It is shown that modern achievements in the field of experimental and theoretical researches and developments of innovative measuring systems for monitoring of non-linear dynamic and kinematic characteristics allow to...It is shown that modern achievements in the field of experimental and theoretical researches and developments of innovative measuring systems for monitoring of non-linear dynamic and kinematic characteristics allow to formulate basics of new academic discipline,designated as“geomechanical thermodynamics”.The following circumstances can be considered as the most important prerequisites for development of this new discipline.(1)Practical completeness of the classical thermodynamics,based on kinetic gas theory and molecular movements in solid bodies;(2)Creation of“formular construction tool”for the description of dynamic and kinematic characteristics of pendulum waves and energy conditions of their occurrence and propagation from dynamic sources,located in multi-phased stressed rock mass and geomaterials with block-hierarchical structure;(3)Principal opportunity to establish formal relations between substantial energy carriers of“packages”of nonlinear pendulum waves(geoblocks of certain hierarchical levels according to their diameters)and“molecules”:their movement,velocity and acceleration of the“molecules”↔“geoblock”;“force interactions between molecules”↔“non-linear elastic interaction between geoblocks”,etc.The term of“geomechanical temperature”is introduced and its analytical expression,which is proportional to kinetic energy of movement of geoblocks with defined volume for their hierarchical subsequence at“confined”conditions of the stressed rock mass,is shown.The similar aspects are discussed,when emission acousticelectromagnetic fields are fixed using corresponding coefficients of mechanical-electrical and mechanicalacoustic transformations.In order to quantitively describe the evolution of energy state of local zones of stressstrain concentration and surroundings of their non-linear influence from catastrophic events at the natural and mine-engineering systems(earthquakes,rock bursts,etc.),the terms of their geomechanical and thermodynamic stages are introduced and specified:Tiei 20;t;;;*T‒with background states ei 20;*T and three major stages ei2t;;T outlined,where(t)is the concentration,(,‒)are the failure and relaxation and(*)is the quasirecovering up to“background”level after the occurred catastrophic event.Using certain examples,the existence of critical elastic energy content of local zones with“meta-stable state”,which is transforming to quasiresonance process of failure and relaxation of“excessive”energy,is shown eTT.展开更多
Experimental studies were conducted on a trapezoidal pendulum wave energy converter in regular waves. To obtain the incident wave height, the analytical method （AM） was used to separate the incident and reflected wa...Experimental studies were conducted on a trapezoidal pendulum wave energy converter in regular waves. To obtain the incident wave height, the analytical method （AM） was used to separate the incident and reflected waves propagating in a wave flume by analysing wave records measured at two locations. The response amplitude operator （RAO）, primary conversion efficiency and the total conversion efficiency of the wave energy converter were studied; furthermore, the power take-off damping coefficients corresponding to the load resistances in the experiment were also obtained. The findings demonstrate that the natural period for a pendulum wave energy converter is relatively large. A lower load resistance gives rise to a larger damping coefficient. The model shows relatively higher wave energy conversion efficiency in the range of 1.0-1.2 s for the incident wave period. The maximum primary conversion efficiency achieved was 55.5%, and the maximum overall conversion efficiency was 39.4%.展开更多
Based on two- and three-dimensional potential flow theories, the width effects on the hydrodynamics of a bottom-hinged trapezoidal pendulum wave energy converter are discussed. The two-dimensional eigenfunction expans...Based on two- and three-dimensional potential flow theories, the width effects on the hydrodynamics of a bottom-hinged trapezoidal pendulum wave energy converter are discussed. The two-dimensional eigenfunction expansion method is used to obtain the diffraction and radiation solutions when the converter width tends to be infinity. The trapezoidal section of the converter is approximated by a rectangular section for simplification. The nonlinear viscous damping effects are accounted for by including a drag term in the two- and three-dimensional methods. It is found that the three- dimensional results are in good agreement with the two-dimensional results when the converter width becomes larger, especially when the converter width is infinity, which shows that both of the methods are reasonable. Meantime, it is also found that the peak value of the conversion efficiency decreases as the converter width increases in short wave periods while increases when the converter width increases in long wave periods.展开更多
A floating type pendulum wave energy converter(FPWEC) with a rotary vane pump as the power take-off system was proposed by Watabe et al.in 1998.They showed that this device had high energy conversion efficiency.In the...A floating type pendulum wave energy converter(FPWEC) with a rotary vane pump as the power take-off system was proposed by Watabe et al.in 1998.They showed that this device had high energy conversion efficiency.In the previous research,the authors conducted 2D wave tank tests in regular waves to evaluate the generating efficiency of FPWEC with a power take-off system composed of pulleys,belts and a generator.As a result,the influence of the electrical load on the generating efficiency was shown.Continuously,the load characteristics of FPWEC are pursued experimentally by using the servo motors to change the damping coefficient in this paper.In a later part of this paper,the motions of the model with the servo motors are compared with that of the case with the same power take-off system as the previous research.From the above experiment,it may be concluded that the maximum primary conversion efficiency is achieved as high as 98%at the optimal load.展开更多
The article focuses on a theoretical and experimental framework for the quantification of interaction between nonlinear geomechnical and physicochemical processes in high-stress coal-bearing rock mass during mining un...The article focuses on a theoretical and experimental framework for the quantification of interaction between nonlinear geomechnical and physicochemical processes in high-stress coal-bearing rock mass during mining under high seismic risk due to large-scale blasting and earthquakes,as well as because of structural and temperature effects.The tests were aimed to examine and study comprehensively the piston mechanism of gas exchange and mass transfer processes,revealed recently at the Institute of Mining,SB RAS,as well as to explain the fact that the earthquake-induced low-velocity(quasi-meter range)pendulum waves(velocity to 1 m/s and frequency of 0.5–5 Hz)could stimulate an increase in the gas content in coal mines.In order to perform laboratory investigation at the Institute of Mining SB RAS,special-purpose stand for analyzing gas exchange and mass transfer processes in coal-bearing geomaterials under various thermodynamic conditions(P,V,T)and gas composition was constructed in cooperation with the Institute of Semiconductors Physics SB RAS.Matching of air flow rate with compression pressures allowed to obtain relations showing that air flow rate increases at the uncertain time interval under the increasing of the compression pressure.The same measurements was carried out with another gases such as Hydrogen H_(2),Helium He,methane CH_(4),carbon dioxide CO_(2) and carbon oxide CO.The laboratory tests aimed to detailed investigation of the previously revealed“piston mechanism”of gas exchange and mass transfer processes in the coal specimens and their quantitative description in terms of theory of the pendulum waves were carried in the first time.Consequently,there are some arguments for the testing of the opportunity of quantitative description of the“piston mechanism”related to gas exchange and mass transfer processes in the scale of coal mines.It is relevant when pendulum waves induced by powerful earthquakes and technical blasting reaches the mine.展开更多
基金support of Russian Foundation for Basic Research(project No.20-05-00051).
文摘It is shown that modern achievements in the field of experimental and theoretical researches and developments of innovative measuring systems for monitoring of non-linear dynamic and kinematic characteristics allow to formulate basics of new academic discipline,designated as“geomechanical thermodynamics”.The following circumstances can be considered as the most important prerequisites for development of this new discipline.(1)Practical completeness of the classical thermodynamics,based on kinetic gas theory and molecular movements in solid bodies;(2)Creation of“formular construction tool”for the description of dynamic and kinematic characteristics of pendulum waves and energy conditions of their occurrence and propagation from dynamic sources,located in multi-phased stressed rock mass and geomaterials with block-hierarchical structure;(3)Principal opportunity to establish formal relations between substantial energy carriers of“packages”of nonlinear pendulum waves(geoblocks of certain hierarchical levels according to their diameters)and“molecules”:their movement,velocity and acceleration of the“molecules”↔“geoblock”;“force interactions between molecules”↔“non-linear elastic interaction between geoblocks”,etc.The term of“geomechanical temperature”is introduced and its analytical expression,which is proportional to kinetic energy of movement of geoblocks with defined volume for their hierarchical subsequence at“confined”conditions of the stressed rock mass,is shown.The similar aspects are discussed,when emission acousticelectromagnetic fields are fixed using corresponding coefficients of mechanical-electrical and mechanicalacoustic transformations.In order to quantitively describe the evolution of energy state of local zones of stressstrain concentration and surroundings of their non-linear influence from catastrophic events at the natural and mine-engineering systems(earthquakes,rock bursts,etc.),the terms of their geomechanical and thermodynamic stages are introduced and specified:Tiei 20;t;;;*T‒with background states ei 20;*T and three major stages ei2t;;T outlined,where(t)is the concentration,(,‒)are the failure and relaxation and(*)is the quasirecovering up to“background”level after the occurred catastrophic event.Using certain examples,the existence of critical elastic energy content of local zones with“meta-stable state”,which is transforming to quasiresonance process of failure and relaxation of“excessive”energy,is shown eTT.
基金financially supported by the Special Fund for Marine Renewable Energy of the Ministry of Finance of China(Grant No.GD2010ZC02)
文摘Experimental studies were conducted on a trapezoidal pendulum wave energy converter in regular waves. To obtain the incident wave height, the analytical method （AM） was used to separate the incident and reflected waves propagating in a wave flume by analysing wave records measured at two locations. The response amplitude operator （RAO）, primary conversion efficiency and the total conversion efficiency of the wave energy converter were studied; furthermore, the power take-off damping coefficients corresponding to the load resistances in the experiment were also obtained. The findings demonstrate that the natural period for a pendulum wave energy converter is relatively large. A lower load resistance gives rise to a larger damping coefficient. The model shows relatively higher wave energy conversion efficiency in the range of 1.0-1.2 s for the incident wave period. The maximum primary conversion efficiency achieved was 55.5%, and the maximum overall conversion efficiency was 39.4%.
基金supported by the Special Fund for Marine Renewable Energy of the Ministry of Finance of China(No.GD2010ZC02)
文摘Based on two- and three-dimensional potential flow theories, the width effects on the hydrodynamics of a bottom-hinged trapezoidal pendulum wave energy converter are discussed. The two-dimensional eigenfunction expansion method is used to obtain the diffraction and radiation solutions when the converter width tends to be infinity. The trapezoidal section of the converter is approximated by a rectangular section for simplification. The nonlinear viscous damping effects are accounted for by including a drag term in the two- and three-dimensional methods. It is found that the three- dimensional results are in good agreement with the two-dimensional results when the converter width becomes larger, especially when the converter width is infinity, which shows that both of the methods are reasonable. Meantime, it is also found that the peak value of the conversion efficiency decreases as the converter width increases in short wave periods while increases when the converter width increases in long wave periods.
文摘A floating type pendulum wave energy converter(FPWEC) with a rotary vane pump as the power take-off system was proposed by Watabe et al.in 1998.They showed that this device had high energy conversion efficiency.In the previous research,the authors conducted 2D wave tank tests in regular waves to evaluate the generating efficiency of FPWEC with a power take-off system composed of pulleys,belts and a generator.As a result,the influence of the electrical load on the generating efficiency was shown.Continuously,the load characteristics of FPWEC are pursued experimentally by using the servo motors to change the damping coefficient in this paper.In a later part of this paper,the motions of the model with the servo motors are compared with that of the case with the same power take-off system as the previous research.From the above experiment,it may be concluded that the maximum primary conversion efficiency is achieved as high as 98%at the optimal load.
基金support of Russian Science Foundation (Project No.23-17-00148)as a part of R&D project (State registry No.121062200075-4).
文摘The article focuses on a theoretical and experimental framework for the quantification of interaction between nonlinear geomechnical and physicochemical processes in high-stress coal-bearing rock mass during mining under high seismic risk due to large-scale blasting and earthquakes,as well as because of structural and temperature effects.The tests were aimed to examine and study comprehensively the piston mechanism of gas exchange and mass transfer processes,revealed recently at the Institute of Mining,SB RAS,as well as to explain the fact that the earthquake-induced low-velocity(quasi-meter range)pendulum waves(velocity to 1 m/s and frequency of 0.5–5 Hz)could stimulate an increase in the gas content in coal mines.In order to perform laboratory investigation at the Institute of Mining SB RAS,special-purpose stand for analyzing gas exchange and mass transfer processes in coal-bearing geomaterials under various thermodynamic conditions(P,V,T)and gas composition was constructed in cooperation with the Institute of Semiconductors Physics SB RAS.Matching of air flow rate with compression pressures allowed to obtain relations showing that air flow rate increases at the uncertain time interval under the increasing of the compression pressure.The same measurements was carried out with another gases such as Hydrogen H_(2),Helium He,methane CH_(4),carbon dioxide CO_(2) and carbon oxide CO.The laboratory tests aimed to detailed investigation of the previously revealed“piston mechanism”of gas exchange and mass transfer processes in the coal specimens and their quantitative description in terms of theory of the pendulum waves were carried in the first time.Consequently,there are some arguments for the testing of the opportunity of quantitative description of the“piston mechanism”related to gas exchange and mass transfer processes in the scale of coal mines.It is relevant when pendulum waves induced by powerful earthquakes and technical blasting reaches the mine.
