The Research On Hydrodynamic Performance Of Classical Tension Leg Platform

With the development of economy,the demand for energy is growing,the exploration of deep water oil and gas will becomes very important in the future,which needs high technical drill platform.TLP as a kind of excellent motion performance of floating platform,has been widely used in the world.The TLP has both semi-fixed and semi-compliant features,it is connected to the sea floor by a series of pretensioned tendons,The tendons provide the horizontal and vertical stiffness for the surface vessel.So the TLP can have an excellent kind of stability in different sea stage.First of all,this thesis introduces the TLP briefly,such as its development history,the composition,main types and characteristics,after the briefly introduction,the main contents in this thesis are as follows:First,established numerical simulation model by using the software of AQWA-LINE,then calculate the CTLP’s wave frequency responses in frequency domain in the condition of free floating.Second,choosing one hundred year return period extreme condition in South of China sea,then established numerical simulation model of the coupling system by using the software of AQWA-NAUT and calculation the motion response performance in time domain.Taking the zero degree as an example,this thesis analyzes the influence of the low frequency and high frequency component.Besides,considering the condition of tendons’ rupture,when one tendon ruptured,analyze the coupled motion response of the CTLP in time domain.Third,considering the influence of the tendons with changeable diameter,change the tendons’ diameter in various depth,then established numerical simulation model of the coupling system by using the software of AQWA-NAUT and calculation the motion response performance in time domain.Then,two different assisted mooring system are studied to improve the performance of CTLP,one is taut mooring system,another is catenary mooring.The results show that frequency has a great influence on the add mass,radiation damping,RAOs;different environment loads angles also influent the RAOs a lot.when one tendon belong to different column reputed will lead to different motion response,generally,the response value will increased.Besides,the effective tension of the tendons will also increased.By changing tendons diameter in various depth,find the optimization of the tendon diameter and by using the assisted mooring system,the motion response of CTLP is improved obviously.