scholarly journals Numerical Adaptation of Pipeline Network Models on Measurement Archive

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Vadim E. Seleznev
Keyword(s):  
Flow Resistance ◽  
Gas Transport ◽  
Measurement Data ◽  
Network Models ◽  
Parametric Identification ◽  
Transport Systems ◽  
Transport Parameters ◽  
Identification Problems ◽  
Pipeline Network ◽  
Adaptation Method

We propose an adaptation method for gas dynamic pipeline network models to enable credible representation of actual properties of real simulation objects. The presentation is illustrated by fitting equivalent pipeline section roughnesses used in the models to accommodate the influence of flow resistance on gas transport parameters. The method is based on the setting up and solution of a series of special parametric identification problems based on a limited set of field measurement data at local (in space) network points. This method can be used by specialists in mathematical modeling of gas transport systems to solve practical parametric identification problems.

scholarly journals Characterization of Gas Transport Properties of Compacted Solid Waste Materials

Environments ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 26
Author(s):  
Muhammad Rashid Iqbal ◽  
Hiniduma Liyanage Damith Nandika ◽  
Yugo Isobe ◽  
Ken Kawamoto
Keyword(s):  
Hydraulic Conductivity ◽  
Solid Waste ◽  
Gas Transport ◽  
Bottom Ash ◽  
Gas Diffusion ◽  
Saturated Hydraulic Conductivity ◽  
Dry Density ◽  
Transport Parameters ◽  
Functional Relations ◽  
Mixed Waste

Gas transport parameters such as gas diffusivity (Dp/D0), air permeability (ka), and their dependency on void space (air-filled porosity, ε) in a waste body govern convective air and gas diffusion at solid waste dumpsites and surface emission of various gases generated by microbial processes under aerobic and anaerobic decompositions. In this study, Dp/D0(ε) and ka(ε) were measured on dumping solid waste in Japan such as incinerated bottom ash and unburnable mixed waste as well as a buried waste sample (dumped for 20 years). Sieved samples with variable adjusted moistures were compacted by a standard proctor method and used for a series of laboratory tests for measuring compressibility, saturated hydraulic conductivity, and gas transport parameters. Results showed that incinerated bottom ash and unburnable mixed waste did not give the maximum dry density and optimum moisture content. Measured compressibility and saturated hydraulic conductivity of tested samples varied widely depending on the types of materials. Based on the previously proposed Dp/D0(ε) models, the diffusion-based tortuosity (T) was analyzed and unique power functional relations were found in T(ε) and could contribute to evaluating the gas diffusion process in the waste body compacted at different moisture conditions.

Kinetics and Mechanism of Gallium Arsenide Growth in Gas-Transport Systems

1986 ◽  
pp. 34-45
Author(s):  
L. G. Lavrentyeva ◽  
I. V. Ivonin ◽  
L. P. Porokhovnichenko
Keyword(s):  
Gallium Arsenide ◽  
Gas Transport ◽  
Kinetics And Mechanism ◽  
Transport Systems

scholarly journals Highly Permeable Matrimid®/PIM-EA(H2)-TB Blend Membrane for Gas Separation

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 46 ◽  
Author(s):  
Elisa Esposito ◽  
Irene Mazzei ◽  
Marcello Monteleone ◽  
Alessio Fuoco ◽  
Mariolino Carta ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Gas Transport ◽  
Gas Permeability ◽  
Time Lag ◽  
Gas Diffusion ◽  
Gas Permeation ◽  
Spectrometric Analysis ◽  
Competitive Sorption ◽  
Transport Parameters ◽  
Mixed Gas

The effect on the gas transport properties of Matrimid®5218 of blending with the polymer of intrinsic microporosity PIM-EA(H2)-TB was studied by pure and mixed gas permeation measurements. Membranes of the two neat polymers and their 50/50 wt % blend were prepared by solution casting from a dilute solution in dichloromethane. The pure gas permeability and diffusion coefficients of H2, He, O2, N2, CO2 and CH4 were determined by the time lag method in a traditional fixed volume gas permeation setup. Mixed gas permeability measurements with a 35/65 vol % CO2/CH4 mixture and a 15/85 vol % CO2/N2 mixture were performed on a novel variable volume setup with on-line mass spectrometric analysis of the permeate composition, with the unique feature that it is also able to determine the mixed gas diffusion coefficients. It was found that the permeability of Matrimid increased approximately 20-fold with the addition of 50 wt % PIM-EA(H2)-TB. Mixed gas permeation measurements showed a slightly stronger pressure dependence for selectivity of separation of the CO2/CH4 mixture as compared to the CO2/N2 mixture, particularly for both the blended membrane and the pure PIM. The mixed gas selectivity was slightly higher than for pure gases, and although N2 and CH4 diffusion coefficients strongly increase in the presence of CO2, their solubility is dramatically reduced as a result of competitive sorption. A full analysis is provided of the difference between the pure and mixed gas transport parameters of PIM-EA(H2)-TB, Matrimid®5218 and their 50:50 wt % blend, including unique mixed gas diffusion coefficients.

scholarly journals The Balance of Multi-phase Gathering and Transport Systems

2019 ◽  
Vol 290 ◽  
pp. 10002
Author(s):  
Cristian Nicolae Eparu ◽  
Sorin Neacsu ◽  
Renata Radulescu ◽  
Alina Petronela Prundurel
Keyword(s):  
Liquid State ◽  
Transport Systems ◽  
Gas Composition ◽  
Transport Parameters ◽  
Gaseous State ◽  
Natural Gases ◽  
Multi Phase

Natural gases are a mixture of hydrocarbons which are generally in a gaseous state. Due to the variation in transport parameters (pressure, temperature) and gas composition, there may be sectors where those appear in liquid state, the condensate. The paper presents a system for managing the quantities of fluids from a network in which the liquid state appears. Based on a simulator that includes flash computation, a physical balance of the transport or gathering network can be made.

scholarly journals Synthesis and gas transport parameters of membranes modified by star­shaped nanocrystalline palladium

2019 ◽  
Vol 486 (2) ◽  
pp. 163-167
Author(s):  
I. S. Petriev ◽  
S. N. Bolotin ◽  
V. Yu. Frolov ◽  
M. G. Baryshev
Keyword(s):  
Low Temperature ◽  
Flux Density ◽  
Hydrogen Transfer ◽  
Gas Transport ◽  
Transport Parameters ◽  
Alloy Films ◽  
Hydrogen Flux ◽  
Palladium Membranes

Methods have been developed to modify the surface of Pd-23%Ag alloy films in order to increase the rate of hydrogen transfer with appearance of palladium coatings of the “nanostar” and “nanopore” types. The gas transport parameters of the membranes which surface is activated using the developed methods were investigated. The modification of surface of Pd-Ag films synthesized by star-like palladium nanocrystallites allows achieving a hydrogen flux density of up to 0.75 mmol / (s × m2) - that is 1.7 times more than in case of modification modified by “nanopore” type coating of sufficiently thin palladium membranes (< 10 µm) under low temperature (<100 °C) and pressure (<0.6 MPa).

scholarly journals Forecasting rational working modes of long-operated gas-transport systems under conditions of their incomplete loading

2021 ◽  
Vol 4 (8(112)) ◽  
pp. 6-15
Author(s):  
Volodymyr Grudz ◽  
Yaroslav Grudz ◽  
Myroslav Iakymiv ◽  
Mykola Iakymiv ◽  
Pavlo Iagoda
Keyword(s):  
Mathematical Modeling ◽  
Energy Consumption ◽  
Transport System ◽  
Gas Transport ◽  
Pressure Fluctuations ◽  
Initial Pressure ◽  
High Amplitude ◽  
Nonstationary Process ◽  
Optimality Criteria ◽  
Transport Systems

Prolonged operation of the gas-transport system in conditions of partial loading involves frequent changes in the volume of gas transportation, which necessitates prompt forecasting of system operation. When forecasting the modes of operation of the gas transport system, the main criterion of optimality implies the maximum volume of gas pumping. After all, in this case, the largest profit of the gas-transport company is achieved under the condition of full provision of consumers with energy. In conditions of incomplete loading of the gas-transport system caused by a shortage of gas supply, optimality criteria change significantly. First, the equipment is operated in ranges far from nominal ones which leads to growth of energy consumption. Secondly, changes in performance cause high-amplitude pressure fluctuations at the outlet of compressor stations. Based on mathematical modeling of nonstationary processes, amplitude and frequency of pressure fluctuations at the outlet of compressor stations which can cause the pipeline overload have been established. To prevent this, it was proposed to reduce initial pressure relative to the maximum one. Calculated dependence was obtained which connects the amplitude of pressure fluctuations with the characteristics of the gas pipeline and the nonstationary process. Reduction in energy consumption for transportation is due to the shutdown of individual compressor stations (CS). Mathematical modeling has made it possible to establish regularities of reduction of productivity of the gas-transport system and duration of the nonstationary process depending on the location of the compressor station on the route. With an increase in the number of shutdown compression stations, the degree of productivity decrease and duration of nonstationarity reduces The established patterns and proposed solutions will improve the reliability of a gas-transport system by preventing pipeline overload and reduce the cost of gas transportation by selecting running numbers of shutdown stations with a known decrease in productivity.

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