Aiming at the safety problem of the stage separation of parallel reusable high-speed air vehicles,this paper studies the unsteady test method and focuses on deriving a similarity law of parallel stage separation free-...Aiming at the safety problem of the stage separation of parallel reusable high-speed air vehicles,this paper studies the unsteady test method and focuses on deriving a similarity law of parallel stage separation free-flight wind tunnel tests.The new similarity law considers the influences of aerodynamic force and gravity on the motions of the two stages,as well as the influence of aerodynamic interference between the two stages on each other’s motion.From the perspective of multiangle physical equations,the conditions to ensure that the two-stage separation trajectory of a wind tunnel test is similar to that of a real air vehicle are derived innovatively,so as to ensure the authenticity and credibility of wind tunnel test results.The similarity law is verified by an HIFiRE-5 air vehicle,and the separation trajectories of wind tunnel tests and the real air vehicle are obtained by numerical simulation.The research shows that the similarity law derived in this paper can ensure that wind tunnel free-flight tests have the ability to predict the two-stage separation characteristics of real parallel vehicles.By analyzing the separation trajectory curve of the typical state,it is found that the new method can ensure that the trajectory error of a wind tunnel test does not exceed 1%,which indicates that this method is credible.The establishment of the new method lays the foundation for subsequent wind tunnel tests and provides support for research on the safety of the stage separation of parallel reusable air vehicles.展开更多
In the process of stage separation of recoverable liquid launch vehicles,because of the large amount of residual fuel in the storage tanks,the influence of liquid sloshing on separation safety must be considered.Consi...In the process of stage separation of recoverable liquid launch vehicles,because of the large amount of residual fuel in the storage tanks,the influence of liquid sloshing on separation safety must be considered.Considering calculation simplicity and operation practicability,the Moving Pulsating Ball Model(MPBM)of large amplitude liquid sloshing is introduced into the calculation of launch vehicle stage separation.Combining the dynamic equation of the model with the energy relationship during"breathing movement",the formula calculating the force of liquid on the rigid body is derived.Compared with the calculations of commercial CFD calculation software,the accuracy of MPBM model is verified.Then,all the external forces and moments are applied to the rigid body of the stages,so that the translational and rotational dynamic equations of the stages are obtained respectively.According to the relative position of the two stages,the geometric shape of the interstage section and the engine of the second stage,the minimum clearance in the separation process can be decided to guarantee that the separation process is safe.展开更多
The fact that water requirements are a major problem for present and future developments in material beneficiation, and the construction of a new power plant in South Africa, forms the basis for the utilization of a R...The fact that water requirements are a major problem for present and future developments in material beneficiation, and the construction of a new power plant in South Africa, forms the basis for the utilization of a Rotary Triboelectrostatic Separator (RTS) for beneficiation of South African pulverized coal. The cleaning potential of Majuba and Koorfontein coal was first evaluated using kinetic froth flotation tests on the -177 μm coal fraction. The RTS tests were conducted under varied process parameters. Parameters such as applied separating voltage, air injection velocity, particle feed rate and splitter position were investigated. Two stage separation results show that the RTS reduced Majuba coal initially containing about 30% ash to a clean product of 14.30%, or 19.46%, ash at a combustible recovery of 15.10%, or 53.02%, respectively. Similar separation performance was also achieved with the Koorfontein coal. The mineral and organic compositions in the feed, after single stage and after the second stage separations were characterized using X-ray diffraction analysis. The results show a better separation for the second stage coal products.展开更多
The article analyzes the main options for design solutions of separation devices of promising launch vehicles and payloads without using pyrotechnic elements,such as the“Clamp Band”type,“ball”and“petal”types,as ...The article analyzes the main options for design solutions of separation devices of promising launch vehicles and payloads without using pyrotechnic elements,such as the“Clamp Band”type,“ball”and“petal”types,as well as the bandage-based separation device.Parametric redundancy has been performed to achieve the required level of the reliability,providing the necessary coefficient of parametricmargin.Engineering Critical Assessment of structural elements of the proposed separation devices by using the scorecardmethod is analyzed and considered.The reliability requirements are considered,whichmust be confirmed during complex experimental processing,including laboratory debugging,control developing,control sampling,control finishing and manufacturing tests of individual large-sized elements and subsystems included in the proposed separation devices,as well as recommendations for ensuring the reliability of their operation at the design development stage.展开更多
The paper develops and investigates various options for separating the first and second stages of a promising launch vehicle without using pyrotechnic elements(such as the“Clamp Band”type,“petal”and“ball”types)....The paper develops and investigates various options for separating the first and second stages of a promising launch vehicle without using pyrotechnic elements(such as the“Clamp Band”type,“petal”and“ball”types).A review and analysis of the applicability of pyrotechnic elements as part of separation devices of existing and promising launch vehicles was carried out,as a result,it was revealed that their use is difficult for technological reasons related to the need for specialized devices and equipment for accurate control of the detonation process and the likelihood of a large number of fragments and shock loads during operation,which negatively affects the provision of specified structural and operational characteristics of launch vehicles.The basic requirements for ensuring the rational operation of the proposed separation devices,taking into account the possibility of their multiple use,are considered.Experimental and mathematical modeling of relative motion of the stages separating according to the“cold”scheme under the influence of static and dynamic loads has been carried out,and rational technical solutions and design and technological approaches for the proposed separation devices have been selected.The results of the research on assessment of the stress-strain state of structural elements of the proposed separation devices without using pyrotechnic elements in various configurations,as well as their novelty,are presented.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U21B2054 and 11772317).
文摘Aiming at the safety problem of the stage separation of parallel reusable high-speed air vehicles,this paper studies the unsteady test method and focuses on deriving a similarity law of parallel stage separation free-flight wind tunnel tests.The new similarity law considers the influences of aerodynamic force and gravity on the motions of the two stages,as well as the influence of aerodynamic interference between the two stages on each other’s motion.From the perspective of multiangle physical equations,the conditions to ensure that the two-stage separation trajectory of a wind tunnel test is similar to that of a real air vehicle are derived innovatively,so as to ensure the authenticity and credibility of wind tunnel test results.The similarity law is verified by an HIFiRE-5 air vehicle,and the separation trajectories of wind tunnel tests and the real air vehicle are obtained by numerical simulation.The research shows that the similarity law derived in this paper can ensure that wind tunnel free-flight tests have the ability to predict the two-stage separation characteristics of real parallel vehicles.By analyzing the separation trajectory curve of the typical state,it is found that the new method can ensure that the trajectory error of a wind tunnel test does not exceed 1%,which indicates that this method is credible.The establishment of the new method lays the foundation for subsequent wind tunnel tests and provides support for research on the safety of the stage separation of parallel reusable air vehicles.
基金supported by the National Natural Science Foundation of China(Nos.12132002,12202044)。
文摘In the process of stage separation of recoverable liquid launch vehicles,because of the large amount of residual fuel in the storage tanks,the influence of liquid sloshing on separation safety must be considered.Considering calculation simplicity and operation practicability,the Moving Pulsating Ball Model(MPBM)of large amplitude liquid sloshing is introduced into the calculation of launch vehicle stage separation.Combining the dynamic equation of the model with the energy relationship during"breathing movement",the formula calculating the force of liquid on the rigid body is derived.Compared with the calculations of commercial CFD calculation software,the accuracy of MPBM model is verified.Then,all the external forces and moments are applied to the rigid body of the stages,so that the translational and rotational dynamic equations of the stages are obtained respectively.According to the relative position of the two stages,the geometric shape of the interstage section and the engine of the second stage,the minimum clearance in the separation process can be decided to guarantee that the separation process is safe.
基金the financial support of the South African National Energy Research Institute (SANERI)
文摘The fact that water requirements are a major problem for present and future developments in material beneficiation, and the construction of a new power plant in South Africa, forms the basis for the utilization of a Rotary Triboelectrostatic Separator (RTS) for beneficiation of South African pulverized coal. The cleaning potential of Majuba and Koorfontein coal was first evaluated using kinetic froth flotation tests on the -177 μm coal fraction. The RTS tests were conducted under varied process parameters. Parameters such as applied separating voltage, air injection velocity, particle feed rate and splitter position were investigated. Two stage separation results show that the RTS reduced Majuba coal initially containing about 30% ash to a clean product of 14.30%, or 19.46%, ash at a combustible recovery of 15.10%, or 53.02%, respectively. Similar separation performance was also achieved with the Koorfontein coal. The mineral and organic compositions in the feed, after single stage and after the second stage separations were characterized using X-ray diffraction analysis. The results show a better separation for the second stage coal products.
基金Financial support was provided by the Ministry of Science and Higher Education of the Russian Federation(project FSFF-2023-0007).
文摘The article analyzes the main options for design solutions of separation devices of promising launch vehicles and payloads without using pyrotechnic elements,such as the“Clamp Band”type,“ball”and“petal”types,as well as the bandage-based separation device.Parametric redundancy has been performed to achieve the required level of the reliability,providing the necessary coefficient of parametricmargin.Engineering Critical Assessment of structural elements of the proposed separation devices by using the scorecardmethod is analyzed and considered.The reliability requirements are considered,whichmust be confirmed during complex experimental processing,including laboratory debugging,control developing,control sampling,control finishing and manufacturing tests of individual large-sized elements and subsystems included in the proposed separation devices,as well as recommendations for ensuring the reliability of their operation at the design development stage.
基金Financial support was provided by the Ministry of Science and Higher Education of the Russian Federation(project FSFF-2023-0007).
文摘The paper develops and investigates various options for separating the first and second stages of a promising launch vehicle without using pyrotechnic elements(such as the“Clamp Band”type,“petal”and“ball”types).A review and analysis of the applicability of pyrotechnic elements as part of separation devices of existing and promising launch vehicles was carried out,as a result,it was revealed that their use is difficult for technological reasons related to the need for specialized devices and equipment for accurate control of the detonation process and the likelihood of a large number of fragments and shock loads during operation,which negatively affects the provision of specified structural and operational characteristics of launch vehicles.The basic requirements for ensuring the rational operation of the proposed separation devices,taking into account the possibility of their multiple use,are considered.Experimental and mathematical modeling of relative motion of the stages separating according to the“cold”scheme under the influence of static and dynamic loads has been carried out,and rational technical solutions and design and technological approaches for the proposed separation devices have been selected.The results of the research on assessment of the stress-strain state of structural elements of the proposed separation devices without using pyrotechnic elements in various configurations,as well as their novelty,are presented.
