Modeling of Heat Loss from Offshore Buried Pipeline through Experimental Investigations and Numerical Analysis

2016 ◽  
Author(s):  
Suvra Chakraborty ◽  
Vandad Talimi ◽  
Yuri Muzychka ◽  
Rodney McAffee
Keyword(s):  
Numerical Analysis ◽  
Heat Loss ◽  
Experimental Investigations ◽  
Buried Pipeline

Thermal Analysis of Offshore Buried Pipelines Through Experimental Investigations and Numerical Analysis

2016 ◽  
Author(s):  
Suvra Chakraborty ◽  
Vandad Talimi ◽  
Mohammad Haghighi ◽  
Yuri Muzychka ◽  
Rodney McAffee
Keyword(s):  
Numerical Analysis ◽  
Heat Loss ◽  
Transient Response ◽  
Oil And Gas ◽  
Burial Depth ◽  
Fluid Temperature ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Arctic Regions ◽  
Backfill Soil

Modeling of heat loss from offshore buried pipelines is one of the prime concerns for Oil and Gas industries. Offshore Oil and Gas production and thermal modeling of buried pipelines in arctic regions are challenging tasks due to environmental conditions and hazards. Flow properties of Oil and Gas flowing through the pipelines in arctic regions are also affected due to freezing around pipelines. Solid formation in the production path can have serious implications on production. Heavy components of crude oil start to precipitate as wax crystal when the fluid temperature drops. Gas hydrates also form when natural gas combines with free water at high pressure and low temperature. Pipeline burial and trenching in some offshore developments are now one of the prime methods to avoid ice gouge, ice cover, icebergs, and other threats. Long pipelines require more thermal management to deliver production to the sea surface. Significant heat loss may occur from offshore buried pipelines in the forms of heat conduction and natural convection through the seabed. The later can become more prominent where the backfill soil is loose or sandy. The aim of this paper is to provide an insight of modeling and conducting the experiments using different parameters with numerical analysis results support to investigate the heat loss from offshore buried pipelines. This paper also provides validation of the outputs from benchmark tests with analytical models available for theoretical shape factor at constant temperature and constant heat flux boundary conditions. These theoretical models have limitations such as the assumption of uniform soil properties around the buried pipeline, isothermal outer surface of the buried pipeline and soil surface. Degree of saturation of surrounding medium can play a significant role in the thermal behavior of fluid travelling through the backfill soil. This paper presents several steady states and transient response analysis describing some influential geotechnical parameters along with test procedures and numerical simulations using CFD to model the heat loss for different parameters such as burial depth, backfill soil, trench geometries etc. This paper also shows the transient response for several shutdown (cooldown) tests performed in the saturated sand medium. The statistical and uncertainty analysis performed from the experimental outputs also ensure the legitimacy of the experimental model. The outcomes of this research will provide valuable experimental data and numerical predictions for offshore pipeline design, heat loss from buried pipelines in offshore conditions, and efficient model to mitigate the flow assurance issues e.g. wax and hydrates.

scholarly journals Fish Cells, a new zero Poisson’s ratio metamaterial—Part I: Design and experiment

2020 ◽  
Vol 31 (13) ◽  
pp. 1617-1637
Author(s):  
Mohammad Naghavi Zadeh ◽  
Iman Dayyani ◽  
Mehdi Yasaee
Keyword(s):  
Numerical Analysis ◽  
Numerical Model ◽  
Poisson’S Ratio ◽  
Structural Integrity ◽  
Structural Response ◽  
Poisson's Ratio ◽  
Experimental Investigations ◽  
Fish Cells ◽  
Force Displacement ◽  
Model Approach

A novel cellular mechanical metamaterial called Fish Cells that exhibits zero Poisson’s ratio in both orthogonal in-plane directions is proposed. Homogenization study on the Fish Cells tessellation is conducted and substantially zero Poisson’s ratio behavior in a homogenized tessellation is shown by numerical analysis. Experimental investigations are performed to validate the zero Poisson’s ratio feature of the metamaterial and obtain force–displacement response of the metamaterial in elastic and plastic zone. A detailed discussion about the effect of the numerical model approach and joints on the structural response of the metamaterial is presented. Morphing skin is a potential application for Fish Cells metamaterial because of the integration benefits of zero Poisson’s ratio design. The structural integrity of the Fish Cells is investigated by studying the stiffness augmentation under tension and in presence of constraints on transverse edges. Finally, geometrical enhancements for improved integrity of the Fish Cells are presented that result in substantially zero stiffness augmentation required for morphing skins.

Numerical analysis of a hybrid tubular and cavity air receiver for solar thermal applications

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sayuj Sasidharan ◽  
Pradip Dutta
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Analysis ◽  
Heat Loss ◽  
Solar Thermal ◽  
Heat Transfer Analysis ◽  
Receiver Design ◽  
Radiation Emission ◽  
Content Type ◽  
Thermal Receiver

Purpose This paper aims to deal with characterisation of the thermal performance of a hybrid tubular and cavity solar thermal receiver. Design/methodology/approach The coupled optical-flow-thermal analysis is carried out on the proposed receiver design. Modelling is performed in two and three dimensions for estimating heat loss by natural convection for an upward-facing cavity. Heat loss obtained in two dimensions by solving coupled continuity, momentum and energy equation inside the cavity domain is compared with the loss obtained using an established Nusselt number correlation for realistic receiver performance prediction. Findings It is found that radiation emission from a heated cavity wall to the ambient is the dominant mode of heat loss from the receiver. The findings recommend that fluid flow path must be designed adjacent to the surface exposed to irradiation of concentrated flux to limit conduction heat loss. Research limitations/implications On-sun experimental tests need to be performed to validate the numerical study. Practical implications Numerical analysis of receivers provides guidelines for effective and efficient solar thermal receiver design. Social implications Pressurised air receivers designed from this method can be integrated with Brayton cycles using air or supercritical carbon-dioxide to run a turbine generating electricity using a solar heat source. Originality/value The present paper proposes a novel method for coupling the flux map from ray-tracing analysis and using it as a heat flux boundary condition for performing coupled flow and heat transfer analysis. This is achieved using affine transformation implemented using extrusion coupling tool from COMSOL Multiphysics software package. Cavity surface natural convection heat transfer coefficient is obtained locally based on the surface temperature distribution.

Numerical Analysis of Multi-Layer Continuous Diffusion Furnace Door Gas Curtain

2013 ◽  
Vol 367 ◽  
pp. 462-465
Author(s):  
Sheng Cai Zhang ◽  
Gui Qin Li ◽  
Li Xin Lu ◽  
Peter Mitrouchev ◽  
Cheng Gang Wang
Keyword(s):  
Numerical Analysis ◽  
Heat Loss ◽  
Thermal Load ◽  
Gas Flow ◽  
Time Varying ◽  
Main Aspect ◽  
Temperature Zone ◽  
Furnace Temperature ◽  
Air Curtain ◽  
Reduce Heat Loss

Thermal load oozing out through the door is the main aspect of the temperature zone heat loss of continuous diffusion furnace. In this paper, multi-layer gas curtain is designed to seal the furnace door in order to reduce heat loss and ensure furnace temperature to meet requirements in regulation. The unsteady flow is presented to better reflect complex time-varying velocity and temperature of curtain gas. Flow and temperature field of continuous diffusion door with multi-layer air curtain are numerically analyzed by Renault model and experimentally tested. And the influence parameters are tuned and optimized based on the theoretic numerical analysis and experiment results.

scholarly journals Numerical analysis of the heat loss of stop valves of heat networks

2017 ◽  
Vol 110 ◽  
pp. 01067
Author(s):  
Vyacheslav Polovnikov ◽  
Anatolij Vergun ◽  
Vasilij Sergeenko
Keyword(s):  
Numerical Analysis ◽  
Heat Loss ◽  
Heat Networks

Numerical Analysis of the Influence of the Parameter of Ductility of Reinforcing Steel on the Behaviour of Narrow Three-Span Reinforced Concrete Slabs from the Point of View of Experimental Investigations

2015 ◽  
Vol 769 ◽  
pp. 133-138
Author(s):  
Mirosław Wieczorek
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Laboratory Tests ◽  
Numerical Models ◽  
Material Model ◽  
Point Of View ◽  
Experimental Investigations ◽  
Concrete Slabs ◽  
Building Structures ◽  
Reinforced Concrete Slabs

In the time of exploitation of building structures frequently situations do occur, in which due to failures they are exposed to much higher loads than originally predicted. The subject matter of the performed investigations and a numerical analysis are models of four narrow reinforced concrete slabs with the dimensions 7140×500×190 mm. The paper presents the results of the numerical analysis, the aim of which was to reflect and to provide detailed information about phenomena occurring in the course of laboratory tests. Numerical models were constructed according to the system ANSYS, applying volumetric elements SOLID65 and bars LINK8. In order to determine the relation σ-ε of steel an isotropic model of strengthening in the system ANSYS was used, constructed by Misses. The behaviour of concrete was represented by the material model Concrete. The parameters applied in the material models had been obtained in laboratory tests of the material. The paper quotes the results of calculations compared with the results obtained in laboratory tests.

scholarly journals Numerical analysis of heat transfer in air-water heat exchanger with microchannel coil

2019 ◽  
Vol 95 ◽  
pp. 02004
Author(s):  
Vladimir Glazar ◽  
Anica Trp ◽  
Kristian Lenic ◽  
Fran Torbarina
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Numerical Analysis ◽  
Flow Direction ◽  
Heat Fluxes ◽  
Experimental Investigations ◽  
Flow And Heat Transfer ◽  
Working Parameters

This paper presents numerical analysis of fluid flow and heat transfer in the heat exchanger with microchannel coil (MCHX). In accordance with previously published experimental results, 3D mathematical model has been defined and appropriate numerical simulation of heat transfer has been performed. Geometry and working parameters of cross-flow air-water heat exchanger with microchannel coil, installed in an open circuit wind tunnel and used in experimental investigations, have been applied in numerical analysis in order to validate the mathematical model. 3D model with air and water fluid flow and heat transfer domains has been used, as it gives more precise results compared to models that assume constant temperatures or constant heat fluxes on the pipe walls. Developed model comprised full length of air and water flows in the heat exchanger. Due to limitations of computational capacity, domain has been divided in multiple computational blocks in the water flow direction and then solved successively using CFD solver Fluent. Good agreement between experimentally measured and numerically calculated results has been obtained. The influence of various working parameters on heat transfer in air-water heat exchanger has been studied numerically, followed with discussion and final conclusions.

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