Pub Date : 2023-06-06DOI: 10.24937/2542-2324-2023-2-404-91-96
D.V. Golovachev, M. Kicha, D. S. Malovik
Object and purpose of research. The object of scientific work is the methods of air purification of surface ships and Navy vessels from toxic substances, radioactive dust, and biological damaging agents. Materials and methods. Based on the analysis of technical documentation for the used and promising equipment of chemical ventilation. Main results. The optimal composition and main tactical and technical characteristics of a promising installation of chemical ventilation. Conclusion. An acceptable level of automation, controllability and maintainability for the Navy was obtained when using the aggregated anti-chemical ventilation unit.
{"title":"Air purification in ship spaces by means of gas venting system","authors":"D.V. Golovachev, M. Kicha, D. S. Malovik","doi":"10.24937/2542-2324-2023-2-404-91-96","DOIUrl":"https://doi.org/10.24937/2542-2324-2023-2-404-91-96","url":null,"abstract":"Object and purpose of research. The object of scientific work is the methods of air purification of surface ships and Navy vessels from toxic substances, radioactive dust, and biological damaging agents. Materials and methods. Based on the analysis of technical documentation for the used and promising equipment of chemical ventilation. Main results. The optimal composition and main tactical and technical characteristics of a promising installation of chemical ventilation. Conclusion. An acceptable level of automation, controllability and maintainability for the Navy was obtained when using the aggregated anti-chemical ventilation unit.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46358705","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 : 2023-06-06DOI: 10.24937/2542-2324-2023-2-404-117-128
A. Martynov, V. Samsygin, D. Sokolov
Object and purpose of research. The object of work is an autonomous offshore power plant designed to provide energy to the underwater docking station. The aim is to develop the basics of the methodology for calculating the electric generator of an autonomous offshore power plant, placed in a capsule with a conical nozzle – a diffuser. Materials and methods. The study was conducted on the basis of analytical methods for calculating electromechanical systems designed for energy supply of resident underwater robots and robotic complexes. Main results. The basics of the methodology for calculating the basic parameters of a synchronous generator of ring structure with magnetoelectric excitation, which converts the energy of the sea current into electrical energy transmitted to the underwater dock station for charging batteries, have been developed. The developed system of power supply of the underwater docking station is protected by a patent of the Russian Federation. Conclusion. The results of the development and research expand the possibilities of choosing the optimal option for the energy supply system of underwater docking stations and contribute to the acceleration of the process of their implementation in practice.
{"title":"On the issue of calculation of an autonomous marine power plant for energy supply of an underwater docking station","authors":"A. Martynov, V. Samsygin, D. Sokolov","doi":"10.24937/2542-2324-2023-2-404-117-128","DOIUrl":"https://doi.org/10.24937/2542-2324-2023-2-404-117-128","url":null,"abstract":"Object and purpose of research. The object of work is an autonomous offshore power plant designed to provide energy to the underwater docking station. The aim is to develop the basics of the methodology for calculating the electric generator of an autonomous offshore power plant, placed in a capsule with a conical nozzle – a diffuser. Materials and methods. The study was conducted on the basis of analytical methods for calculating electromechanical systems designed for energy supply of resident underwater robots and robotic complexes. Main results. The basics of the methodology for calculating the basic parameters of a synchronous generator of ring structure with magnetoelectric excitation, which converts the energy of the sea current into electrical energy transmitted to the underwater dock station for charging batteries, have been developed. The developed system of power supply of the underwater docking station is protected by a patent of the Russian Federation. Conclusion. The results of the development and research expand the possibilities of choosing the optimal option for the energy supply system of underwater docking stations and contribute to the acceleration of the process of their implementation in practice.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43650414","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 : 2023-06-06DOI: 10.24937/2542-2324-2023-2-404-50-57
Y. Yegorov, P. Ivanov, N. Marinich
Object and purpose of research. This paper discusses propeller model. The purpose of the study was to understand the effect of hydrodynamic load on the propeller upon its high-frequency non-cavitation noise radiation (edge noise). Materials and methods. Comparative analysis of Russian and foreign methods for assignment of edge noise norms. Edge noise measurements for a series of propeller models with different hydrodynamic load. Main results. The study yielded certain theoretical hints suggesting the effect of hydrodynamic load (as non-dimensional thrust coefficient Kt) upon edge noise. Experimental studies performed in this work have confirmed that this approach is valid for propeller models. Conclusion. Model tests have confirmed that edge noise depends on hydrodynamic load on the propeller (i.e. its thrust coefficient), as well as indicated tentative Kt range optimal for propeller noise mitigation.
{"title":"Edge noise vs hydrodynamic load on propeller model","authors":"Y. Yegorov, P. Ivanov, N. Marinich","doi":"10.24937/2542-2324-2023-2-404-50-57","DOIUrl":"https://doi.org/10.24937/2542-2324-2023-2-404-50-57","url":null,"abstract":"Object and purpose of research. This paper discusses propeller model. The purpose of the study was to understand the effect of hydrodynamic load on the propeller upon its high-frequency non-cavitation noise radiation (edge noise). Materials and methods. Comparative analysis of Russian and foreign methods for assignment of edge noise norms. Edge noise measurements for a series of propeller models with different hydrodynamic load. Main results. The study yielded certain theoretical hints suggesting the effect of hydrodynamic load (as non-dimensional thrust coefficient Kt) upon edge noise. Experimental studies performed in this work have confirmed that this approach is valid for propeller models. Conclusion. Model tests have confirmed that edge noise depends on hydrodynamic load on the propeller (i.e. its thrust coefficient), as well as indicated tentative Kt range optimal for propeller noise mitigation.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49157356","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 : 2023-06-06DOI: 10.24937/2542-2324-2023-2-404-154-157
A. Andreev, I. A. Shikhov
Object and purpose of research. Radar signatures of floating off-board decoys used by foreign navies for eluding anti-ship missiles of at sea are estimated. Materials and methods. Analysis of existing floating radar decoys are based on reviews of leading foreign experts. Signatures of these decoys at sea were calculated using a four-beam model of electromagnetic wave scattering on the underlying surface developed at KSRC. Main results. Quantitative assessments of floating decoy detection ranges by typical anti-ship missile radar seekers are made. Conclusion. The investigations showed that flying radar balloons are more effective in seduction of anti-ship missiles.
{"title":"Floating off-board radar decoys: stealth at sea","authors":"A. Andreev, I. A. Shikhov","doi":"10.24937/2542-2324-2023-2-404-154-157","DOIUrl":"https://doi.org/10.24937/2542-2324-2023-2-404-154-157","url":null,"abstract":"Object and purpose of research. Radar signatures of floating off-board decoys used by foreign navies for eluding anti-ship missiles of at sea are estimated. Materials and methods. Analysis of existing floating radar decoys are based on reviews of leading foreign experts. Signatures of these decoys at sea were calculated using a four-beam model of electromagnetic wave scattering on the underlying surface developed at KSRC. Main results. Quantitative assessments of floating decoy detection ranges by typical anti-ship missile radar seekers are made. Conclusion. The investigations showed that flying radar balloons are more effective in seduction of anti-ship missiles.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42468735","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 : 2023-06-06DOI: 10.24937/2542-2324-2023-2-404-158-164
S. Zenchenko
Object and purpose of research. The object of investigation is specific temperatures at the water/air interface (skin layer of water). The purpose is to study the interrelation of dynamics in humidity variations of surface atmospheric layer and particulars of the media interface. Subject matter and methods. Infrared thermal imagers are employed with monitoring of the parameters of atmospheric layer adjacent to ocean surface using a multi-channel thermal hygrometer and contact temperature sensors placed in water and near-water air layer. Laboratory rigs of different scales simulating various levels of external factors and an open water basin were used. Main results. Consistent analysis is done regarding phase-wise measurement of skin water layer characteristics, specific structure of temperature field in IR band of spectrum under laboratory and large-scale conditions, variations of humidity content at different state of skin water layer in the process of interaction between two media. Measurements of the radiation fog of different scales are taken, which possibly forms the false and real horizons being one of the interferences for transmission of IR radiation to recording channels. Parameters and specific manifestation of this interference are measured. Conclusion. Based on the analysis and experiments it is confirmed that there are abnormal localizations of humidity content of different scales, which produce radiation temperature variations.
{"title":"Generation of interference in the surface layer at horizontal sounding of sea surface by infrared sight channels and devices","authors":"S. Zenchenko","doi":"10.24937/2542-2324-2023-2-404-158-164","DOIUrl":"https://doi.org/10.24937/2542-2324-2023-2-404-158-164","url":null,"abstract":"Object and purpose of research. The object of investigation is specific temperatures at the water/air interface (skin layer of water). The purpose is to study the interrelation of dynamics in humidity variations of surface atmospheric layer and particulars of the media interface. Subject matter and methods. Infrared thermal imagers are employed with monitoring of the parameters of atmospheric layer adjacent to ocean surface using a multi-channel thermal hygrometer and contact temperature sensors placed in water and near-water air layer. Laboratory rigs of different scales simulating various levels of external factors and an open water basin were used. Main results. Consistent analysis is done regarding phase-wise measurement of skin water layer characteristics, specific structure of temperature field in IR band of spectrum under laboratory and large-scale conditions, variations of humidity content at different state of skin water layer in the process of interaction between two media. Measurements of the radiation fog of different scales are taken, which possibly forms the false and real horizons being one of the interferences for transmission of IR radiation to recording channels. Parameters and specific manifestation of this interference are measured. Conclusion. Based on the analysis and experiments it is confirmed that there are abnormal localizations of humidity content of different scales, which produce radiation temperature variations.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46496282","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 : 2023-06-06DOI: 10.24937/2542-2324-2023-2-404-135-139
I. Grushetsky, I.O. Malinin
Object and purpose of research. This paper discusses induced noise radiation into water from spherical uniform bodies and spherical shells to estimate the acceptability of commonly used simplified approach to prediction of low-frequency acoustic signatures for marine objects. Materials and methods.The calculations were performed as per analytical expressions and numerical simulation techniques (FEM). Main results. The study has shown that increasing the density of radiating body and increasing mechanical resistance of shell at the location of exciting force reduces noise radiation. Resonant noise radiation typically occurs due to structural non-uniformities of marine objects, like local masses needed to ensure zero buoyancy, e.g. equipment or ballast. These nonuniformities create reactive forces that reach their peak values at resonant frequencies of the hull. Conclusion. The study concludes that reliable computational estimate of low-frequency acoustic signatures must take into account both mechanical resistance and non-uniform distribution of masses along hull, which can be done in numerical simulation packages.
{"title":"Low-frequency sound radiation of marine object","authors":"I. Grushetsky, I.O. Malinin","doi":"10.24937/2542-2324-2023-2-404-135-139","DOIUrl":"https://doi.org/10.24937/2542-2324-2023-2-404-135-139","url":null,"abstract":"Object and purpose of research. This paper discusses induced noise radiation into water from spherical uniform bodies and spherical shells to estimate the acceptability of commonly used simplified approach to prediction of low-frequency acoustic signatures for marine objects. Materials and methods.The calculations were performed as per analytical expressions and numerical simulation techniques (FEM). Main results. The study has shown that increasing the density of radiating body and increasing mechanical resistance of shell at the location of exciting force reduces noise radiation. Resonant noise radiation typically occurs due to structural non-uniformities of marine objects, like local masses needed to ensure zero buoyancy, e.g. equipment or ballast. These nonuniformities create reactive forces that reach their peak values at resonant frequencies of the hull. Conclusion. The study concludes that reliable computational estimate of low-frequency acoustic signatures must take into account both mechanical resistance and non-uniform distribution of masses along hull, which can be done in numerical simulation packages.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45095736","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 : 2023-02-15DOI: 10.24937/2542-2324-2023-1-403-15-30
A. Sokolov, S.A. Аleksandrov, G. Kanevsky
Object and purpose of research. This paper discusses pump jet propulsor. The purpose of the study was to improve its elements through experimental and theoretical investigation of its hydrodynamics and cavitation properties. This work is a part of the project intended to develop an application for a useful model. Subject matter and methods. To achieve its purposes, the work follows both theoretical and experimental research methods of ship theory. Numerical simulation of pump jet operation was performed in Siemens StarCCM+ commercial software package, and also as per in-house Krylov State Research Centre calculation methods for unviscous and viscous flows. Main results. The study suggests rotor and stator blade profiles that improve hydrodynamic and cavitation performance of basic pump jet versions. It also suggests updated shapes for pump jet stator and aft fairing. The study has shown that these improvements will increase the efficiency of pump jets by 3–5% as compared to the basic version, and will also eliminate several types of cavitation. Conclusion. The study was meant to improve pump jet elements so as to eliminate the flaws of the basic pump jet version. The results will be helpful in further pump jet design and development of the application for useful model.
{"title":"Improving geometry of marine pump jet","authors":"A. Sokolov, S.A. Аleksandrov, G. Kanevsky","doi":"10.24937/2542-2324-2023-1-403-15-30","DOIUrl":"https://doi.org/10.24937/2542-2324-2023-1-403-15-30","url":null,"abstract":"Object and purpose of research. This paper discusses pump jet propulsor. The purpose of the study was to improve its elements through experimental and theoretical investigation of its hydrodynamics and cavitation properties. This work is a part of the project intended to develop an application for a useful model. Subject matter and methods. To achieve its purposes, the work follows both theoretical and experimental research methods of ship theory. Numerical simulation of pump jet operation was performed in Siemens StarCCM+ commercial software package, and also as per in-house Krylov State Research Centre calculation methods for unviscous and viscous flows. Main results. The study suggests rotor and stator blade profiles that improve hydrodynamic and cavitation performance of basic pump jet versions. It also suggests updated shapes for pump jet stator and aft fairing. The study has shown that these improvements will increase the efficiency of pump jets by 3–5% as compared to the basic version, and will also eliminate several types of cavitation. Conclusion. The study was meant to improve pump jet elements so as to eliminate the flaws of the basic pump jet version. The results will be helpful in further pump jet design and development of the application for useful model.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45263295","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 : 2023-02-15DOI: 10.24937/2542-2324-2023-1-403-149-158
B. Gorodetsky, А. Vishnevsky, A. Gorshkov
Object and purpose of research. This paper discusses organization of the measures intended to enhance EMC and electromagnetic robustness of ships in accordance with regulations. The purpose is to obtain an optimal procedure for practical implementation of KSRC-developed methodology intended to ensure electromagnetic compatibility of equipment aboard marine objects and their robustness against electromagnetic attacks. Subject matter and methods. The methodology mentioned above is centered around scientific and engineering support of the object at all stages of its life cycle. It requires participation of numerous organizations and enterprises in charge of specifications development, equipment design, testing (acceptance, etc.), as well as operation of the object. Therefore, development of an optimal scenario for participation of all these organizations and enterprises at various life cycle stages of marine object becomes a relevant task. Main results. This paper discusses the whole participation scenario for all organizations and enterprises over the entire life cycle of marine objects, including the most sophisticated ones, i.e. ships, in terms of practical implementation for KSRCdeveloped methodology of EMC and electromagnetic robustness enhancement. It demonstrates that this task requires special test facilities, with enumeration of their respective key capabilities. It also describes the peculiarities of industrial degaussing/deperming/EMC test center established at KSRC in accordance with the requirements set out in this paper. Conclusion. Practical implementation of EMC and electromagnetic robustness enhancement methodology for marine objects is centered around optimal combinations of protective tools and measures (taken by both equipment manufacturers and ship designers coordinated by a dedicated agency in charge of scientific and engineering support) and requires optimal work organization, as well as optimal interaction between all stakeholders over the entire life cycle of marine object. Practical implementation scenario for this methodology relies on industrial test facilities and makes it possible to achieve EMC and electromagnetic robustness of various objects, including ships, in an optimal manner.
{"title":"Organization of EMC enhancement measures for modern ships","authors":"B. Gorodetsky, А. Vishnevsky, A. Gorshkov","doi":"10.24937/2542-2324-2023-1-403-149-158","DOIUrl":"https://doi.org/10.24937/2542-2324-2023-1-403-149-158","url":null,"abstract":"Object and purpose of research. This paper discusses organization of the measures intended to enhance EMC and electromagnetic robustness of ships in accordance with regulations. The purpose is to obtain an optimal procedure for practical implementation of KSRC-developed methodology intended to ensure electromagnetic compatibility of equipment aboard marine objects and their robustness against electromagnetic attacks. Subject matter and methods. The methodology mentioned above is centered around scientific and engineering support of the object at all stages of its life cycle. It requires participation of numerous organizations and enterprises in charge of specifications development, equipment design, testing (acceptance, etc.), as well as operation of the object. Therefore, development of an optimal scenario for participation of all these organizations and enterprises at various life cycle stages of marine object becomes a relevant task. Main results. This paper discusses the whole participation scenario for all organizations and enterprises over the entire life cycle of marine objects, including the most sophisticated ones, i.e. ships, in terms of practical implementation for KSRCdeveloped methodology of EMC and electromagnetic robustness enhancement. It demonstrates that this task requires special test facilities, with enumeration of their respective key capabilities. It also describes the peculiarities of industrial degaussing/deperming/EMC test center established at KSRC in accordance with the requirements set out in this paper. Conclusion. Practical implementation of EMC and electromagnetic robustness enhancement methodology for marine objects is centered around optimal combinations of protective tools and measures (taken by both equipment manufacturers and ship designers coordinated by a dedicated agency in charge of scientific and engineering support) and requires optimal work organization, as well as optimal interaction between all stakeholders over the entire life cycle of marine object. Practical implementation scenario for this methodology relies on industrial test facilities and makes it possible to achieve EMC and electromagnetic robustness of various objects, including ships, in an optimal manner.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42366704","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 : 2023-02-15DOI: 10.24937/2542-2324-2023-1-403-67-77
Y. Shved
Object and purpose of research. The solution discussed in this paper is applicable to the propellers (including those with oscillating blades) operating in fluids, and is intended to ensure self-adjustment of blades to the optimal attack angle. Subject matter and methods. Blade self-adjustment to the optimal attack angle was achieved through one of the properties of the boundary layer for viscous flow around the foil system: this layer acquires different thickness at the opposite sides of foils with non-zero installation angle, thus becoming an asymmetric displacement body. The propeller intended to use this property had its blade and a stabilizing foil attached to a common axe so that the rotation axis of both the blade and the foil was between the application points of the hydrodynamic resultant force (i.e. centers of pressure) for the blade with and without the stabilizing foil. The locations of pressure centers were calculated as per the linear theory. This property of the propulsion system was confirmed experimentally. Main results. It was experimentally demonstrated that proper selection of the rotation axis coordinate in a viscous fluid creates a zone of stable attack angles. This zone also exists for symmetric foils arranged one after another with non-zero installation angle. It means that these foils could be used in a fin-type propulsor, but this will require a control device preventing blade lock due to reversal of oscillation direction. In the suggested solution, blade axis is connected with driving rods by means of steering arms, and the driving rods themselves have guides locking blade tips when oscillation direction changes. Conclusion. The solution suggested in this paper has been experimentally validated, and it paves way to introduction of simple but efficient fin-type propulsors. Following this design, the author suggests a flipper with increased propulsion efficiency in a wide range of speeds, as well as a propulsor based on hinged hydrofoils: this design does not need propeller to maintain the speed.
{"title":"Self-stabilizing propeller","authors":"Y. Shved","doi":"10.24937/2542-2324-2023-1-403-67-77","DOIUrl":"https://doi.org/10.24937/2542-2324-2023-1-403-67-77","url":null,"abstract":"Object and purpose of research. The solution discussed in this paper is applicable to the propellers (including those with oscillating blades) operating in fluids, and is intended to ensure self-adjustment of blades to the optimal attack angle. Subject matter and methods. Blade self-adjustment to the optimal attack angle was achieved through one of the properties of the boundary layer for viscous flow around the foil system: this layer acquires different thickness at the opposite sides of foils with non-zero installation angle, thus becoming an asymmetric displacement body. The propeller intended to use this property had its blade and a stabilizing foil attached to a common axe so that the rotation axis of both the blade and the foil was between the application points of the hydrodynamic resultant force (i.e. centers of pressure) for the blade with and without the stabilizing foil. The locations of pressure centers were calculated as per the linear theory. This property of the propulsion system was confirmed experimentally. Main results. It was experimentally demonstrated that proper selection of the rotation axis coordinate in a viscous fluid creates a zone of stable attack angles. This zone also exists for symmetric foils arranged one after another with non-zero installation angle. It means that these foils could be used in a fin-type propulsor, but this will require a control device preventing blade lock due to reversal of oscillation direction. In the suggested solution, blade axis is connected with driving rods by means of steering arms, and the driving rods themselves have guides locking blade tips when oscillation direction changes. Conclusion. The solution suggested in this paper has been experimentally validated, and it paves way to introduction of simple but efficient fin-type propulsors. Following this design, the author suggests a flipper with increased propulsion efficiency in a wide range of speeds, as well as a propulsor based on hinged hydrofoils: this design does not need propeller to maintain the speed.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45835790","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 : 2023-02-15DOI: 10.24937/2542-2324-2023-1-403-167-182
V. Magarovsky, V. Polovinkin, A. Pustoshny, O. Savchenko
Object and purpose of research. This work was intended to analyse technical solutions that could contribute to power efficiency of in-service fleet in the light of new IMO policy aimed at the mitigation of greenhouse gas emissions from international marine traffic. This is the second publication in the series of articles discussing various aspects of this new IMO policy, as well as shipbuilding challenges that have to be faced in order to meet relevant requirements. Subject matter and methods. This work is an analytical review of available publications on above-mentioned topic. It relies on Krylov State Research Centre experience in the optimization of ship fuel consumption, as well as on the results of IMO correspondence group discussions on power efficiency with participation of Krylov State Research Centre and RS experts. Main results. This paper discusses the efficiency of measures taken all over the world to improve fuel efficiency of ships taking into account the experience of their implementation at the early stage of IMO regulations for greenhouse gas emissions. It is shown that each of these measures might reduce the emissions from global marine traffic by ~5%, which is not enough to achieve the final goal, i.e. 70% reduction in emissions by the year 2050 as compared to 2008. Besides, these measures cannot be implemented in full due to certain limitations. For example, in Russia the main obstacle is that practically all its ships must have an ice class, so they cannot use a whole number of various power-saving devices because of their vulnerability to ice impact. Still, provided that power-saving devices are robust enough, they might prove to be a useful (and sometimes the only possible) way to reduce gas emissions of a ship after several years of service. It is incorporated to the system rating the ships in terms of their emission score assigned as per the new provisions of MARPOL Annex VI adopted in 2021, see Part I of this series. Conclusion. Analysis of power saving measures (along with assessment of their efficiency and applicability to ice-class ships) enables a justified selection of power efficiency enhancement tools for a ship in case its annual Carbon Intensity Indicator (CII) goes beyond IMO thresholds that gradually become more and more stringent in accordance with new provisions of MARPOL Annex VI. Still, these measures will not be sufficient to achieve target levels of emission reduction prescribed by IMO. These levels could only be achieved through radical changes in marine power systems, like the transition to alternative fuels with low or zero carbon footprint. This matter will be discussed in the third article of this series.
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