A global thermodynamic measurement data reconciliation model considering boundary conditions and parameter correlations and its applications to natural gas compressors

Measurement ◽  
2021 ◽  
pp. 108972
Author(s):  
Dengji Zhou ◽  
Dawen Huang ◽  
Le Zhang ◽  
Jiarui Hao ◽  
Shixi Ma
Keyword(s):  
Natural Gas ◽  
Boundary Conditions ◽  
Measurement Data ◽  
Data Reconciliation ◽  
Thermodynamic Measurement

scholarly journals Data Analysis and Model Validation of Natural Gas Transmission Pipeline With Compressor Station

2019 ◽  
Author(s):  
David Cheng
Keyword(s):  
Performance Analysis ◽  
Natural Gas ◽  
Model Validation ◽  
Measurement Data ◽  
Real Life ◽  
Gas Pipeline ◽  
Physical Parameters ◽  
Pressure Drops ◽  
Natural Gas Transmission ◽  
Transmission Pipeline

Abstract Data from the DCS systems provides important information about the performance and transportation efficiency of a gas pipeline with compressor stations. The pipeline performance data provides correction factors for compressors as part of the operation optimization of natural gas transmission pipelines. This paper presents methods, procedure, and a real life example of model validation based performance analysis of gas pipeline. Statistic methods are demonstrated with real gas pipeline measurement data. The methods offer practical ways to validate the pipeline hydraulics model using the DCS data. The validated models are then used as performance analysis tools in evaluating the fundamental physical parameters and assessing the pipeline hydraulics conditions for potential issues influencing pressure drops in the pipeline such as corrosion (ID change), roughness changes, or BSW deposition.

scholarly journals Identifying occupant presence in a room based on machine learning techniques by measuring indoor air conditions

2020 ◽  
Vol 172 ◽  
pp. 22005
Author(s):  
Lucia Hanfstaengl ◽  
Michael Parzinger ◽  
Uli Spindler ◽  
Ulrich Wellisch ◽  
Markus Wirnsberger
Keyword(s):  
Machine Learning ◽  
Boundary Conditions ◽  
Heat Dissipation ◽  
Measurement Data ◽  
Test Sample ◽  
Supervised Machine Learning ◽  
Machine Learning Techniques ◽  
Automation System ◽  
Precise Control ◽  
Occupancy Detection

Knowing about the presence and number of people in a room can be of interest for precise control of heating, ventilation and air conditioning. To determine the number and presence of occupants cost-effectively, it is of interest to use already existing air condition sensors (temperature, humidity, CO2) of the building automation system. Different approaches and methods for determining presence have attracted attention in recent years. We propose an occupancy detection method based on a method of supervised machine learning. In an experiment, measurement data were recorded in a research apartment with controllable boundary conditions. The presence of people was simulated by artificial injection of water vapour, CO2 and heat dissipation. The variation of the number of artificial users, the duration of presence and the supply air volume flow of the ventilation resulted in a total of 720 combinations. By using artificial users, the boundary conditions were accurately defined, and different presence situations could be measured time-effectively. The data is evaluated with a method of supervised machine learning called random forest. The statistical model can determine precisely the number of people in over 93% of the cases in a disjoint test sample. The experiments took part in the Rosenheim Technical University of Applied Sciences laboratory.

Assessment of the Fatigue Life of a PWR Surge Line Including the Effect of Coolant Environment

2009 ◽  
Author(s):  
Gu¨nter Ko¨nig ◽  
Jaroslav Bartonicek ◽  
Horst Rothenho¨fer
Keyword(s):  
Boundary Conditions ◽  
Power Plants ◽  
Measurement Data ◽  
Real Life ◽  
Actual State ◽  
Optimized Design ◽  
Design Phase ◽  
Damage Mechanisms ◽  
Piping Systems ◽  
Surge Line

In Germany, the integrity concept is applied to important piping systems in most of the nuclear power plants. Regarding the framework of this concept, those damage mechanisms that cannot be controlled by analysis have to be excluded using appropriate measures. In most of the cases, these damage mechanisms are a result of local effects (like loads, medium, material characteristics) that cannot be determined exactly in advance and thus cannot be controlled by analysis, reliably. Examples are strain induced corrosion (LCF area) and corrosion fatigue (HCF area). For cases like these and given medium, suitable materials have to be chosen in combination with optimized design, appropriate manufacturing procedures (incl. welding), construction and operation. The loads and the water chemistry in operation have to be monitored and the effectiveness of the measures has to be verified, regularly, taking into account the actual state of knowledge. Regarding these boundary conditions the fatigue evaluations that have been performed until today seem to be sufficient, as experience shows with piping systems where this procedure has been applied. There are usually no significant failures (indication of failures); failures detected have been attributed to violation of the boundary conditions. With this background, there seems to be no need to change this procedure to safeguard the effect of environment. In this paper, the measures to guarantee integrity in design and operation state are discussed, first. Using the example of a surge line and the comprehensive monitoring results of this system the evaluation of fatigue usage and the assessment of the effect of coolant environment is discussed with reference to the ANL approach. Where the ANL approach is meant to be applied only in the design phase of a new reactor its relevance for the operation phase is cross-checked with real life measurement data. The conclusion summarizes where the effect of coolant environment has to be taken into account and gives advice how to find realistic transients for the design phase of new reactors.

Data Analysis and Model Validation of Natural Gas Transmission Pipeline With Compressor Station

2019 ◽  
Vol 4 (3) ◽  
Author(s):  
David Cheng
Keyword(s):  
Performance Analysis ◽  
Natural Gas ◽  
Model Validation ◽  
Measurement Data ◽  
Gas Pipeline ◽  
Pipeline System ◽  
Actual System ◽  
Natural Gas Transmission ◽  
Transmission Pipeline ◽  
Performance Analysis Tools

Abstract Data from the distributed control system (DCS) or supervisory control and data acquisition (SCADA) system provide useful information critical to the evaluation of the performance and transportation efficiency of a gas pipeline system with compressor stations. The pipeline performance data provide correction factors for compressors as part of the operation optimization of natural gas transmission pipelines. This paper presents methods, procedures, and an example of model validation-based performance analysis of a gas pipeline based on actual system operational data. An analysis approach based on statistical methods is demonstrated with actual DCS gas pipeline measurement data. These methods offer practical ways to validate the pipeline hydraulics model using the DCS data. The validated models are then used as performance analysis tools in assessing the pipeline hydraulics parameters that influence the pressure drop in the pipeline such as corrosion (inside diameter change), roughness changes, or basic sediment and water deposition.

Application of the Alternating Direction Explicit Procedure To Two-Dimensional Natural Gas Reservoirs

1966 ◽  
Vol 6 (02) ◽  
pp. 137-142 ◽  
Author(s):  
D. Quon ◽  
P.M. Dranchuk ◽  
S.R. Allada ◽  
P.K. Leung
Keyword(s):  
Natural Gas ◽  
Boundary Conditions ◽  
Computer Hardware ◽  
Management Tool ◽  
Two Dimensional ◽  
Gas Reservoirs ◽  
Fluid Saturation ◽  
Alternating Direction ◽  
Explicit Procedure ◽  
Natural Gas Reservoirs

Abstract The alternating direction explicit procedure (ADEP) makes use of the boundary conditions to reduce multi-dimensional problems to a series of one-dimensional problems. The method, previously applied to reservoirs containing only an undersaturated oil, bas now been extended to cover the case of natural gas reservoirs. Although this involves solving a non-linear partial differential equation, application of the procedure is straight- forward and no calculational problems were encountered. Introduction There has been a growing interest in formulating mathematical models of petroleum and natural gas reservoirs - models which permit the engineer to examine and evaluate the physical and economic consequences of various alternative production policies. The tremendous reduction in the cost of solving such models in recent years has made possible their use as an almost routine management tool. This reduction is the result not only of improved computer hardware but also of the development of more efficient mathematical techniques. The present paper is concerned with the application of a recently proposed numerical method (ADEP) to two-dimensional gas reservoirs. STATEMENT OF THE PROBLEM Given a two-dimensional Region R, bounded by a closed Curve C (Fig. 1) such that the behavior on Curve is known, the differential mass balance for each fluid phase in R, neglecting gravitational effects and assuming Darcy's law for fluid transport, can be written as: A typical and common set of boundary conditions is given by (1) / = 0 on Curve C where r is the direction normal to Curve C; (2) p is known throughout Region R at some time t; and (3) wf is known for all x, y and t. Physically, this represents the case where the reservoir is bounded by impermeable media, where the initial pressure throughout the reservoir at the beginning of gas production is known and where the production rate at each well is specified at all times. For single-phase reservoirs, the problem is to determine the pressure throughout Region R at all times; for multi-phase reservoirs, in addition to the pressure, the value of the fluid saturation is also required. Since analytical solutions to this equation for the general case are not available, we must resort to numerical integrating techniques, using finite-difference approximations. SPEJ P. 137ˆ

Continuous CH4 and  d13CH4 measurements in London demonstrate under-reported natural gas leakage

2021 ◽  
Author(s):  
Eric Saboya ◽  
Giulia Zazzeri ◽  
Heather Graven ◽  
Alistair J. Manning ◽  
Sylvia Englund Michel
Keyword(s):  
Natural Gas ◽  
Atmospheric Chemistry ◽  
Dispersion Model ◽  
Measurement Data ◽  
Atmospheric Methane ◽  
Bottom Up ◽  
Keeling Plot ◽  
Regional Emissions ◽  
The Uk ◽  
Gas Leaks

<p>Assessment of bottom-up greenhouse gas emissions estimates through independent methods is needed to demonstrate whether reported values are accurate or if bottom-up methodologies need to be refined. Previous studies of measurements of atmospheric methane (CH<sub>4</sub>) in London revealed that inventories substantially underestimated the amount of natural gas CH<sub>4</sub><sup> 1,2</sup>. We report atmospheric CH<sub>4</sub> concentrations and δ<sup>13</sup>CH<sub>4</sub> measurements from Imperial College London since early 2018 using a Picarro G2201-i analyser. Measurements from Sept. 2019-Oct. 2020 were compared to the values simulated using the dispersion model NAME coupled with the UK national atmospheric emissions inventory, NAEI, and the global inventory, EDGAR, for emissions outside the UK. Simulations of CH<sub>4</sub> concentration and δ<sup>13</sup>CH<sub>4</sub> values were generated using nested NAME back-trajectories with horizontal spatial resolutions of 2 km, 10 km and 30 km. Observed concentrations were underestimated in the simulations by 22 % for all data, and by 16 % when using only 13:00-17:00 data. There was no correlation between the measured and simulated δ<sup>13</sup>CH<sub>4</sub> values. On average, simulated natural gas mole fractions accounted for 28 % of the CH<sub>4 </sub>added by regional emissions, and simulated water sector mole fractions accounted for 32 % of the CH<sub>4</sub>added by regional emissions. To estimate the isotopic source signatures for individual pollution events, an algorithm was created for automatically analysing measurement data by using the Keeling plot approach. Nearly 70 % of isotopic source values were higher than -50 ‰, suggesting the primary CH<sub>4 </sub>sources in London are natural gas leaks. The model-data comparison of δ<sup>13</sup>CH<sub>4 </sub>and Keeling plot results both indicate that emissions due to natural gas leaks in London are being underestimated in the UK NAEI and EDGAR.</p><p> </p><p><sup>1 </sup>Helfter, C. et al. (2016), Atmospheric Chemistry and Physics, 16(16), pp. 10543-10557</p><p><sup>2</sup> Zazzeri, G. et al. (2017), Scientific Reports, 7(1), pp. 1-13</p>

A Study on Energetic and Hydraulic Interaction of Combined Journal and Thrust Bearings

2015 ◽  
Author(s):  
Thomas Hagemann ◽  
Hardwig Blumenthal ◽  
Christian Kraft ◽  
Hubert Schwarze
Keyword(s):  
Boundary Conditions ◽  
High Speed ◽  
Thrust Bearing ◽  
Journal Bearing ◽  
Measurement Data ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Minor Importance ◽  
Thrust Bearings ◽  
Side Flow

A theoretical algorithm for the analysis of bidirectional interaction of combined journal and thrust bearings is presented. While many theoretical and experimental investigations on the operating behavior of single journal and thrust bearings can be found only few results for combined bearings are available. However, combined bearings interact by exchanging lubricant and heat which can affect significant changes of boundary conditions compared to a single bearing application. Therefore, a novel procedure is developed to combine two separate codes for journal and thrust bearings in order to iteratively determine the coupling boundary conditions due to the special design of the entire bearing unit. The degree of interaction strongly depends on the type of lubrication. In a first step predictions are verified by measurement data for a combined bearing with a fixed-pad offset-halves journal bearing and a directed lubricated tilting-pad thrust bearing. Experiments were conducted on a high speed test rig up to sliding speeds of 107 m/s at the mean radius of the thrust bearing. As expected the interaction of the two oil films is comparably low in the investigated speed and load range for this bearing design because of the active lubrication of both bearings and the low hydraulic resistance of the thrust bearing. In order to theoretically investigate interaction of thrust and journal bearings in more details a combined bearing with fixed-pad thrust parts lubricated exclusively by the side flow of the journal bearing is studied. A variation of modeling level, pocket design of the journal part, thrust load and rotating frequency provides the following results: (i) hydraulic and energetic interaction have to be modelled in details, (ii) the axial flow resistance of the pockets strongly influences flow rates and the pressure level at the interfaces (iii) the level of interface pressure rises with increasing thrust loads and decreasing rotor speed, (iv) the axial bearing clearance is rather of minor importance for the investigated bearing. Finally, improvements in order to predict operating conditions more precisely are comprehensively discussed.

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