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SPEAKER
COMPANY
TITLE OF PAPER
Alexey Babenko
Piping Systems Research & Engineering Co NTP (Truboprovod)
Flow distribution analysis of complex pipeline systems with two phase flow
Other Authors
Leonid Korelstein, Piping Systems Research & Engineering Co (NTP Truboprovod)
Abstract
Flow rate distribution analysis method for complex piping systems with gas-liquid two phase boiling/condensing flow was developed and implemented in Hydrosystem software. The method is an extension of Global Gradient Algorithm initially proposed for water piping systems analisys. The new feature is widely used for transfer pipelines in refineries and steam tracing systems in power industry.
Development of a numerical method for the solution of a heat conduction problem with nonstandard boundary conditions at calculation of heat change in thermal-insulating constructions with piping steam/water trace heating
Other Authors
Viktor Pocajt, JSC Giprogazoochistka
Abstract
A two-dimensional stationary heat exchange problem modeling the process of heating of the pipeline with the stopped product flow by steam/water trace on a requirement of maintenance of the given temperature of a product on all length the pipeline is considered. It is proposed to solve this problem approximately by replacing it by heat conduction 2D problem in circular (product) and annular (pipe) regions with 3rd type boundary conditions with different effective heat transfer coefficients on different parts of boundary. Effective engineering solution of the later problem was obtained using Fourier series.
The approximate problems solutions and results of computer model operation are compared and the suitability of the developed method for engineering problems is shown.
The use of acoustic techniques to detect water intrusion in submarine pipelines and monitor pipeline flooding part I – main operating and numerical aspects
Other Authors
Diana Magnabosco, EnginSoft SpA | Paolo Catena, Saipem SpA | Paolo Monti, Saipem SpA | Lorenzo Bucchieri, EnginSoft SpA
Abstract
The laying of submarine pipelines is an offshore operation that continues to be defined by its challenging technological features. Indeed, current projects may involve the installation of submarine pipelines along routes extending over hundreds of kilometres or at water depths in excess of 2000 m. Sometimes the two requirements are coupled.
While submarine pipelines are usually laid empty, water ingress cannot be excluded as a consequence of accidental events. Progressive pipeline flooding can represent a significant risk, both for pipeline operations and for the safety of the laybarge performing them. Consequently, both water ingress and the ensuing pipeline flooding need to be detected and tracked in real time in order to support the remedial actions implemented on board the laybarge.
Saipem has developed a tool, the Integrated Acoustic Unit (IAU), based on a non-invasive acoustic technology. The IAU is capable of localizing obstacles (e.g. pigs, inline items) or pipe deformations, and of detecting and tracking any intrusion of water through the measurement of the wave reflection it produces. Different numerical and analytical methods and softwares have been developed in-house to convert the acoustic wave reflection into a measurement of pipe obstruction or deformation and track pipeline flooding.
This paper first of all introduces the main operational aspects associated with the laying of submarine pipelines. These include the requirements for managing accidental events such as the water ingress and progressive pipeline flooding, and the use of the acoustic technology needed to detect and track any intrusion. It then discusses the numerical activities that support the detection of the water ingress and the tracking of the pipeline flooding from the measurement of the acoustic wave reflection.
The use of acoustic techniques to detect water intrusion in submarine pipelines and monitor pipeline flooding part II – dedicated CFD simulations
Other Authors
Paolo Monti, Saipem SpA | Lorenzo Bucchieri, EnginSoft SpA | Paolo Catena, Saipem SpA | Natalia Pierozzi, Saipem SpA
Abstract
The laying of submarine pipelines is an offshore operation that continues to be defined by its challenging technological features. Indeed, current projects may involve the installation of submarine pipelines along routes extending over hundreds of kilometres or at water depths in excess of 2000 m. Sometimes the two requirements are coupled.
While submarine pipelines are usually laid empty, water ingress cannot be excluded as a consequence of accidental events. Progressive pipeline flooding can represent a significant risk, both for pipeline operations and for the safety of the laybarge performing them. Consequently, both water ingress and the ensuing pipeline flooding need to be detected and tracked in real time in order to support the remedial actions being implemented on board the laybarge.
Saipem has developed a tool, the Integrated Acoustic Unit (IAU), based on a non-invasive acoustic technology (reflectometry). The IAU is capable of localizing obstacles (e.g. pigs, inline items) or pipe deformations, and of detecting and tracking any intrusion of water. The use of this acoustic technology to detect and track water intrusion is presented in a separate paper.
The efficiency of the technology can be heavily affected by the presence of laying tools in the pipeline, an obstacle that in turn can generate a spurious acoustic wave reflection, on the one hand, and muffle acoustic wave propagation throughout the pipeline, on the other.
This detrimental effect on the performance of the acoustic technology can be significant if a laying tool is located in proximity to the water ingress. In such cases, the tool can act as a “cork” for the water’s propagation, resulting in an additional obstacle for acoustic wave propagation which then further reduces the performance of the acoustic technology, potentially down to a level that makes its use totally ineffective.
This paper presents a CFD simulation which was performed to study water ingress in detail and to quantify additional obstacles to its propagation. Reference is made to a realistic pipelaying scenario and accidental event.
In the context of the safety reassessments of the French nuclear power plants following the Fukushima accident, it was decided to install a post-accident system that allows the residual power of the reactor building to be evacuated.
This evacuation is carried out by means of a tube exchanger with U-tubes, in which circulates the contaminated fluid which is cooled from water pumped directly into river or sea depending on the sites.
The exchanger must be able to operate continuously and completely safely for a whole year, and since the barrier between the contaminated fluid and the cold source is the bundle of tubes, each tube must remain mechanically resistant in order to ensure the leak tightness of this barrier.
The cold water which circulates inside the exchanger tubes, although filtered, remains charged with particles of sand with up to 300 ppm by mass, which causes erosion inside the tubes.
It is to evaluate the loss of thickness due to this erosion that this study is carried out using a CFD approach on a bent tube and in view of this loss of thickness, the integrity under pressure of the eroded tube is checked by a finite element analysis of it.
Leaf seal is a common sealing system in gas turbines and jet engines. One of its typical applications consists in creation of sealing between the combustion chamber and the first stage nozzle, while allowing their relative motions. This kind of sealing could be subjected to rupture due to dynamic phenomena triggered by chattering, which typically occurs once partial or total contact is lost between the leaf and one of the mating components, due to system kinematics and/or dynamics (acoustic pulsations, rotordynamics, transient fluid dynamics effects). At present the common practice in BHGE seal dynamic design is a trial and error approach based on direct system testing. The present research aims at investigating leaf seal dynamic response through numerical simulations and verifying the possible occurrence of chattering. With this scope a non linear dynamic analysis has been performed on the leaf seal connecting the inner liner to the annular combustion chamber of GE Nova LT16 gas turbine.
The analysis consisted in a sensitivity study of the seal dynamic response in time domain against different static delta pressures, friction coefficients and leaf seal inclinations. Analysis revealed that friction plays a fundamental role in system damping and that the stabilized conditions at impulsive excitation are representative of the response at cyclic excitation. Results also showed that the natural frequencies and the mode shapes of the leaf seal calculated through a detailed non linear approach for the stabilized conditions are the same as those computed through a simpler linear modal analysis, where actual contact status between the parts and static pre-stress are considered. Analysis also revealed that the first natural frequency of the leaf seal in all its operating and kinematic envelope is sufficiently higher than the forcing acoustic frequencies and therefore chattering does not occur whenever the contact (even partial) with nozzle and liner is being maintained.
Efficiency Assessment of Heat Exchangers with Gyroid Topology
Abstract
Minimal Surface Lattice structures based upon the gyroid topology have been one of nature's time-tested patterns. Callophrys Rubi butterflies and calcite particles use gyroids for light weight structural members. New in fill capabilities in ANSYS SpaceClaim and Additive Layer Manufacturing (ALM) empowers designers to create nature-inspired gyroid components. The nature of gyroid topology to separate the domain in two different independent spaces enables the generation of efficient heat exchangers. A model generation and the results of a CFD study of triply periodic gyroid heat exchangers will be presented.
Design optimization of a Free-Fall-Life-Boat (FFLB) using Fluid Structure Interaction and Kinematics analyses
Other Authors
George Korbetis, BETA CAE Systems | Dimitrios Drougkas, BETA CAE Systems
Abstract
The FFLBs are used for emergency evacuation from ships and offshore structures. It is of great importance to predict the behavior of such vessels at the early design stages and assure the proper function in hazardous conditions. Critical parameters such as, occupant’s acceleration, vessel’s strength and successful moving away from the accident area have to be considered during the design and verification process.
Combined CFD and FEA algorithms are used to analyze vessel’s behavior, where numerous iterations are needed to succeed convergence including interpolation of the dynamic loads from the CFD to the FEA. However, the use of an FSI algorithm can acquire results much faster and thus the design optimization can become a realistic and cost effective approach.
In this paper, a case study of a FFLB analysis is presented using an FSI solver while a Kinematic solver calculates the initial conditions of the FSI analysis for different initial positions of the vessel.
Alessandro Pizzoferrato, SUPSI - DTI - MEMTi | Viola Becattini, ETH Zürich | Andreas Haselbacher, ETH Zürich | Giw Zanganeh, ALACAES | Maurizio C. Barbato, SUPSI - DTI - MEMTi
Abstract
Electric energy storage is becoming of paramount importance for the future. A viable alternative to pumped hydro plants, in terms of both power and energy storage capacity, is given by Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) plants. These systems can store electric energy via thermal and mechanical energy storage. In fact, electric energy feeds a motor that runs a compressor; the high-pressure hot air obtained is cooled with a thermal energy storage (TES) and than stocked into a cavern. When electric energy is requested by the grid, the high-pressure air is extracted from the cavern, heated passing through the TES and than expanded into a turbine-generator power block.
A Matlab-Simscape model was developed to simulate the dynamic behaviour of AA-CAES plants. Temperature dependent air properties, efficiency maps for turbomachinery and realistic power ramps were implemented. Moreover, the model is coupled with a 1D Fortran code, which models the detailed dynamics of a packed-bed TES. Model validation against experimental data and performance simulation for a full scale plant working for a typical week are presented.
CFD analysis of an industrial burner for a regeneration gas heater application
Other Authors
Thomas Odry, Brembana & Rolle | Marco Rottoli, Brembana & Rolle | Annarosa Troia, EnginSoft
Abstract
Burners are widely used to satisfy the request of thermal energy in many industries. The design of a burner and the related heat transfer equipment must fulfill severe safety requirements, in order to avoid issues during the operation stage. One of the risk is that the flame can impinge onto tubes or other part of the equipment, with consequent safety issues. In the oil and gas industry, some fired equipment design practices dictate the maximum flame length with respect to the size of the radiant chamber. Flame length is usually determined by performing a dedicated firing test, but CFD can be conveniently used for this purpose. The present work describes a numerical analysis of a gas-fired burner in a vertical cylindrical fired heater. Starting from the 2D drawing, a 3D model of the burner and the radiant section of the heater was created and meshed with ICEM CFD. The solver ANSYS CFX was used to run the simulation. The analysis was developed in cooperation with Enginsoft, especially in the development of the 3D model and meshing stage. Different load conditions of the burner have been tested, in order to check the flame height at different conditions.
Prediction of the overall performance of a centrifugal pump by means of a CFD simulation
Other Authors
Bruno Schiavello, Flowserve | Davide Pirola, Flowserve
Abstract
Centrifugal pumps are the most commonly used in different industrial fields like power generation, oil & gas, chemical plants, desalination, pipeline, water treatment, agriculture, automotive, aerospace, and domestic applications. On the other hand, centrifugal pumps are a very complex type of turbomachines in which mechanical energy is converted into pressure energy by means of blades action and angular momentum change. The design of a large size centrifugal pump with conflictual requirements from customized specifications is a hard engineering challenge. To design and develop a centrifugal pump, it is very important to have a long experience and ability to predict the final performance with good accuracy. The design can be very complex because the flow in a centrifugal pump is turbulent, three dimensional and time-dependent. The primary purpose of this paper is to show a comparison between numerical analysis performed by means of a commercial code and the experimental results obtained during the testing phase of a very large in-line centrifugal pump, including suction casing – double suction impeller – double volute – discharge branch diffuser. The key focus will be in the comparison between test measurements and numerical results in term of overall performance (head, power and efficiency) as verification and validation of the CFD simulation for future applications.
Cone-meter performance optimisation through a CFD-experimental approach
Other Authors
Marco Bertoli, Astarte Strategies S.r.l. | Antonio Landi, Bono Energia S.p.A. | Gianluca Marongiu, Dipartimento di Ingegneria Meccanica, Chimica e dei Materiali (DIMCM)| Francesco Cambuli, Astarte Strategies S.r.l. and Dipartimento di Ingegneria Meccanica, Chimica e dei Materiali (DIMCM)
Abstract
V-cone flow meters are widely adopted due to their many advantages, as a wide rangeability, low sensitivity to vibration and are suitable for many types of fluids and two-phase flows.
The actual reference standard prescribes geometric, installation and operating procedures for V-cone meter measurements in ducts and calibration instructions with specific ranges of main geometric and operating parameters.
To overcome the limitations of the standard and better adapt the geometry to the requirements of an industrial application, a design optimization of a V-cone meter has been done through a combined numerical and experimental approach. The numerical model has been validated against wind tunnel tests on a scale model. A CFD analysis on the modified-to-standard configuration leaded to the calibration relation of the measuring device. Results have shown a good accuracy of the calibration formulas and an appreciable rangebility of the cone meter in the proposed configuration.
Wettability models in pool boiling numerical simulation
Other Authors
Marco Marengo, University of Brighton | Anastasios Georgoulas, University of Brighton | Joël Joël De Coninck, Laboratoire de Physique des Surfaces et Interfaces
Valve CFD comparison between ANSYS CFX and CONSELF
Other Authors
Roberta Messina, Tecnohit | Fabio Zanoletti, Tecnohit
Abstract
INTRODUCTION In recent years and thanks to cloud computing development, a certain number of companies are proposing tools to simulate directly from your own browser using remote hardware resources. In many cases, these tools are user-interfaces that allows an easy management of open-source software such as OpenFOAM. As one may expect, given the popularity of both CFX and OpenFOAM, many comparisons already exists such as [1], [2] and [3]. Beside this, given the high number of users of OpenFOAM there are comparisons between OpenFOAM with experimental results, such as [4].
In the abovementioned tools, the presence of a user-interface actually limits the choices available in standard OpenFOAM in terms of boundary conditions and numerical schemes in particular, rising a new need of results validation for these modern tools.
SOFTWARE The software used for the current comparison are ANSYS CFX v18.1 and CONSELF v2.9.2, one of the abovementioned cloud providers based on CFD solver OpenFOAM v4.1.
GEOMETRY AND MESH The geometry considered is a simple bulb valve where pressure drop calculation is the main simulation drive. Given the geometry in STEP format two different meshes have been defined for the two solvers. With the possibilities offered by both systems, parameters were chosen in order to produce a similar quality mesh in both cases. A tetrahedral meshing algorithm has been chosen, with boundary layer treatment in both cases (5 layers with a first wall height of 8.0E-4 m) calculated to maintain y+ in the acceptable range for the used turbulence model. Mesh surface dimension is 2.0E-3 m, resulting in about 1 million elements in both configurations.
CFD ANALYSIS The CFD analysis is an incompressible steady flow at Re ⋍ 100 000. Four different boundaries are applied according to the following scheme: velocity inlet, pressure outlet, symmetry and wall. Turbulence is taken into account using a standard k-ε model [5]. In order to reduce as much as possible the boundaries effects on the valve results, inlet and outlet boundaries are placed at least 5 times farther than dh - hydraulic diameter.
NUMERICAL SCHEMES The main difference between the two simulation software used is the numerical schemes used. CONSELF, based on OpenFOAM, can be described as a collocated software where variables are solved in segregated way with a SIMPLE pressure-velocity coupling is implemented [6]. From the numerical point of view, gradient reconstruction is computed using a linear Gauss hypothesis, whilst the convective schemes uses a second order linear-upwind scheme, bounded to improve stability. Viscosity flows are limited, for the sake of stability, not to exceed the orthogonal contribution. From the algebraic point of view, two solvers are used: algebraic multi-grid for the continuity equation and Gauss-Seidel for all the other variables. CFX is a pressure-velocity coupled software. The reconstruction of the gradient term is computed using finite-element-shape functions. The convective term is computed using the High-Resolution-Scheme [7], that is a bounded scheme.
As said before, the main global result to be considered in the simulation is the pressure drop, calculated as the difference of static pressure at the inlet and at the outlet. Given this global parameter, further investigation on local variables are considered, such as pressure and velocity across the valve.
ANSYS CFX | CONSELF OPENFOAM - 922.38 | 1156.38
EXTRA CONTENTS IN FINAL PAPER The final paper is going to provide further details beside those here reported. A more advanced mesh comparison (also in terms of mesh quality, skewness and orthogonality) is necessary to provide a general overview of the results. Extra results post-processing will be provided in terms of graph comparisons, extracting velocity profiles at different locations.