Rigid Jumper Research Articles

Theoretical and CFD modelling of single and slug oil, water and gas flows in a deepwater rigid jumper

Theoretical and CFD modelling of single and slug oil, water and gas flows in a deepwater rigid jumper

Research on the lightning shielding performance of strained angled tower for the [formula omitted]1100 kV UHVDC transmission project

Rigid jumper is usually used in the strained angled tower for the UHV transmission project, which makes the protection angle of the ground wire to the jumper end larger, thus the lightning shielding failure risk of the strained angled tower may increase. In order to study the lightning shielding performance of strained angled tower for the ±1100 kV ultra-high voltage direct current (UHVDC) transmission project, a numerical model for the simulation of lightning attachment to the strained angled tower was established based on the research results in the aspects of lightning downward leader, inception and propagation characteristic of upward connecting leader and so on. The maximum lightning shielding failure current and the shielding failure flashover rate (SFFOR) of rigid jumper were calculated under different line angles and overhead ground wire cross-arm lengths based on the proposed model. Results show that the lightning flashover of rigid jumper mainly occurs on the outer side while the rigid jumper on the inner side is in a good shielding state. When the cross-arm length of overhead ground wire on the outer side of J27104A1 tower with 90° line angle is greater than 21.7 m, the SFFOR of rigid jumper will be below 0.1 times/(100 km a), which can meet the operation requirement. The analysis provides technical references for the lightning protection design of strained angled tower for the UHVDC transmission project.

Fatigue Damage Assessment to a Rigid Planar Jumper on Model Scale

A rigid jumper is an important part of a subsea production system, and it may experience significant vortex-induced vibrations (VIVs) if subjected to current. It has normally a non-straight geometry shape in three-dimensional space. Consequently, the response of a rigid jumper under VIVs is much more complicated compared with straight pipeline structures. Currently, there are very limited studies and design guidelines including methods on how to assess the fatigue damage of rigid jumpers under VIVs. The methodology used for straight pipelines is often applied by ignoring the non-straight geometry characteristics and the multiaxial stress states. However, both experimental and numerical results show that the torsional stress does exist besides the flexural stress for rigid jumpers under VIVs. The objective of this study is to do a fatigue assessment practice based on the state-of-the-art calculation methods to a rigid jumper on model scale. The VIV response is obtained from experimental tests and numerical calculations by either force or response model methods. The influence of torsional stress on fatigue assessment is studied. Two approaches have been investigated. In the first approach, the flexural and torsional stresses are evaluated separately. The second approach uses the first principal stress to calculate the fatigue damage; thus, the flexural and torsional stresses are evaluated together. It appears that the use of the first principal stress gives higher fatigue damage if the torsional stress contribution is significant. Furthermore, the principal stress method is also less time-consuming in processing the results.

Crucial issues for deep water rigid jumper design

Subsea Rigid Jumpers (SRJ) are used in Ultra Deep Water (UDW) projects to connect well heads, manifolds and riser bases with Intra-field and Export Pipeline End Terminations. Short and flexible pipe sections are assembled in a variety of spatial configurations to accommodate fabrication and installation tolerances (design for installation) and to withstand the end loads and displacements caused by flow/temperature and pressure fluctuations, as well as riser base oscillations (design for operation).Two main criticalities are recognised in Subsea Rigid Jumper design: the bending strength and deformation capacity of induction bends during installation and operation; and the fatigue resistance under the cyclic loads from flow fluctuations and dynamic response to environmental loads.The scope of this paper is twofold: 1) to present the FE model developed to quantify the strength and deformation capacity of induction bends subject to typical deep water installation and operational loads; 2) to describe how the Vortex Induced Vibrations phenomenon in complex 3D Subsea Rigid Jumpers can be treated to assess the fatigue damage at potential stress intensification. Both issues are pertinent to Subsea Rigid Jumper design, at the moment partially covered by specific project/company guidelines.

Design Parameter Characteristics in a Subsea Rigid Jumper

Functionally, subsea jumpers in a short pipe connector are used to transport production fluids between two subsea components such as a tree and manifold, manifold and manifold or manifold and export sled. In the design of a rigid jumper system, all parts of the system should be analyzed with respect to reliability, safety, costs and expected failure rates and to minimize failures and maintenance for the life of the design. Rigid jumpers are standard shaped pipes that can withstand high static and dynamic loads generated by internal pressure, temperature and external fluid effects. This paper describes a fluid structure interaction modeling technique that incorporates all of the significant behavioral effects that influence the thermal and geometric characteristics of jumpers for operating, hydraulic and service fluids. The use of nonlinear finite element code allowed the creation of a jumper model of a coupled fluid structure interaction problem. The results and recommendations presented in this paper will provide assistance to the industry in the design and analysis of subsea jumpers.

Simplified Biomechanics for a Possible Explanation of the Ancient Greek Long Jump Using Halteres

In this paper closed form analytical expressions were derived in order to simulate the possible action of halteres used in the ancient Greek long jump. For the sake of simplicity, elementary theory of rigid body dynamics is used, which however is capable of simulating the motion of a hypothetical rigid jumper for whom the Cartesian components of the initial velocity at the take-off and the angular velocity of rotating arms are prescribed. Particular attention is paid on the initial position and the direction of arms' rotation as well as on the role of the amount of masses due to the halteres. It was found that if at the take-off the upper limbs are upwards, also rotate forwards, whereas at the landing they are almost downwards, the length of the jump increases as the weight of the halters.