SIMULATION OF VISCOUS MEDIA SPATIAL FLOWS IN THE SYSTEM OF CHANNELS WITH SECTIONS OF COMPLEX FORM JUNCTIONS

Abstract

Relevance of the research is determined by the need to analyze the features of the workflow in machines with junctions of arbitrary geometry, combining/separating the flows of viscous media, in order to accurately and carefully predict the contingencies of their functioning due to the expressed thermal and dynamic loads caused by the effects of separation, detachment, pressure, the evolution of the structure of complex, shear, non-isothermal internal flows when at contact with the wall; reasonable choice, taking into account the possibilities of modern computing technology, the most natural approach of studying the spatial and unsteady nature of flows in these technical systems. The aim of this paper is to understand the problems of the modern level of research of flows in T-shaped channels, which are one of the main elements of technical equipment in the oil and gas industry; to establish the value of the existing results of experimental and theoretical analysis of complex shear flows in order to improve methods that contribute to an increase in the operational and structural level of the devices under high dynamic and thermal loads; to define the data for verification of models capable of more reliably predicting features of currents and heat and mass transfer in pipes; to give recommendations to the practice of calculating reliability of devices with T-shaped sections. Methodology: complex theoretical and experimental methods of analysis of hydrodynamics and heat and mass transfer at viscous-inertial laminar and turbulent flows of hydrocarbon drop and gaseous viscous media in internal systems with T-connections of the main and branch pipe. Results. The authors have carried out a critical review of modern data, modeling methods and models of studies of hydrodynamics and heat exchange processes when mixing drip and gaseous flows in elements of pipeline networks in a wide range of changes in mode and geometric parameters (T-connections, symmetrical/asymmetric expansion, Re=102…107, M<0,3...0,7). The paper presents the features that form the structure of currents in individual elements of equipment used in the oil and gas industry (crane assembly bindings). It was found that rounding of connection angles can reduce energy loss in branch pipe by 10–20 %. Details of vortex structure changes were analyzed by visualization/contactless recording methods. A classification of structures useful in formulating edge problems in mathematical modeling of processes at the Petroleum and Gas Devices is given. It is noted that the use of wall functions for modeling flows in T-connections can lead to an erroneous assessment of the level of pulsations of temperature and dynamic fields in wall regions. It is emphasized that the disengagement of flows, the growth of energy stress in local sections of the connection are sensitive to the nature of convective-diffusion interaction of momentum, heat transfer processes, separation, connection, local acceleration/braking mechanisms, turbulization of flow in wall regions. These features can be successfully predicted by modern models that take into account the specifics of flows with heterogeneous anisotropic turbulence. In conclusion, recommendations are given on prediction of local and integral properties of mixed flows, as well as problems having fundamental and applied significance that make up the subject of promising research.

Keywords

• channels
• t-junctions
• streams
• turbulence
• non-isothermicity
• models
• methods
• modeling
• structure
• regularities