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Liu Y.-X.,China University of Petroleum - East China | Wang H.-X.,China University of Petroleum - East China | Wang M.,Shengli Engineering and Consulting Company Ltd
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2012

In order to simulate local scour around submarine pipelines, a two dimensional model based on k-ε turbulence model was proposed. The changes of flow field, seabed pressure and shear force were simulated by changing flow velocity and impending quantity. The results show that the local scour is more likely to occur with flow velocity increasing. Three vortexes emerge when impending quantity is less than zero, and there is only one vortex when impending quantity is greater than zero. The larger impending quantity, the greater the scour rate when the impending quantity is less than zero. The scour rate is weaker with impending quantity increasing when there is no contact between submarine pipelines and seabed. Source


Yang X.-P.,China University of Petroleum - East China | Lu S.-J.,China University of Petroleum - East China | Lu S.-J.,Shengli Engineering and Consulting Company Ltd | Gao Z.-F.,Xinwen Mining Group Co. | And 2 more authors.
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2010

The amine solution is characterized by quick absorption, large absorption capacity and simple regeneration. The potentiometry method and pH method were used to study carbon dioxide absorption characteristics in MEA, DEA and TEA solution. The relations among electric potential, pH, absorption rate, absorption capacity were studied. The new measurement methods about amine solution concentration and carbon dioxide concentration were presented. The results show that MEA and DEA are good amine solutions.Also after drawing the relation curve between absorption rate and potentiometry or absorption rate and pH, the potentiometry method (or pH method) can be used to analyze the absorption extent of CO2 in amine solutions. Source


Yang X.-J.,China University of Petroleum - East China | Xiu Z.-X.,China University of Petroleum - East China | Yan X.-Z.,China University of Petroleum - East China | Feng Y.-X.,Shengli Engineering and Consulting Company Ltd
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2010

The complicated system decision problem for design scheme optimization of deep water jacket platform was analyzed. The four initial design schemes with different structure types were proposed. The optimal structure design parameters for each scheme were obtained by optimum design method, in which the nominal fatigue reliability index of structure system obtained by spectral method was taken as a key constraint condition. According to the optimized structural performance parameters, the factors which had effects on the type selection of deep water jacket platform were comprehensively considered. The objective weight and relative membership degree for each factor were obtained by binary comparison method. Finally, the three-level fuzzy optimum decision method was used for the fuzzy optimization. A deep water jacket platform for 200 m was taken as an example. The results show that the optimal performance parameters obtained by optimization analysis of initial design schemes can give accurate quantitative indexes and the fuzzy factors are reduced compared with the conventional methods. The method is more beneficial to obtain the reasonable evaluation of deep water jacket platform. Source


Yang X.-J.,China University of Petroleum - East China | Yan T.,China University of Petroleum - East China | Xiu Z.-X.,China University of Petroleum - East China | Yan X.-Z.,China University of Petroleum - East China | Feng Y.-X.,Shengli Engineering and Consulting Company Ltd
Gongcheng Lixue/Engineering Mechanics | Year: 2011

The process of a submarine pipeline impacted by dropped objects is simulated by using a nonlinear dynamic finite element method. The Ramberg-Osgood model is adopted to model the seabed and the different tensile and compressive nonlinear characteristics of concrete coating are considered at the same time. The interactions between the dropped object and seabed and pipeline are solved with the penalty function method. The influence of various factors on the plastic impact deformations of the pipeline are analyzed, including the object shape, impact angle, friction, internal pressure, concrete thickness, burial depth and free spanning of the pipeline. The results show that: the dropped object impacting the pipeline with a tip makes a larger dent depth, but a relatively small deformation range; the maximum dent depth of the pipeline occurs at an impact angle of 90° and friction makes little influence on the impact; the internal pressure increases the stress of the pipeline, but decreases the dent depth; concrete coating has a weak protective effect when the weights of dropped objects are larger; the pipeline can be effectively protected, when the buried depth was more than one meter; the free spanning decreases the dent depth of the pipeline but makes the integral damage of the pipeline more easily. The method in the paper is more suitable to the actual situation, comparing with the results obtained by the current codes. Source


Chen J.-L.,China University of Petroleum - East China | He L.-M.,China University of Petroleum - East China | Luo X.-M.,China University of Petroleum - East China | Lu Y.-L.,China University of Petroleum - East China | And 2 more authors.
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2013

Differential Reynolds stress model was used to simulate rotating vortex core boundary of gas phase flow field in cylindrical cyclone separator. The attenuation form of vortex core was expounded and the effects of vortex finder diameters, inlet areas and separator lengths on the distribution of rotating vortex core boundary were studied. The results show that zero axial velocity boundary and rotating vortex core boundary are different, which locate on both sides of vortex finder projection surface respectively. The natural termination form of rotating vortex core in separator is that vortex core end stops deviously on the wall of separator and makes circular motion along the wall. Vortex core boundary width decreases with the decrease of vortex finder diameters and the increase of inlet areas. Vortex core boundary in separator with small length presents columnar distribution approximatively among the larger span of vortex finder diameters distribution. The increase of separator length can make tangential velocity attenuate, and vortex core boundary expands outwards at vortex finder inlet and shrinks downwardly along the axial direction. Source

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