The general layout of 6 th generation semi-submersible drilling platforms is the main factor impacting the efficiency of their drilling operations. This paper provides a compound/integrated algorithm based on process flow that is aimed at improving efficiency, while giving attention to stability and safety at the same time. The paper describes the process flow of dual drilling centers and a hierarchical division of rigs based on the different modes of transportation of various drilling support systems. The general layout-centripetal overall arrangement spatially was determined based on drilling efficiency. We derived our modules according to drilling functionality; the modules became our basic layout units. We applied different layout algorithm to mark out the upper and lower decks. That is, the upper deck was designed based on the lowest transportation cost while the lower deck's calculations were based on the best-fit scope. Storage configurations in columns and pontoons were also considered for the layout design. Finally the center of gravity was taken into consideration and the general layout was adjusted accordingly, to result in an optimal center of gravity. The methodology of the general layout can provide a reference for implementation of domestic designs of semi-submersible rigs.
PurposeThe purpose of this paper is to study the effects of operating conditions including process coefficient, lubricant viscosity and cavitation pressure on the cavitation of spiral groove liquid-film seal (SG-LFS).Design/methodology/approachA mathematical model of SG-LFS is established based on the JFO boundary and a relative density is introduced. The universal governing equation after a coordinate transformation is discretized by the FVM method and solved by the Gauss-Seidel relaxation scheme.FindingsThe results indicate that the two-dimensional size of cavitation and cavitation degree are affected significantly by the process coefficient and lubricant viscosity but the effect of cavitation pressure can be ignored.Originality/valueThe effect mechanisms of operating conditions on the cavitation of SG-LFS are studied by the JFO boundary and cavitation degree characterized by a relative density. The results presented are helpful to perfect and deeply understand the cavitation mechanism of liquid-film seal.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0083/
Based on the planetary gear mechanism which realizes the three-leaf rose line drawing method, the ratio of the number of teeth of the sun gear, the planetary gear, the internal gear, and the length of the tracing rod are deduced. The calculation formulas of the number of teeth and the length of the tracing rod for drawing rose lines of any leaf are obtained. SolidWorks is used for modeling and dynamic simulation. The simulation results show that the conclusion is correct.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.