Corrosion Testing of a Subsea Motor and Stator Winding Insulation System

2015 ◽  
Author(s):  
Melissa Poerner ◽  
Jean-François Grignard ◽  
John Krahn ◽  
Lionel Duranty ◽  
Steven Galioto
Keyword(s):  
Gas Flow ◽  
Carbonic Acid ◽  
Liquid Mixtures ◽  
Insulation System ◽  
Safety Measures ◽  
Static Tests ◽  
Gas Processing ◽  
Process Gas ◽  
Set Up ◽  
Winding Insulation

In subsea applications, turbomachinery is subjected to severe gas and liquid mixtures. This is due to the fact that equipment installed on the ocean floor is severely limited. Typical gas/liquid separators and gas processing equipment are not used to clean the gas before it enters the turbomachinery. This means that the turbomachines can have multiphase mixtures and also corrosive gases such as hydrogen sulfide or carbonic acid (carbon dioxide and water) present in their flow streams among other contaminants. In many of these subsea applications, the electric motor driving the turbomachine is cooled using the process gas. Therefore the internals of the motor must withstand the attack of the corrosive mixtures and erosion with multiphase flow. A series of environmental static tests were conducted on a full scale subsea prototype motor to evaluate the performance of various materials when subjected to corrosive gas mixtures. These tests were conducted at various time intervals with different levels of pressure and temperature to simulate the conditions of a subsea environment gas flow. This paper reviews the test matrix and the test set-up used to conduct these tests. Also, it highlights the safety measures used to manage the inherent risks of testing with large quantities of corrosive and toxic gases mixtures and the different techniques that were implemented to follow the trends of the health of the insulation system.

The role of gas flow distributions on CO2 mineralization within monolithic cemented composites: coupled CFD-factorial design approach

2021 ◽  
Author(s):  
Iman Mehdipour ◽  
Gabriel Falzone ◽  
Dale Prentice ◽  
Narayanan Neithalath ◽  
Dante Simonetti ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Factorial Design ◽  
Material Properties ◽  
Gas Flow ◽  
Design Approach ◽  
Processing Conditions ◽  
Gas Processing ◽  
Co2 Mineralization

Optimizing the spatial distribution of contacting gas and the gas processing conditions enhances CO2 mineralization reactions and material properties of carbonate-cementitious monoliths.

Numerical Study of Methane and Air Combustion Inside Heat-Recirculating Combustors

2013 ◽  
Author(s):  
Yanxia Li ◽  
Zhongliang Liu ◽  
Yan Wang ◽  
Jiaming Liu
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Central Area ◽  
Small Scale ◽  
Inlet Velocity ◽  
Strong Convection ◽  
Simulation Results ◽  
Lean Fuel ◽  
Set Up

A numerical model on methane/air combustion inside a small Swiss-roll combustor was set up to investigate the flame position of small-scale combustion. The simulation results show that the combustion flame could be maintained in the central area of the combustor only when the speed and equivalence ratio are all within a narrow and specific range. For high inlet velocity, the combustion could be sustained stably even with a very lean fuel and the flame always stayed at the first corner of reactant channel because of the strong convection heat transfer and preheating. For low inlet velocity, small amounts of fuel could combust stably in the central area of the combustor, because heat was appropriately transferred from the gas to the inlet mixture. Whereas, for the low premixed gas flow, only in certain conditions (Φ = 0.8 ～ 1.2 when ν0 = 1.0m/s, Φ = 1.0 when ν0 = 0.5m/s) the small-scale combustion could be maintained.

A Study on the Lower Flanges Fracture of Endplate Bolted Connection

2006 ◽  
Vol 326-328 ◽  
pp. 983-986
Author(s):  
Hong Wei Ma ◽  
Chong Du Cho ◽  
Qiang Pan ◽  
Hyeon Gyu Beom
Keyword(s):  
Crack Length ◽  
High Stress ◽  
Transverse Load ◽  
Stress Fields ◽  
Finite Element Models ◽  
J Integral ◽  
Bolted Connection ◽  
Static Tests ◽  
Opening Mode ◽  
Set Up

The quasi-static tests on the endplate bolted connections of the new structure system consisting of SCC beam and CCSHRC column are briefly introduced in this paper. Meanwhile, the 3-D solid finite element models of the connections with pre-existing cracks in the lower flange’s high stress fields are set up by ANSYS. The material nonlinearities of concrete, steel and bars, together with the contact between the endplate and column surface are all considered in the model. With the transverse load applied on top of columns, the fracture parameters are calculated by APDL. The results indicate that the opening mode crack will happen mainly. When the pre-existing crack length is 2.50mm and the inter-storey drift is less than 6mm, the stress intensity factor values agree well with the converting values derived from J-integral and the crack tip fields are in elastic state. The J values are highly influenced by the pre-existing crack length, while seldom influenced by the concrete compression strength. Moreover, the J-integral have the trend to sharply increase when the pre-existing crack length is larger than 0.61mm, and the pre-existing crack will grow during loading when its length is larger than 1.35mm.

Experimental Inverstigations On the Pressure Fluctuations in the Sealing Gap of Dry Gas Seals with Embedded Pressure Sensors

2021 ◽  
Author(s):  
Jingjing Luo ◽  
Dieter Brillert
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Static Pressure ◽  
Pressure Sensors ◽  
Operating Conditions ◽  
Test Facility ◽  
Experimental Investigations ◽  
Mechanical Seals ◽  
Process Gas ◽  
Sealing Gap

Abstract Dry gas lubricated non-contacting mechanical seals (DGS), most commonly found in centrifugal compressors, prevent the process gas flow into the atmosphere. Especially when high speed is combined with high pressure, DGS is the preferred choice over other sealing alternatives. In order to investigate the flow field in the sealing gap and to facilitate the numerical prediction of the seal performance, a dedicated test facility is developed to carry out the measurement of key parameters in the gas film. Gas in the sealing film varies according to the seal inlet pressure, and the thickness of gas film depends on this fluctuated pressure. In this paper, the test facility, measurement methods and the first results of static pressure measurements in the sealing gap of the DGS obtained in the described test facility are presented. An industry DGS with three-dimensional grooves on the surface of the rotating ring, where experimental investigations take place, is used. The static pressure in the gas film is measured, up to 20 bar and 8,100 rpm, by several high frequency ultraminiature pressure transducers embedded into the stationary ring. The experimental results are discussed and compared with the numerical model programmed in MATLAB, the characteristic and magnitude of which have a good agreement with the numerical simulations. It suggests the feasibility of measuring pressure profiles of the standard industry DGS under pressurized dynamic operating conditions without altering the key components of the seal and thereby affecting the seal performance.

scholarly journals Simulation of Thermoplastic Powder Cold Spraying

2021 ◽  
Vol 14 (6) ◽  
pp. 726-734
Author(s):  
Tatyana A. Brusentseva ◽  
◽  
Vladislav S. Shikalov ◽  
Sergei M. Lavruk ◽  
Vasily M. Fomin
Keyword(s):  
Gas Flow ◽  
Experimental Studies ◽  
Cold Spraying ◽  
Deposition Efficiency ◽  
Powder Materials ◽  
Stagnation Temperature ◽  
Computational Domain ◽  
Ansys Fluent ◽  
Process Gas ◽  
Spray Method

The work is devoted to the deposition of composite powder materials by cold spray method. As a spraying material, a thermoplastic compound «WAY» for marking the roadway was used. An asphalt concrete was used as a substrate. As a result of experimental studies, the dependence of the deposition efficiency on the stagnation temperature of the working air in the ejector nozzle was obtained. The ANSYS Fluent package was used for evaluative modeling of the cold spraying process. Gas flow patterns were obtained in the computational domain without particles and taking into account the interaction of the flow with particles. The trajectory of the particles was calculated for various spraying parameters

The Effects of Vibration and Pulsation on Metal Removal by a Plasma Torch

1973 ◽  
Vol 95 (2) ◽  
pp. 240-245 ◽  
Author(s):  
G. T. Dyos ◽  
J. Lawton
Keyword(s):  
Molten Metal ◽  
Gas Flow ◽  
Metal Removal ◽  
Capillary Waves ◽  
Plasma Jets ◽  
Removal Rates ◽  
Workpiece Vibration ◽  
Arc Current ◽  
Set Up ◽  
Gas Pulsations

An experimental study has been carried out on the effects of workpiece vibration and gas pulsations on metal removal rates using plasma jets. In the case of workpiece vibration, increases in removal rates of up to 30 percent were found, which can be accounted for in terms of capillary waves set up in the melt. The influence of pulsation of gas flow velocity and arc current at modulation levels of 10 percent was found to be negligible. A theoretical model has been developed which explains the results in terms of the development of resonance capillary waves in the molten metal and predicts the average depth of the layer of molten metal.

scholarly journals Experimental and Numerical Study of a Thermal Expansion Gyroscope for Different Gases

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 360 ◽  
Author(s):  
Guillaume Kock ◽  
Philippe Combette ◽  
Marwan Tedjini ◽  
Markus Schneider ◽  
Caroline Gauthier-Blum ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Gas Flow ◽  
Numerical Study ◽  
Rotational Velocity ◽  
Measurement Range ◽  
Gas Temperature ◽  
Hot Air ◽  
Working Principle ◽  
Set Up ◽  
Different Gases

A new single-axis gas thermal gyroscope without proof mass is presented in this paper. The device was designed, manufactured and experimentally characterized. The obtained results were compared to numerical simulation. The working principle of the gyroscope is based on the deflection of a laminar gas flow caused by the Coriolis effect. A bidirectional hot air flow is generated by alternating activation of two suspended resistive micro-heaters. The heated gas is encapsulated in a semi-open cavity and the gas expands primarily inside the cavity. The thermal expansion gyroscope has a simple structure. Indeed, the device is composed of a micromachined cavity on which three bridges are suspended. The central bridge is electrically separated into two segments enabling to set up two heaters which may be supplied independently from each other. The two other bridges, placed symmetrically on each side of the central bridge, are equipped with temperature detectors which measure variations in gas temperature. The differential temperature depends on the rotational velocity applied to the system. Various parameters such as the heating duty cycle, the type of the gas and the power injected into the heaters have been studied to define the optimal working conditions required to obtain the highest level of sensitivity over a measurement range of around 1000°/s. The robustness of the device has also been tested and validated for a shock resistance of 10,000 g for a duration of 400 µs.

Temperature Facilitated ECR-Etching for Isotropic SiC Structuring

2010 ◽  
Vol 645-648 ◽  
pp. 849-852 ◽  
Author(s):  
Florentina Niebelschütz ◽  
Thomas Stauden ◽  
Katja Tonisch ◽  
Jörg Pezoldt
Keyword(s):  
Substrate Temperature ◽  
Gas Flow ◽  
Electron Cyclotron Resonance ◽  
Three Dimensional ◽  
Etching Process ◽  
Free Standing ◽  
Working Pressure ◽  
Isotropic Etching ◽  
Set Up ◽  
Ar Gas

In order to realize complex three dimensional or free standing structures on SiC substrates, an undercut, i.e. a selective isotropic etching process of SiC, is required. This was realized using an electron cyclotron resonance etching set up with pure SF6 and a SF6/Ar gas composition at elevated substrate temperatures. Above 350°C a significant lateral etch component was observed, which rose to a value of 50-70 nm/min increasing the substrate temperature up to 570°C during the etching process. Depending on substrate temperature the etching profiles and surface roughness were studied. Based on an analysis of the influence of microwave power, working pressure, bias voltage, gas flow and gas mixture on the etching behavior a novel isotropic, high selective, residue free etch process for SiC was developed, which allows for example the fabrication of piezoelectric actuated AlGaN/GaN resonators grown on SiC substrates.

Computational Studies for the Exhausted Flue Gas

2005 ◽  
Author(s):  
V. C. S. Ferreira ◽  
C. S. S. M. Cordeiro ◽  
J. W. Kaehler
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Simulation Analysis ◽  
Thermal Power ◽  
Computational Studies ◽  
Rio Grande Do Sul ◽  
High Concentration ◽  
Abrasive Particles ◽  
Set Up ◽  
Technical Solutions

Pulverized coal with low average heating, producing ashes with high percentage of silica, is fired inside the furnaces of a Thermal Power Plant (TPP) of Candiota, State of Rio Grande do Sul, Brazil. The produced hot flue gas heats the water of the ECONOMIZER 01 (ECO 01) placed inside the exhausted duct. Distorted velocity profile at inlet of ECO 01 and high concentration of abrasive particles of flue gas cause drastic erosion. So intensive has been the abrasive action that some well-identified tubes end up collapsing. The unpredictable fail has caused many non-scheduled stops of the TPP. A study focused on the reduction this effect, was set up years ago. The paper shows part of this study end present results, obtained from the numerical simulation analysis of the flue gas flow. Some technical solutions are suggested to reduce the erosion of tubes providing that avoiding it showed be impossible.

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