Simulação computacional da interação fluido-estrutura em bombas de cavidades progressivas

The pumping through progressing cavities system has been more and more employed in the petroleum industry. This occurs because of its capacity of elevation of highly viscous oils or fluids with great concentration of sand or other solid particles. A Progressing Cavity Pump (PCP) consists, basically, of a rotor - a metallic device similar to an eccentric screw, and a stator - a steel tube internally covered by a double helix, which may be rigid or deformable/elastomeric. In general, it is submitted to a combination of well pressure with the pressure generated by the pumping process itself. In elastomeric PCPs, this combined effort compresses the stator and generates, or enlarges, the clearance existing between the rotor and the stator, thus reducing the closing effect between their cavities. Such opening of the sealing region produces what is known as fluid slip or slippage, reducing the efficiency of the PCP pumping system. Therefore, this research aims to develop a transient three-dimensional computational model that, based on single-lobe PCP kinematics, is able to simulate the fluid-structure interaction that occurs in the interior of metallic and elastomeric PCPs. The main goal is to evaluate the dynamic characteristics of PCP s efficiency based on detailed and instantaneous information of velocity, pressure and deformation fields in their interior. To reach these goals (development and use of the model), it was also necessary the development of a methodology for generation of dynamic, mobile and deformable, computational meshes representing fluid and structural regions of a PCP. This additional intermediary step has been characterized as the biggest challenge for the elaboration and running of the computational model due to the complex kinematic and critical geometry of this type of pump (different helix angles between rotor and stator as well as large length scale aspect ratios). The processes of dynamic generation of meshes and of simultaneous evaluation of the deformations suffered by the elastomer are fulfilled through subroutines written in Fortan 90 language that dynamically interact with the CFX/ANSYS fluid dynamic software. Since a structural elastic linear model is employed to evaluate elastomer deformations, it is not necessary to use any CAE package for structural analysis. However, an initial proposal for dynamic simulation using hyperelastic models through ANSYS software is also presented in this research. Validation of the results produced with the present methodology (mesh generation, flow simulation in metallic PCPs and simulation of fluid-structure interaction in elastomeric PCPs) is obtained through comparison with experimental results reported by the literature. It is expected that the development and application of such a computational model may provide better details of the dynamics of the flow within metallic and elastomeric PCPs, so that better control systems may be implemented in the artificial elevation area by PCP

Análise do fluxo d’água na barragem Engenheiro Armando Ribeiro Gonçalves - Açu/RN

The solution of partial differential equation of seepage problems is difficult to find analytically, especially for situations that involve great complexity. To overcome this problem, software based on finite differences and finite elements are usually used. This work presents the use of a finite element software, the GEO5, to solve the seepage problem at a dam of very complex section, the dam Eng. Armando Ribeiro Gonçalves, which at the end of its construction suffered rupture of the upstream slope at the central dam and then went through a process of reconstruction and auscultation. The analyses were performed for the operating condition of the reservoir, with an established flow. A numerical model was developed based on the level readings of the reservoir water and their piezometric readings as a proposal for the evaluation and future behavior prediction of the dam on established flow conditions. The use of constitutive models with the aid of computer systems is reflected in a way to predict future risk situations so they can be prevented

Modelos de realizações discursivas nos benditos populares e nas novenas

With the purpose of contribute to the understanding of oral texts constituent processes, we seek, with this work, verify how formulaicity processes in the benditos and novenas , religious intangible heritage, are established. For this, we made an overview on the performance of repetitions which are established in the corpus collected for the study, considering the presence of Discourse Traditions in the analyzed texts. It is noteworthy that the corpus consists of benditos and novenas collected in the municipality of Lajes, Rio Grande do Norte. This material is part of the differential corpus of the Project for the History of Brazilian Portuguese (PHPB-RN). Regarding the theoretical framework used to guide the research, we based our analysis on Discourse Traditions (DTs) theoretical assumptions, with the ideas defended by Johannes Kabatek, besides taking into consideration the assumptions of Paul Zumthor about orality in popular religious texts, among other authors cited throughout the work. In the context of popular cultures, the existence of oral texts serves to various interactive objects and this is not different in popular benditos and novenas (cf. Sá Júnior, 2009). In this sense, focusing the gaze through Discourse Traditions (DTs), we can verify that the texts/discourses present discursive regularities or textual forms already produced by society, in earlier times, which remain or are modified throughout its existence, as shows Johannes Kabatek (2001, 2003, 2005 and 2006). Also in this sense, Paul Zumthor (1993) presents us the idea that talk about using "word" in memory, in its real sense, implies admitting it as something which has an immeasurable power, which is able to decide directions in world, and from that is established the "wealth of oral traditions"