":"Yevhen Nemanezhyn, G. Lvov, Yuriy Torba","doi":"10.32620/aktt.2023.4sup2.06","DOIUrl":"https://doi.org/10.32620/aktt.2023.4sup2.06","url":null,"abstract":"The subject of study of this article is one of the key tasks that arises during the development and operation of aviation gas turbine engines, namely ensuring the strength of their parts. The turbine blade is one of the most heavily loaded parts of an aircraft engine. Therefore, at the stage of designing these blades, it is necessary to be able to identify and avoid possible resonance modes that appear during the flight cycle of an aircraft gas turbine engine. Such resonant oscillations of gas turbine blades can occur due to time-varying gas-dynamic forces from the action of the gas flow and are periodic in nature, as they are determined by the frequency of rotation of the rotor. In order to regulate the frequency characteristics of the blades to prevent dangerous resonant forms of oscillations that arise under the action of various harmonics of the exciting force during variable modes of operation of the aircraft engine, it is necessary to carry out a complex of various technological or structural changes. At the current stage, turbine blades of aircraft engines are manufactured by the method of single-crystal casting. As is known, single crystals have anisotropic properties, namely they manifest themselves as materials with the characteristics of cubic symmetry. A very urgent task is to investigate the effect of the anisotropy of the elastic characteristics of monocrystalline blades on their natural frequencies and forms of oscillations. In this research, the authors developed a method for determining the elastic characteristics of a single crystal, namely Young's modulus of elasticity, Poisson's ratio and pure shear modulus, which is based on available experimental data for typical heat-resistant alloys. With the help of finite element analysis on the example of a typical model of a cooled blade of a gas turbine, its modal analysis was carried out and its resonance diagram was constructed. The trend of changing the natural frequencies and forms of blade oscillations when the elastic constants of the single crystal change due to the rotation of the crystallographic system of directions was also investigated. The three-dimensional model of the blade was built using the capabilities of the NX graphics complex, all calculations were performed in the Maple computing complex, and the capabilities of the ANSYS software complex were used for finite element analysis.","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129057140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of aerodynamic noise of quadrotor type aerotaxi","authors":"P. Lukianov, Oleg Dusheba","doi":"10.32620/aktt.2023.4.05","DOIUrl":"https://doi.org/10.32620/aktt.2023.4.05","url":null,"abstract":"The subject of this work is a study of the current state of modeling the flow around the blades of quadcopters, models of aerodynamic sound generation, formulation, and numerical solution of the problem of generation of rotation noise by the blades of a quadrotor type aerotaxi. The models describing the flow field around the quadrotor blades include the model of nonlinear vortices in lattices, the Reynolds-averaged Navier-Stokes equation (RANS, URANS), the large eddy simulation method (LES), and the direct numerical simulation (DNS) of the system of aerodynamic equations. This paper analyzes the main noise models of different types of aerodynamic origin.  Gutin’s model  is used to describe the noise of the quadrotor rotation, and the Ffowcs -Williams-Hawkings equation  in the formulation of Farassat is used to model the noise taking into account various sound sources. However, these approaches have certain drawbacks that limit their application. The following paper uses a modern approach to modeling noise of aerodynamic origin based on the three-dimensional unsteady equation of sound propagation from a thin blade in the potential approximation, previously proposed by one of the authors of the work. Using this approach, a numerical calculation of the problem of sound generation (rotational noise) of the aerodynamic origin of a quadrotor type aerotaxi was performed. The purpose of the study. Despite the approaches described above, there is a problem associated with achieving an acceptable noise level, i.e. its further reduction. To solve this problem, there is a need to use more accurate models that will allow research on reducing air taxi noise. Tasks of the study. In this regard, the task of modeling noise of aerodynamic origin was set and solved using a refined model of the sound generated by the interaction of the flow and air taxi blades. Research methods are based on the construction and use of a mathematical model for the generation of rotation sound generated by the joint operation of aerotaxi rotors. On this basis, the calculations of the near and far sound fields were performed. A new model for calculating the long-range sound field of a quadrotor type aerotaxi is proposed, which considers the mutual formation of the resulting sound field from the joint operation of 4 propellers. The pressure coefficient and the sound pressure level in the distant sound field were calculated, and the frequency filling of the spectrum of the generated sound wave was investigated. Results and Conclusions. Numerical calculations of the problem of aerotaxi rotation noise generation showed that the maximum pressure level in the generated waves is in the immediate vicinity of the location of the quadrotor screws. However, the maximum value of the pressure level depends on the parameters of the problem, which vary: the thickness of the blade and the speed of the horizontal flight of the aerotaxi. As one moves away from the screws, the local maxima disappear and ","PeriodicalId":418062,"journal":{"name":"Aerospace technic and technology","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127125070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}