The Analysis Of Hydrodynamic Characteristics For New Type Of Deep-sea Drilling Device

Oil as the world's main source of energy supplies, promoting the country's economic development has become an important strategic resource. In recent years, with the exploitation's scale of offshore oil and gas continuously enlarge, the resources in the shallow sea has nearly been exhausted, so the countries in the world have shifted their attention to deep waters. At the same time, oil reserves are abundant in South China Sea and that has been the hope of our country's offshore oil exploitation. Sub Surface BOP is the latest development of deep water drilling device in the field of International Marine Engineering. The related technology and design about the new drilling device (Artificial Buoyant Seabed, abbreviated to ABS) is still in the stage of exploring and reforming. For our country, it is not only the chance to catch up with the countries with developed marine technology, but also the challenge to our scientific research and technology.The first part of the thesis mainly introduces the fundamental theory and method of the research about hydrodynamic performance. At first, the matter of flow field characteristics and fluid-structure interaction of flow around bluff body are stated, including locking phenomenon and different vortex shedding modes. And then, the theory of motion of platform in waves and turbulence theory are introduced, including linear wave theory, frequency-domain analysis method, turbulence models, and so on. At last, the dynamic mesh model and UDF are described, applied to mesh regeneration and self-defining function for the numerical simulation of moving object.The hydrodynamic performance of ABS and ABS system induced by drilling platform's movement are studied respectively in the second part of the thesis. While analyzing the hydrodynamic performance of ABS,the process of flow around ABS and flow induced motion of two-dimensional and three-dimensional model are simulated. Moreover, the forces and vortex shedding patterns from different velocities and flow directions are compared, and the spectral analysis of lift force under the condition of flow induced motion are carried out. While analyzing the hydrodynamic performance of ABS system, firstly, Sesam software is applied to calculate the motion of mooring drilling platform under the action of different frequency regular waves. And then, the hydrodynamic analysis and key-node strength analysis of ABS system are carried out, considering the motion of ABS system induced by platform's motion.The third part of the thesis mainly introduces the experimental study about united physical model of drilling platform and ABS system. Beginning from related development history of the hydrodynamic model test, the significance of model experiment and the general situation of ocean engineering basin at home and abroad are stated. And then, how to select the scale ratio is introduced briefly, as well as the hybrid model testing technology in deep-sea model experiment, the simulation of ocean environmental conditions, measuring instruments, acquisition system, and so on. And the experimental operating conditions are design according to ocean environmental conditions. At last, the method of numerical prediction is perfected through analyzing the experimental results, including the transfer function of drilling platform's motion in waves and the forces acting on ABS system, and comparing with the numerical results.