Pub Date : 2023-12-02DOI: 10.13111/2066-8201.2023.15.4.9
Catalin Cucu, Cristina Pupaza, Bart Janssens, Mihai MIHAILA-ANDRES
A study of the air behavior in the near-wake region of the NACA0012 airfoil infinite wing model at low Reynolds numbers was conducted. The study consisted of comparing the results obtained from experiments with those from numerical simulations. The numerical results of the velocity profiles in the near-wake region showed good agreement with those provided by the PIV system for most of the simulations and those in the literature. In addition, boundary layer separation and reattachment forming a laminar separation bubble along the airfoil was captured using simulations in Ansys Fluent and compared with a literature database to better confirm the simulation results. The UAVs have a complex cross-section shape of the fuselage. The second part of this paper explores the aerodynamic consequences of its shape, at the operational flight ceiling, in a comparative approach for three different fuselage designs.
{"title":"Study of the influence of turbulent flows on the aerodynamic performance of fixed-wing aircraft type UAV MALE","authors":"Catalin Cucu, Cristina Pupaza, Bart Janssens, Mihai MIHAILA-ANDRES","doi":"10.13111/2066-8201.2023.15.4.9","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.9","url":null,"abstract":"A study of the air behavior in the near-wake region of the NACA0012 airfoil infinite wing model at low Reynolds numbers was conducted. The study consisted of comparing the results obtained from experiments with those from numerical simulations. The numerical results of the velocity profiles in the near-wake region showed good agreement with those provided by the PIV system for most of the simulations and those in the literature. In addition, boundary layer separation and reattachment forming a laminar separation bubble along the airfoil was captured using simulations in Ansys Fluent and compared with a literature database to better confirm the simulation results. The UAVs have a complex cross-section shape of the fuselage. The second part of this paper explores the aerodynamic consequences of its shape, at the operational flight ceiling, in a comparative approach for three different fuselage designs.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606483","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}
Pub Date : 2023-12-02DOI: 10.13111/2066-8201.2023.15.4.2
I. Andrei, G. Stroe, S. Berbente, G. Stoica, N. Crișan, D. Prisecaru, Anca Greculescu, Emil Costea, Ionel Popescu, Cristian Stoica, Octavian Ioan Filipescu
This paper presents a study dedicated to the development of Digital and Smart Tools, based on solved applications of design engineering and reverse engineering. This approach is justified by the fact as well as the need for preparations prior to Composite Additive Manufacturing. Future integration of Digital Smart Tools with Composite Additive Manufacturing will significantly contribute to the efficient and effective support of the green economy, the active, responsible, safe and resilient protection of environment, life and climate. The research involved in this paper contributes to develop Digital and Smart Tools Applications, intended for integrated digital design, development, manufacturing and further predictive maintenance and services, based on robotic systems, extended automatic control, Artificial Intelligence and Machine Learning, including Mathematical Modeling and Numerical Simulations for Performance Prediction at Design Regime and Off-Design Regimes for jet engines, with the best capabilities to generate and integrate improvements, optimizations and potential innovative solutions. This paper presents significant applications of design, concept engineering development and reverse engineering design, as: 1/ the design of a transonic axial compressor rotor blade, 2/ the design of a swept axial compressor rotor, 3/ concept design engineering developments in case of a swept fan rotor blade, 4/ concept design developments and reverse engineering in case of a HP axial compressor rotor blade, part of Spey 512-14 DW turbofan engine, 5/ reverse engineering design of a Cessna 182 Skylane N223IF light aircraft wheel cover. In line with Europe´s vision for sustainable aviation, this research study and INCAS´ TGA Project "Technological Development Platform for "Green" Technologies in Aviation and Ecological Manufacturing with Superior Added Value; TGA - Technologies for Green Aviation" will significantly contribute to the Green Deal, as a production center using "Green" Technologies in aviation and ecological manufacturing, as well as collaborative developer of Digital and Smart Tools for Composite Additive Manufacturing.
{"title":"Applications of design and reverse engineering for the development of digital and smart tools for composite additive manufacturing","authors":"I. Andrei, G. Stroe, S. Berbente, G. Stoica, N. Crișan, D. Prisecaru, Anca Greculescu, Emil Costea, Ionel Popescu, Cristian Stoica, Octavian Ioan Filipescu","doi":"10.13111/2066-8201.2023.15.4.2","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.2","url":null,"abstract":"This paper presents a study dedicated to the development of Digital and Smart Tools, based on solved applications of design engineering and reverse engineering. This approach is justified by the fact as well as the need for preparations prior to Composite Additive Manufacturing. Future integration of Digital Smart Tools with Composite Additive Manufacturing will significantly contribute to the efficient and effective support of the green economy, the active, responsible, safe and resilient protection of environment, life and climate. The research involved in this paper contributes to develop Digital and Smart Tools Applications, intended for integrated digital design, development, manufacturing and further predictive maintenance and services, based on robotic systems, extended automatic control, Artificial Intelligence and Machine Learning, including Mathematical Modeling and Numerical Simulations for Performance Prediction at Design Regime and Off-Design Regimes for jet engines, with the best capabilities to generate and integrate improvements, optimizations and potential innovative solutions. This paper presents significant applications of design, concept engineering development and reverse engineering design, as: 1/ the design of a transonic axial compressor rotor blade, 2/ the design of a swept axial compressor rotor, 3/ concept design engineering developments in case of a swept fan rotor blade, 4/ concept design developments and reverse engineering in case of a HP axial compressor rotor blade, part of Spey 512-14 DW turbofan engine, 5/ reverse engineering design of a Cessna 182 Skylane N223IF light aircraft wheel cover. In line with Europe´s vision for sustainable aviation, this research study and INCAS´ TGA Project \"Technological Development Platform for \"Green\" Technologies in Aviation and Ecological Manufacturing with Superior Added Value; TGA - Technologies for Green Aviation\" will significantly contribute to the Green Deal, as a production center using \"Green\" Technologies in aviation and ecological manufacturing, as well as collaborative developer of Digital and Smart Tools for Composite Additive Manufacturing.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606569","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}
Pub Date : 2023-12-02DOI: 10.13111/2066-8201.2023.15.4.13
Alexandru Mereu, D. Isvoranu
This paper presents the authors’ most recent research regarding the feasibility of cooling a 1 kN scaled-down experimental rocket engine, running on gaseous oxygen and gaseous methane, for a ground test. The cooling segment of a rocket engine has always been a delicate problem, increasing the development time and costs of development. Since a series of problems can occur during the first ignition of a rocket engine prototype, removing as many potential issues from the initial test, such as using liquid methane for the cooling system, could result in a more stable experiment. Using water as the cooling agent can contribute to a more accelerated TRL increase of the engine’s subcomponents while reducing the risks taken for a whole assembly test. Thus, the combustion chamber, nozzle, and injector can be tested separately from the final cooling method, which can be added subsequently. In the present work, both a steady and transient CFD combustion simulation of a multicomponent compound, consisting of gaseous oxygen and gaseous methane was conducted in the combustion chamber of a small-scale rocket engine. The simulation is based on PDF-flamelet approach for the oxygen and methane combustion, along with real gas equations for the cooling agent.
{"title":"Joint design and simulation of GOX-GCH4 combustion and cooling in an experimental water-cooled subscale rocket engine","authors":"Alexandru Mereu, D. Isvoranu","doi":"10.13111/2066-8201.2023.15.4.13","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.13","url":null,"abstract":"This paper presents the authors’ most recent research regarding the feasibility of cooling a 1 kN scaled-down experimental rocket engine, running on gaseous oxygen and gaseous methane, for a ground test. The cooling segment of a rocket engine has always been a delicate problem, increasing the development time and costs of development. Since a series of problems can occur during the first ignition of a rocket engine prototype, removing as many potential issues from the initial test, such as using liquid methane for the cooling system, could result in a more stable experiment. Using water as the cooling agent can contribute to a more accelerated TRL increase of the engine’s subcomponents while reducing the risks taken for a whole assembly test. Thus, the combustion chamber, nozzle, and injector can be tested separately from the final cooling method, which can be added subsequently. In the present work, both a steady and transient CFD combustion simulation of a multicomponent compound, consisting of gaseous oxygen and gaseous methane was conducted in the combustion chamber of a small-scale rocket engine. The simulation is based on PDF-flamelet approach for the oxygen and methane combustion, along with real gas equations for the cooling agent.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606993","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}
Pub Date : 2023-09-04DOI: 10.13111/2066-8201.2023.15.3.5
Ș. Mustață, Cristian Vidan, C. Larco, Carmen-Ioana Bogliș, Bianca-Gabriela Antofie
Given the advantages in terms of weight, size and cost and because it can withstand severe shocks and temperature changes, the MEMS/NEMS sensors are widely used in the aerospace domain. This paper presents a brief history of the scientists who made reference to micro and nano technologies for the first time, followed by a synthesis of the leading technologies used in the manufacture of microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS) intensively used in aerospace industry. After reviewing the latest technologies used in the manufacture of MEMS/NEMS sensors, the paper continues with predicting the current state regarding the development of NEMS and MEMS, respectively.
{"title":"Overview of the technologies used in the fabrication of MEMS/NEMS actuators for space applications","authors":"Ș. Mustață, Cristian Vidan, C. Larco, Carmen-Ioana Bogliș, Bianca-Gabriela Antofie","doi":"10.13111/2066-8201.2023.15.3.5","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.3.5","url":null,"abstract":"Given the advantages in terms of weight, size and cost and because it can withstand severe shocks and temperature changes, the MEMS/NEMS sensors are widely used in the aerospace domain. This paper presents a brief history of the scientists who made reference to micro and nano technologies for the first time, followed by a synthesis of the leading technologies used in the manufacture of microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS) intensively used in aerospace industry. After reviewing the latest technologies used in the manufacture of MEMS/NEMS sensors, the paper continues with predicting the current state regarding the development of NEMS and MEMS, respectively.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45004173","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}
Pub Date : 2023-09-04DOI: 10.13111/2066-8201.2023.15.3.2
Ionuț Bunescu, Stefan Bogos, Teodor-Viorel Chelaru, Mihai-Vlăduţ Hothazie, Mihai-Victor Pricop
This paper presents a coherent approach to evaluate the roll damping derivatives for the standard Basic Finner Model. The study compares and analyses the results obtained through a range of techniques, including experimental testing, numerical simulations and semi-empirical models. The study aims to evaluate the reliability and accuracy of these methods and to identify the factors that contribute to their sensitivity. The paper concludes by summarizing the findings of the study and discussing the implications of the results for the design and operation of rockets. The experimental and numerical analysis used in this study provides a robust and comprehensive evaluation of the roll damping coefficient.
{"title":"Coherent solutions to roll damping derivatives evaluation for a generic rocket model","authors":"Ionuț Bunescu, Stefan Bogos, Teodor-Viorel Chelaru, Mihai-Vlăduţ Hothazie, Mihai-Victor Pricop","doi":"10.13111/2066-8201.2023.15.3.2","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.3.2","url":null,"abstract":"This paper presents a coherent approach to evaluate the roll damping derivatives for the standard Basic Finner Model. The study compares and analyses the results obtained through a range of techniques, including experimental testing, numerical simulations and semi-empirical models. The study aims to evaluate the reliability and accuracy of these methods and to identify the factors that contribute to their sensitivity. The paper concludes by summarizing the findings of the study and discussing the implications of the results for the design and operation of rockets. The experimental and numerical analysis used in this study provides a robust and comprehensive evaluation of the roll damping coefficient.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46778144","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}
Pub Date : 2023-09-04DOI: 10.13111/2066-8201.2023.15.3.4
Marshall C. Mccray, P. Cizmas
The critical Reynolds number for dispersed bubbly two-phase flows, gas in liquid, was experimentally investigated. In this experiment, the gas was air and the liquid was water. Water flowed upward through a vertical, translucent pipe, and air was introduced into the water prior to the test section by means of a basswood microbubbler. Dye was injected into the water to indicate when the flow transitioned from laminar to turbulent. Mixtures with gas volume fractions up to 10% were tested, and the Reynolds numbers for which the flow transitioned from laminar to turbulent were recorded. The data showed that the critical Reynolds number fell to roughly one-half of its original single-phase liquid value once the gas volume fractions exceeded 0.1%. These results indicate that the presence of even small amounts of bubbles causes pre-mature transition to turbulence.
{"title":"Experimental investigation of the critical Reynolds number for bubbly two-phase flow","authors":"Marshall C. Mccray, P. Cizmas","doi":"10.13111/2066-8201.2023.15.3.4","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.3.4","url":null,"abstract":"The critical Reynolds number for dispersed bubbly two-phase flows, gas in liquid, was experimentally investigated. In this experiment, the gas was air and the liquid was water. Water flowed upward through a vertical, translucent pipe, and air was introduced into the water prior to the test\u0000section by means of a basswood microbubbler. Dye was injected into the water to indicate when the flow transitioned from laminar to turbulent. Mixtures with gas volume fractions up to 10% were tested, and the Reynolds numbers for which the flow transitioned from laminar to turbulent were recorded.\u0000The data showed that the critical Reynolds number fell to roughly one-half of its original single-phase liquid value once the gas volume fractions exceeded 0.1%. These results indicate that the presence of even small amounts of bubbles causes pre-mature transition to turbulence.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41653504","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}
Pub Date : 2023-09-04DOI: 10.13111/2066-8201.2023.15.3.9
S. Tolentino
Experimental studies for supersonic airflow in different supersonic nozzle geometries are recurrent, and the turbulence of the flow can be reproduced with the CFD tool by applying the RANS model and suitable turbulence models. The objective of this investigation is to carry out a comparative analysis of 2D numerical simulation curves for viscous flow with averaged data against equation curves for quasi-one-dimensional isentropic flow, for three experimental supersonic nozzle geometries that are used in the laboratory, for the flow condition without the presence of shock waves in the divergent. For the numerical simulations, three computational domains were discretized with structured grids, the Spalart-Allmaras turbulence model was used, and the Sutherland's law equation was used for the viscosity as a function of temperature. The results of the curve trajectories for Mach number, pressure and temperature obtained with averaged data from the 2D simulations are close to the curves of the analytical and empirical equations for isentropic flow. It is concluded that the numerical error of the total temperature for the planar nozzle with 𝛼𝛼 = 11.01° and NPR = 8.945 reports 0.008%; for the conical nozzle with 𝛼𝛼 = 15° and NPR = 14.925 it reports 1%; and, finally, for the conical nozzle with 𝛼𝛼 = 4.783° and NPR = 7, it reports 0.04%.
{"title":"Comparative analysis of 2D simulations and isentropic equations for compressible flow in experimental nozzles","authors":"S. Tolentino","doi":"10.13111/2066-8201.2023.15.3.9","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.3.9","url":null,"abstract":"Experimental studies for supersonic airflow in different supersonic nozzle geometries are recurrent, and the turbulence of the flow can be reproduced with the CFD tool by applying the RANS model and suitable turbulence models. The objective of this investigation is to carry out a comparative analysis of 2D numerical simulation curves for viscous flow with averaged data against equation curves for quasi-one-dimensional isentropic flow, for three experimental supersonic nozzle geometries that are used in the laboratory, for the flow condition without the presence of shock waves in the divergent. For the numerical simulations, three computational domains were discretized with structured grids, the\u0000Spalart-Allmaras turbulence model was used, and the Sutherland's law equation was used for the viscosity as a function of temperature. The results of the curve trajectories for Mach number, pressure and temperature obtained with averaged data from the 2D simulations are close to the curves of the analytical and empirical equations for isentropic flow. It is concluded that the numerical error of the total temperature for the planar nozzle with 𝛼𝛼 = 11.01° and NPR = 8.945 reports 0.008%; for the conical nozzle with 𝛼𝛼 = 15° and NPR = 14.925 it reports 1%; and, finally, for the conical nozzle with 𝛼𝛼 = 4.783° and NPR = 7, it reports 0.04%.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47063165","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}
Pub Date : 2023-09-04DOI: 10.13111/2066-8201.2023.15.3.10
P. UMAMAHESWAR RAO, D. VIJAY PRAVEEN
This work is an attempt to select the optimum process parameters for friction stir welding of similar AA6061 aluminum alloy based on multiple criteria decision-making approach. The friction stir welding experiments have been conducted according to the orthogonal L9 array and the chosen input parameters are tool rotational speed, feed, and tilt angle. The responses measured are tensile strength, hardness, and % of elongation of welded joint. The multi-criteria decision-making technique namely multi-objective optimization based on the ratio analysis (MOORA) is used to find the optimum process parameters combination. The optimum conditions are tool rotational speed of 1120 rpm, feed of 30 mm/rev and tilt angle at 1 o.
{"title":"Multi-objective optimization of process parameters during friction stir welding of similar AA6061 using MOORA","authors":"P. UMAMAHESWAR RAO, D. VIJAY PRAVEEN","doi":"10.13111/2066-8201.2023.15.3.10","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.3.10","url":null,"abstract":"This work is an attempt to select the optimum process parameters for friction stir welding of similar AA6061 aluminum alloy based on multiple criteria decision-making approach. The friction stir welding experiments have been conducted according to the orthogonal L9 array and the chosen input parameters are tool rotational speed, feed, and tilt angle. The responses measured are tensile strength, hardness, and % of elongation of welded joint. The multi-criteria decision-making technique namely multi-objective optimization based on the ratio analysis (MOORA) is used to find the optimum process parameters combination. The optimum conditions are tool rotational speed of 1120 rpm, feed of 30 mm/rev and tilt angle at 1 o.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135404181","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}
Pub Date : 2023-09-04DOI: 10.13111/2066-8201.2023.15.3.1
Ahmed ABDALLAH ELHIRTSI, T. Zebbiche
In this study, a method for designing supersonic nozzles with axisymmetric plugs at high temperature has been proposed. The approach is based on the theory of Prandtl-Mayer expansion at high temperatures using the method of characteristics. For this purpose, a code in FORTRAN language was developed in order to obtain the nozzle design. Once the latter was obtained, we were interested in the evolution of the thermodynamic parameters of the flow such as pressure, temperature, and Mach number. The results achieved were confronted with those obtained for a perfect gas model. Regarding the design parameters (length, section ratio, thrust coefficient and mass coefficient), we found that the PG model gives very satisfactory results for values of 𝑀𝑀 and 𝑇𝑇0 below 2.00 and 1000 𝐾𝐾, respectively. As 𝑀𝑀𝐸𝐸 and 𝑇𝑇0 increase, this affects performance, requiring the use of our HT model to correct the calculations. In order to minimize the weight of this nozzle, this research is investigating the truncation of the Plug nozzle to increase its performances. All calculations were performed for air.
{"title":"Design and performance evaluation of a high temperature axisymmetric plug nozzle","authors":"Ahmed ABDALLAH ELHIRTSI, T. Zebbiche","doi":"10.13111/2066-8201.2023.15.3.1","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.3.1","url":null,"abstract":"In this study, a method for designing supersonic nozzles with axisymmetric plugs at high temperature has been proposed. The approach is based on the theory of Prandtl-Mayer expansion at high temperatures using the method of characteristics. For this purpose, a code in FORTRAN language was developed in order to obtain the nozzle design. Once the latter was obtained, we were interested in the evolution of the thermodynamic parameters of the flow such as pressure, temperature, and Mach number. The results achieved were confronted with those obtained for a perfect gas model. Regarding the design parameters (length, section ratio, thrust coefficient and mass coefficient), we found that the PG model gives very satisfactory results for values of 𝑀𝑀 and 𝑇𝑇0 below 2.00 and 1000 𝐾𝐾, respectively.\u0000As 𝑀𝑀𝐸𝐸 and 𝑇𝑇0 increase, this affects performance, requiring the use of our HT model to correct the calculations. In order to minimize the weight of this nozzle, this research is investigating the truncation of the Plug nozzle to increase its performances. All calculations were performed for air.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46586929","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}
Pub Date : 2023-09-04DOI: 10.13111/2066-8201.2023.15.3.6
E. Prisăcariu, T. Prisecaru
The present article investigates the accuracy of measurements regarding the velocity profile of a turbulent jet. The measurements are obtained by applying image processing techniques to schlieren methods. The schlieren methods described here are relatively new, having been patented and used for the first time in the last few years. Generally, SIV methods applied to turbulent flows result in unrelatable/ unrelated data, given the path-integrated nature of the flow. The global measurement errors and ways to reduce them are also discussed.
{"title":"Schlieren image velocimetry methods for a round, hot, turbulent air-jet","authors":"E. Prisăcariu, T. Prisecaru","doi":"10.13111/2066-8201.2023.15.3.6","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.3.6","url":null,"abstract":"The present article investigates the accuracy of measurements regarding the velocity profile of a turbulent jet. The measurements are obtained by applying image processing techniques to schlieren methods. The schlieren methods described here are relatively new, having been patented and used for the first time in the last few years. Generally, SIV methods applied to turbulent flows result in unrelatable/ unrelated data, given the path-integrated nature of the flow. The global measurement errors and ways to reduce them are also discussed.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44346452","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：