Assessment of the Effectiveness of Gas Path Diagnostic Schemes

2004 ◽  
Vol 128 (1) ◽  
pp. 57-63 ◽  
Author(s):  
K. Mathioudakis ◽  
Ph. Kamboukos
Keyword(s):  
Gas Turbines ◽  
Individual Component ◽  
Uncertainty Propagation ◽  
Data Retrieval ◽  
Operating Conditions ◽  
Small Deviations ◽  
Component Identification ◽  
Operating Points ◽  
Selection Of

A variety of methods can be used for the diagnosis of faults in gas path components of gas turbines. Problems that are common for diagnostic method implementation are the choice of measured quantities, choice of health parameters, and choice of operating conditions for data retrieval. The present paper introduces some general principles for evaluation of the effectiveness of different diagnostic schemes. They encompass criteria proposed in past publications, while they offer additional possibilities for assessment of diagnostic effectiveness in various situations. The method is based on the evaluation of the behavior of linear systems, which are a good approximation of the nonlinear ones for small deviations and employs the concept of system condition number to formulate criteria. The determination of limits for this number for establishing system condition criteria and quantification of observability is examined, on the basis of uncertainty propagation. Sample problems evaluated are: maximizing effectiveness of individual component identification from a multiplicity of available measurements, selection of individual operating points for multipoint applications.

Assessment of the Effectiveness of Gas Path Diagnostic Schemes

2004 ◽  
Author(s):  
K. Mathioudakis ◽  
Ph. Kamboukos
Keyword(s):  
Gas Turbines ◽  
Individual Component ◽  
Uncertainty Propagation ◽  
Data Retrieval ◽  
Operating Conditions ◽  
Small Deviations ◽  
Component Identification ◽  
Operating Points ◽  
Selection Of

A variety of methods can be used for the diagnosis of faults in gas path components of gas turbines. Problems that are common for diagnostic method implementation are the choice of measured quantities, choice of health parameters and choice of operating conditions for data retrieval. The present paper introduces some general principles for evaluation of the effectiveness of different diagnostic schemes. They encompass criteria proposed in past publications, while they offer additional possibilities for assessment of diagnostic effectiveness in various situations. The method is based on the evaluation of the behavior of linear systems, which are a good approximation of the non-linear ones for small deviations and employs the concept of system condition number to formulate criteria. The determination of limits for this number for establishing system condition criteria and quantification of observability is examined, on the basis of uncertainty propagation. Sample problems evaluated are: maximizing effectiveness of individual component identification from a multiplicity of available measurements, selection of individual operating points for multi-point applications.

Parametric Optimization of Structures Under Combined Base Motion Direct Forces and Static Loading

1998 ◽  
Vol 124 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Izhak Bucher
Keyword(s):  
Degrees Of Freedom ◽  
Structural Parameters ◽  
Operating Conditions ◽  
Design Parameters ◽  
Power Spectral ◽  
Loading Patterns ◽  
The Cost ◽  
Selection Of ◽  
Eigenvectors And Eigenvalues

This paper deals with the optimization of vibrating structures as a mean for minimizing unwanted vibration. Presented in this work is a method for automatic determination of a set of preselected design parameters affecting the geometrical layout or shape of the structure. The parameters are selected to minimize the dynamic response to external forcing or base motion. The presented method adjusts the structural parameters by solving an optimization problem in which the constraints are dictated by engineering considerations. Several constraints are defined so that the static deflection, the stress levels and the total weight of the structure are kept within bounds. The dynamic loading acting upon the structure is described in this work by its power spectral density, with this representation the structure can be tailored to specific operating conditions. The uncertain nature of the excitation is overcome by combining all possible spectra into one PSD encompassing all possible loading patterns. An important feature of the presented method is its numerical efficiency. This feature is essential for any reasonably sized problem as such problems are usually described by thousands of degrees of freedom arising from a finite-element idealization of the structure. In this paper, efficient, closed form expressions, for the cost function and its gradients are derived. Those are computed with a partial set of eigenvectors and eigenvalues thus increasing the efficiency further. Several numerical examples are presented where both shape optimization and the selection of discrete components are illustrated.

Determination of qualitative indicators of the work of the wide sprinkling machine

2020 ◽  
Vol 0 (5) ◽  
pp. 25-28
Author(s):  
Vladimir Slabunov ◽  
Aleksandra Slabunova ◽  
Andrey Kupriyanov
Keyword(s):  
Wind Speed ◽  
Federal State ◽  
Small Deviations ◽  
Irrigation Uniformity ◽  
Actual Flow Rate ◽  
Actual Flow ◽  
Rain Drops ◽  
Water Pipeline ◽  
Selection Of

The aim of the research is to select the diameters of the nozzles of the deflector nozzles and to determine the quality indicators of the operation of a new wide-grip sprinkler of circular action, developed at the Federal State Budgetary Scientific Institution «RosNIIPM». The selection of the diameters of the nozzles of the deflector nozzles was carried out from the conditions of passing three different flows through the DM water pipeline: 15, 30 and 60 l/s. The scheme of their arrangement – rain-forming devices have different flow rates and diameters of nozzles at the same distance between them along the DM water-conducting pipeline. The analysis of the results obtained showed small deviations in the actual flow rate of the deflector nozzles through the water pipeline (cf. deflector nozzles with calculated nozzle diameters. Investigations of irrigation uniformity were carried out, as a result of which the following results were obtained: effective irrigation coefficient – 0.67–0.78; the coefficient of insufficient irrigation is 0.10–0.12, the coefficient of excessive irrigation is 0.12–0.15. At the same time, a decrease in the uniformity of irrigation is associated with an increase in wind speed and thereby an increase in the drift of artificial rain drops, the worst condition for the use of a WDM is a wind speed of more than 5 m/s, and therefore it is recommended to use this DM in the morning and evening, characterized by a more reduced wind load.

Replacement of MEG with KHI for Hydrate Control in Subsea Flowline Offshore Myanmar

2021 ◽  
Author(s):  
Jonghyun Kim ◽  
Paolo Scalea ◽  
Chulhwan Hwang ◽  
Jeongmoon Kim
Keyword(s):  
Selection Process ◽  
Field Tests ◽  
Equilibrium Temperature ◽  
Field Application ◽  
Operating Conditions ◽  
Field Conditions ◽  
Gas Industry ◽  
Promising Alternative ◽  
Selection Of

Abstract Objectives/Scope This paper describes the successful replacement of Mono Ethylene Glycol (MEG) by Kinetic Hydrate Inhibitor (KHI) to guarantee flow assurance in the Shwe field subsea production system, offshore Myanmar. It covers the initial difficulties experienced with MEG, specific field conditions, the comprehensive KHI selection process and testing up to field application and operation. Methods, Procedures, Process MEG used for hydrate inhibition in the field's subsea flowline was originally regenerated in the topside facility, however contamination of the MEG with salts from formation water was causing process upsets. The option of installing a reclamation package presented many challenges and, after review of field conditions, the application of a KHI was considered as a promising alternative to MEG. With the engagement of specialist chemical suppliers a broad and challenging series of laboratory, as well as field tests, was carried out to select a suitable product. Finally a dedicated permanent injection skid was installed to guarantee stable KHI delivery and production. Results, Observations, Conclusions The difficulties caused by salt contamination of the MEG system, combined with the intricate field logistics at the remote site offshore Myanmar, entailed a speedy solution. This combined with suitable operating parameters of the field; i.e. low water content, high wellhead flowing temperatures, subcooling within known KHI operating range, ensured KHI was an economical solution. Nevertheless from desktop study to successful field application a series hurdles had to be crossed, including performance and compatibility tests, simulating all the expected Shwe Offshore Platform (SHP) operating conditions: Determination of Hydrate Equilibrium Temperature (HET); Induction Time Autoclave test for the required residence time in the presence of Corrosion Inhibitor (CI); Hot Injection ests at wellhead operating temperature; Thermal stability tests for topsides and condensate disposal system; Umbilical material compatibility tests; Compatibility of KHI with incumbent products (MEG and CI). Testing of a range of products, carried out by specialist chemical supplier, resulted in the selection of a qualified product, followed by a successful field application testing programme. Seven years after its introduction, KHI has helped achieve optimum field uptime and reduced operational costs as well as eased logistics constraints. Novel/Additive Information KHI is not new to the Oil & Gas industry, however information on its selection and application is not widely available. This paper sheds light on the steps to be considered when evaluating KHI as a suitable hydrate inhibitor, as well as the detailed laboratory tests for proper selection of a product. The intent is to help operators who are facing challenges with hydrate inhibition and could revert to KHI as an alternative.

scholarly journals Evaluación de irreversibilidades en un sistema de refrigeración por absorción amoniaco-agua empleando tres modelos matemáticos diferentes para calcular las propiedades termodinámicas

2018 ◽  
Vol 27 (47) ◽  
Author(s):  
Iván Vera-Romero ◽  
Christopher Lionel Heard-Wade
Keyword(s):  
Individual Component ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Second Law ◽  
Base Case ◽  
Water Mixture ◽  
Absorption Refrigeration ◽  
Second Law Analysis ◽  
Exergy Analyses

Second Law or Exergy Analyses of Absorption Refrigeration Systems (ARS) are very important for optimisations based on available work; these analyses are derived from the operating conditions and property calculations. There are several methods available for calculating the thermodynamic properties used in modelling these systems. A thermodynamic study on an ARS with the ammonia-water mixture (base case) was carried out with the objective of analysing the sensitivity of the overall and individual component irreversibility to the thermodynamic property. To this end, three existing methods were used: (M1), a model proposed by Ibrahim and Klein (1993) and used in the Engineering Equation Solver (EES) commercial software; (M2), a model proposed by Tillner-Roth and Friend (1998) and embodied in REFPROP v.8.0 developed by the National Institute of Standards and Technology (NIST); and (M3), a method proposed by Xu and Goswami (1999) that was programmed for this analysis. The obtained differences in the properties and the first law performance of the ARS are insignificant in the determination of the coefficient of performance (COP) (base case: 0.595, M1: 0.596, M2: 0.594, M3: 0.599). For the second law analysis, the overall irreversibility was the same (123.339kW) despite the irreversibilities per component had important differences: the solution heat exchanger (M1: 5.783kW, M2: 6.122kW, M3: 8.701kW), the desorber (generator) (M1: 51.302kW, M2: 45.713kW, M3: 49.098kW) and the rectifier (M1: 0.766kW, M2: 3.565kW, M3: 0.427kW). The components that destroy exergy the most are the desorber, the absorber and the condenser.

scholarly journals Analysis of the exhaust emissions from hybrid vehicle during RDE test

2019 ◽  
Vol 294 ◽  
pp. 02002
Author(s):  
Andrzej Ziolkowski ◽  
Pawel Daszkiewicz ◽  
Lukasz Rymaniak ◽  
Paweł Fuc ◽  
Pawel Ukleja
Keyword(s):  
Exhaust Emissions ◽  
Operating Conditions ◽  
Drive System ◽  
Heavy Vehicles ◽  
Hybrid Drive ◽  
Emission Norm ◽  
Urban Rural ◽  
Test Route ◽  
Selection Of

The introduction of the Euro 6c emission norm in 2017 resulted in a change of the type approval procedures. The most important of these was the replacement of the NEDC test with WLTC test with different procedures. In addition, the research was extended to include emission tests in real operating conditions (RDE). Such tests are enforced for heavy vehicles since 2014. PEMS apparatus was used for the measurements, which has been used by many research and development centers to carry out exhaust emissions measurements long before the applicable procedures were introduced. The article presents the methodology of conducting RDE measurements in accordance with the requirements defined by the Euro 6c norm. The focus in this case was primarily on the selection of the test route in the Poznań agglomeration. After determining its course, RDE measurements were made for a vehicle with a hybrid drive. The test route parameters have complied with the applicable requirements. All requirements were met and it was possible to analyze the exhaust emissions. The main focus being the determination of exhaust emissions from the entire test and in accordance with the EMROAD method. The CF (Comformity Factor) coefficients were also determined for both methods and compared with the applicable legal values. An analysis of the hybrid drive system operation was carried out, defining the degree of hybridization, which is the portion of the vehicle travel using only the electric motor of the drive system throughout the whole test. All analyzes were carried out in individual sections of the test: urban, rural and motorway.

scholarly journals FORMALIZATION OF THE PROBLEM OF SELECTION OF AUTOMATED SYSTEM

2018 ◽  
pp. 16-20
Author(s):  
A. V. Petukhov
Keyword(s):  
Economic Effect ◽  
Operating Conditions ◽  
Automated System ◽  
Qualitative Assessment ◽  
Automated Systems ◽  
Customer Requirements ◽  
Qualitative And Quantitative ◽  
Complete Restoration ◽  
Selection Of

The results of many years of research in the field of formalizing the task of selecting automated systems for various areas of design and office activities are given. The purpose of the study is the development of methods for qualitative and quantitative evaluation when choosing an automated system, taking into accounts the operating conditions and customer requirements. Qualitative assessment is based on the theory of choice and decision making, which examines the mathematical models of this type of activity. In view of the fact that in the problem under consideration, many alternatives, which are automated systems, are known, it can be related to the choice problem. The peculiarity of this approach is that it does not require a complete restoration of the principle of optimality, but allows us to confine ourselves to information sufficient to identify the optimal variant. The quantitative assessment is based on the determination of the projected annual economic effect from the introduction of an automated system. The described technique can be used by enterprises and organizations in the evaluation of automated systems at the stage preceding the tender for their purchase.

scholarly journals Acidic Gases Separation from Gas Mixtures on the SILMs Providing the Facilitated and Solution-Diffusion Transport Mechanisms

2018 ◽  
Author(s):  
Alsu I. Akhmetshina ◽  
Alla Mochalova ◽  
Maxim M. Trubyanov ◽  
Artem A. Atlaskin ◽  
Nail R. Yanbikov ◽  
...  
Keyword(s):  
Operating Conditions ◽  
Separation Performance ◽  
Factors Affecting ◽  
Acidic Gases ◽  
Membrane Performance ◽  
Ideal Selectivity ◽  
Counter Ions ◽  
Supported Ionic Liquid Membranes ◽  
Selection Of

Nowadays, the imidazolium-based ionic liquids containing acetate counter-ions are attracting much attention as both highly selective absorbents of the acidic gases and CO2 carriers in the supported ionic liquid membranes. In this regard, the investigation of the gas transport properties of such membranes may be appropriate for better understanding of various factors affecting the separation performance and the selection of the optimal operating conditions. In this work, we have tested CH4, CO2 and H2S permeability across the SILM impregnated by 1-butyl-3-methylimidazolium acetate (bmim[ace]) with the following determination of the ideal selectivity in order to compare the facilitated transport membrane performance with the SILM that dissolves acidic gases physically, namely, containing 1-butyl-3-methylimidazolium tetrafluoroborate (bmim[BF4]). Both SILMs have showed modest individual gases permeability and ideal selectivity of CO2/CH4 and H2S/CH4 separation that achieves values up to 15 and 32, respectively. The effect of the feed gas mixture composition on the permeability of acidic gases and permeselectivity of the gas pair was investigated. It turned out that the permeation behavior for the bmim[ace]-based SILM toward the binary CO2/CH4, H2S/CH4 and ternary CO2/H2S/CH4 mixtures was featured with high acidic gases selectivity due to the relatively low methane penetration through the liquid phase saturated by acidic gases.

Experimental and CFD Based Determination of Flutter Limits in Supersonic Space Turbines

2008 ◽  
Author(s):  
Pieter J. Groth ◽  
Hans E. Ma˚rtensson ◽  
Niklas Edin
Keyword(s):  
Operating Conditions ◽  
Total System ◽  
Nodal Diameter ◽  
Aerodynamic Damping ◽  
Velocity Flow ◽  
Flutter Boundary ◽  
Predicted Values ◽  
Operating Points ◽  
Amplitude Growth

Turbines operating at high pressure in high velocity flow are susceptible to flutter. As reduced frequencies become sufficiently low, negative aerodynamic damping will be found in some modes. Ensuring that the total system damping is positive over the entire turbine operating envelope for all modes is of utmost importance in any design since flutter in a turbine often causes blade failures. This is in contrast to the normal engineering approach, which is to require a positive aerodynamic damping. A unique test campaign with a 1.5 stage supersonic space turbine has been performed. The turbine was operated at simulated running conditions over a large operating envelope in order to map out flutter limits. During the test, flutter was intentionally triggered at seven different operating conditions. Unique data have been obtained during the test that supports validation of design tools and enables better understanding of flutter in this type of turbine. Based on the data the flutter boundary for the turbine could be established. Using CFD tools flutter was predicted at all operating points where the flutter limit was crossed. Both in predictions and as evidenced in test the 2 nodal diameter backward traveling mode was the most unstable. In addition to this predicted values of aerodynamic damping at flutter agreed well with damping estimated from measured amplitude growth.

Selective synthesis of (3-ferrocenylprop-2-en-1-yl)triphenylphosphonium iodide: crystal structure determination of two polymorphs

2017 ◽  
Vol 73 (5) ◽  
pp. 376-381
Author(s):  
Rafika Bouchene ◽  
Jean Claude Daran ◽  
Hocine Merazig ◽  
Eric Manoury ◽  
Sofiane Bouacida
Keyword(s):  
Reaction Medium ◽  
Operating Conditions ◽  
Yield Optimization ◽  
Space Group ◽  
Π Interactions ◽  
Monoclinic Form ◽  
Phosphorus Containing ◽  
Polymorphic Forms ◽  
Selection Of

This work is part of a project studying the reactivity of a new ferrocenyl allylammonium salt, [3-(trimethylazaniumyl)prop-1-en-1-yl]ferrocene iodide, (1+)·I−, with different nucleophiles. With nitrogen-based nucleophiles, different ferrocenyl allylamine isomers have been synthesized successfully in good yield. Optimization of the basicity of the reaction medium has allowed selection of the best operating conditions to obtain the targeted isomer. In a similar way and in order to introduce phosphorus-containing functional groups, the reaction of ammonium salt (1+)·I− with a phosphorus nucleophile, namely triphenylphosphane, was attempted. It was then possible to isolate single crystals of (3-ferrocenylprop-2-en-1-yl)triphenylphosphonium iodide, [Fe(C5H5)(C26H23P)]I, which is shown to crystallize in two concomitant polymorphic forms, viz. a triclinic form, (I), in the space group P\overline{1}, and a monoclinic form, (II), in the space group P21/c. In the inter-ion packing of polymorph (I), the cations form bilayer ribbons via C—H...π and π–π stacking interactions. In polymorph (II), where π–π interactions do not occur, adjacent molecules are joined by C—H...π interactions into a one-dimensional helical arrangement along the b axis.

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