海洋温差能发电装置中冷水管动力性能分析
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摘要
不考虑波浪、海流以及平台运动的作用,研究管内流动对冷水管动力性能的影响。基于悬臂输液管道梁模型,通过轴向流速比α、流速角比ψ和切向流速比φ三个进流口流场参数描述自由端边界条件,获得冷水管在内流作用下的控制方程。从流体动力项对管道做功的角度分析发现,φ对管道失稳的临界流速有很大的影响,并且φ=0被认为是对进流口流场的正确描述;然而,通过Galerkin法分析发现,φ=0的进流口流场模型不能解释进流口压降Δp对动态失稳基本没有影响的试验现象。相反,φ≠0的进流口流场模型在使得进流口压降Δp的影响几乎为零的同时,还能够获得较大的临界流速,与Kuiper观察的试验现象相符。切向流速比φ的正确评估是准确预测临界流速的前提条件。
Regardless of the role of waves,currents,and platform motions,the effect of the internal flow on the dynamics of the cold water pipe is studied. Based on the cantilevered conveying fluid pipe's beam model,the boundary condition at the free end is described by the axial flow velocity ratio α,the flow angle ratio ψ and the tangential flow velocity ratio φ,and the governing equation of the cold water pipe under the action of internal flow is obtained. From the perspective of the work done on the pipe by the fluid-dynamics forces,it is found that φ has a great influence on the critical flow velocity of the pipe instability,and φ = 0 is considered as the correct description of the inlet flow field. However,by the Galerkin method,the inlet flow-field model with φ = 0 cannot explain the experimental phenomenon that the inlet depressurisation Δp has almost no effect on the flutter. On the contrary,the inlet flow field model of φ ≠ 0 makes the influence of the depressurisation Δp almost zero,and also obtains a larger critical flow velocity,which is consistent with the experimental phenomenon observed by Kuiper. The correct assessment of φ is a prerequisite for accurately predicting the critical flow velocity.
Regardless of the role of waves,currents,and platform motions,the effect of the internal flow on the dynamics of the cold water pipe is studied. Based on the cantilevered conveying fluid pipe's beam model,the boundary condition at the free end is described by the axial flow velocity ratio α,the flow angle ratio ψ and the tangential flow velocity ratio φ,and the governing equation of the cold water pipe under the action of internal flow is obtained. From the perspective of the work done on the pipe by the fluid-dynamics forces,it is found that φ has a great influence on the critical flow velocity of the pipe instability,and φ = 0 is considered as the correct description of the inlet flow field. However,by the Galerkin method,the inlet flow-field model with φ = 0 cannot explain the experimental phenomenon that the inlet depressurisation Δp has almost no effect on the flutter. On the contrary,the inlet flow field model of φ ≠ 0 makes the influence of the depressurisation Δp almost zero,and also obtains a larger critical flow velocity,which is consistent with the experimental phenomenon observed by Kuiper. The correct assessment of φ is a prerequisite for accurately predicting the critical flow velocity.
引文
[1]苏佳纯,曾恒一,肖钢,等.海洋温差能发电技术研究现状及在我国的发展前景[J].中国海上油气,2012,24(4):84-98.(SU Jiachun,ZENG Hengyi,XIAO Gang,et al. Research status of ocean thermal energy conversion and its development prospect in China[J]. China Offshore Oil and Gas,2012,24(4):84-98.(in Chinese))
[2]薛桂芳,武文,刘洪滨,等.浅谈海洋温差能及其可持续利用[J].中国海洋大学学报,2008(2):15-19.(XUE Guifang,WU Wen,LIU Hongbin,et al. Discussion on ocean thermal energy conversion and its sustainable utilization[J]. Journal of Ocean University of China,2008(2):15-19.(in Chinese))
[3] Makai ocean engineering. ocean thermal energy conversion[EB/OL]. https:∥www. makai. com/ocean-thermal-energyconversion/.
[4]李伟,赵镇南,王迅,等.海洋温差能发电技术的现状与前景[J].海洋工程,2004,22(2):105-108.(LI Wei,ZHAO Zhennan,WANG Xun,et al. Current status and prospect of ocean thermal energy conversion[J]. The Ocean Engineering,2004,22(2):105-108.(in Chinese))
[5] HALKYARD J,SHEIKH R,MARINHO T,et al. Current developments in the validation of numerical methods for predicting the responses of an ocean thermal energy conversion(OTEC)system cold water pipe[C]∥Proceedings of the 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014:V007T12A028-V007T12A028.
[6] PAIDOUSSIS M P. Fluid-structure interactions:slender structures and axial flow[M]. Academic Press,2014:254-268.
[7] PADOUSSIS M P,LUU T P. Dynamics of a pipe aspirating fluid such as might be used in ocean mining[J]. Journal of Energy Resources Technology,1985,107(2):250-255.
[8] CUI H,TANI J. Effect of boundary conditions on the stability of a cantilever pipe discharging and aspirating fluid[J]. JSME International Journal,Ser. C,Dynamics,Control,Robotics,Design and Manufacturing,1996,39(1):20-24.
[9] PADOUSSIS M P. Aspirating pipes do not flutter at infinitesimally small flow[J]. Journal of Fluids and Structures,1999,13(3):419-425.
[10] KUIPER G L,METRIKINE A V. Dynamic stability of a submerged,free-hanging riser conveying fluid[J]. Journal of Sound and Vibration,2005,280(3):1051-1065.
[11] PADOUSSIS M P,SEMLER C,WADHAM-GAGNON M. A reappraisal of why aspirating pipes do not flutter at infinitesimal flow[J]. Journal of Fluids and Structures,2005,20(1):147-156.
[12] KUIPER G L. Stability of offshore risers conveying fluid[D]. Delft:Delft Technical University,2008.
[13] GIACOBBI D B,RINALDI S,SEMLER C,et al. The dynamics of a cantilevered pipe aspirating fluid studied by experimental,numerical and analytical methods[J]. Journal of Fluids and Structures,2012,30:73-96.
[2]薛桂芳,武文,刘洪滨,等.浅谈海洋温差能及其可持续利用[J].中国海洋大学学报,2008(2):15-19.(XUE Guifang,WU Wen,LIU Hongbin,et al. Discussion on ocean thermal energy conversion and its sustainable utilization[J]. Journal of Ocean University of China,2008(2):15-19.(in Chinese))
[3] Makai ocean engineering. ocean thermal energy conversion[EB/OL]. https:∥www. makai. com/ocean-thermal-energyconversion/.
[4]李伟,赵镇南,王迅,等.海洋温差能发电技术的现状与前景[J].海洋工程,2004,22(2):105-108.(LI Wei,ZHAO Zhennan,WANG Xun,et al. Current status and prospect of ocean thermal energy conversion[J]. The Ocean Engineering,2004,22(2):105-108.(in Chinese))
[5] HALKYARD J,SHEIKH R,MARINHO T,et al. Current developments in the validation of numerical methods for predicting the responses of an ocean thermal energy conversion(OTEC)system cold water pipe[C]∥Proceedings of the 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014:V007T12A028-V007T12A028.
[6] PAIDOUSSIS M P. Fluid-structure interactions:slender structures and axial flow[M]. Academic Press,2014:254-268.
[7] PADOUSSIS M P,LUU T P. Dynamics of a pipe aspirating fluid such as might be used in ocean mining[J]. Journal of Energy Resources Technology,1985,107(2):250-255.
[8] CUI H,TANI J. Effect of boundary conditions on the stability of a cantilever pipe discharging and aspirating fluid[J]. JSME International Journal,Ser. C,Dynamics,Control,Robotics,Design and Manufacturing,1996,39(1):20-24.
[9] PADOUSSIS M P. Aspirating pipes do not flutter at infinitesimally small flow[J]. Journal of Fluids and Structures,1999,13(3):419-425.
[10] KUIPER G L,METRIKINE A V. Dynamic stability of a submerged,free-hanging riser conveying fluid[J]. Journal of Sound and Vibration,2005,280(3):1051-1065.
[11] PADOUSSIS M P,SEMLER C,WADHAM-GAGNON M. A reappraisal of why aspirating pipes do not flutter at infinitesimal flow[J]. Journal of Fluids and Structures,2005,20(1):147-156.
[12] KUIPER G L. Stability of offshore risers conveying fluid[D]. Delft:Delft Technical University,2008.
[13] GIACOBBI D B,RINALDI S,SEMLER C,et al. The dynamics of a cantilevered pipe aspirating fluid studied by experimental,numerical and analytical methods[J]. Journal of Fluids and Structures,2012,30:73-96.