scholarly journals Method for Calculating Transients in a Gas Pipeline

2021 ◽  
Vol 64 (5) ◽  
pp. 426-458
Author(s):  
A. S. Fikov
Keyword(s):  
Boundary Conditions ◽  
Analytical Model ◽  
Flow Rate ◽  
Gas Flow ◽  
Initial Moment ◽  
Gas Pipelines ◽  
Gas Flow Rate ◽  
Labor Costs ◽  
Duhamel Integral ◽  
Complex Boundary

Abstaract. An analytical solution of a system of partial differential equations describing the unsteady isothermal flow of real gases in gas pipelines is considered. Such a problem arises when studying the regularity of alterations in the instantaneous values of pressure and gas flow in main gas pipelines, for example, during startups and shutdowns of large gas consumers. Meanwhile, transients are not necessarily of a pronounced oscillatory nature, despite the fact that they are described by periodic functions. In the course of the research, the task was set to obtain a mathematical model of the process taking into account the inertial term of the equation of motion, the neglect of which is possible only if the friction losses are exceeded by 3.5–4 times over the shock pressure. An important feature of the solution that have been found is its universality, which makes it possible to significantly reduce labor costs when using it to find partial solutions to practical problems that differ in boundary conditions. The boundary conditions of the first kind are given as an arbitrary function of both the gas flow rate and its pressure. The solution is based on the widely used method of separation of Fourier variables. In order to simplify the calculations, the original differential equation is transformed in such a way that the boundary conditions acquire the property of homogeneity. It has been determined that the requirements that the boundary conditions are equal to zero at the initial moment of time introduced into the solution make it possible to obtain a concise record of the obtained analytical model, but do not limit the area of the use of the model with a surge change in the gas flow rate or pressure. The obtained analytical model of unsteady gas flow makes it possible, without using the Duhamel integral, to find analytical solutions under more complex boundary conditions than the flow rate jump. At the same time, the solutions found completely coincide with the solutions based on the Duhamel integral, but in the course of the solution that we have found it is possible to avoid integration, which has a positive effect on the applicability of this approach in the practice of engineering calculations.

METHODOLOGICAL ASPECT OF ASSESSING RELIABILITY OF MEDIUM PRESSURE GAS PIPELINES

2021 ◽  
pp. 97-107
Author(s):  
A.I. Pashentsev ◽  
A.A. Garmider
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Methodological Approach ◽  
Gas Pipeline ◽  
Methodological Aspect ◽  
Gas Pipelines ◽  
Gas Flow Rate ◽  
Medium Pressure ◽  
Reliability Calculation

The author’s vision of the methodological aspect of assessing the reliability of medium pressure gas pipelines is presented. Analysis of existing methods for assessing the reliability of gas pipelines with the identification of positive and negative features was carried out, a methodological approach to assessing the reliability of medium pressure gas pipelines by gas flow rate and pressure was developed and tested, and a scale for identifying the results of reliability calculation was developed. The test conducted on the example of a really working gas pipeline with a test for reliability showed its promise.

SCIENTIFIC AND ENGINEERING PRINCIPLES OF EFFICIENT FUEL USE AND ENVIRONMENTALLY FRIENDLY GAS COMBUSTION IN STOVE PLATES. PART 1. MODERN STATE-OF-THE-ART AND DIRECTIONS FOR IMPROVEMENT THE GAS BURNING IN DOMESTIC GAS COOKERS

2017 ◽  
pp. 3-18 ◽  
Author(s):  
B.S. Soroka ◽  
V.V. Horupa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Gas Flow ◽  
Renewable Energy Sources ◽  
Combustion Process ◽  
Orifice Diameter ◽  
Firing Process ◽  
Gas Flow Rate ◽  
Gas Combustion ◽  
Gas Stoves

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.

On the Influence of Fluctuating Flow Rate Upon the Performance and Behaviour of Isothermal Reacting Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluidized Bed Reactor ◽  
Computational Techniques ◽  
Continuous Stirred Tank Reactor ◽  
Gas Flow Rate ◽  
Solid Reaction ◽  
Continuous Stirred Tank ◽  
And Performance ◽  
Reacting Systems

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.

scholarly journals Investigation on influences of loose gas on gas-solid flows in a circulating fluidized bed (CFB) reactor using full-loop numerical simulation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Pengju Huo ◽  
Xiaohong Li ◽  
Yang Liu ◽  
Haiying Qi
Keyword(s):  
Numerical Simulation ◽  
Flow Rate ◽  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Separation Efficiency ◽  
Circulation Rate ◽  
Solid Mass ◽  
Gas Flow Rate ◽  
Gas Leakage ◽  
Mass Circulation

AbstractThe influences of loose gas on gas-solid flows in a large-scale circulating fluidized bed (CFB) gasification reactor were investigated using full-loop numerical simulation. The two-fluid model was coupled with the QC-energy minimization in multi-scale theory (EMMS) gas-solid drag model to simulate the fluidization in the CFB reactor. Effects of the loose gas flow rate, Q, on the solid mass circulation rate and the cyclone separation efficiency were analyzed. The study found different effects depending on Q: First, the particles in the loop seal and the standpipe tended to become more densely packed with decreasing loose gas flow rate, leading to the reduction in the overall circulation rate. The minimum Q that can affect the solid mass circulation rate is about 2.5% of the fluidized gas flow rate. Second, the sealing gas capability of the particles is enhanced as the loose gas flow rate decreases, which reduces the gas leakage into the cyclones and improves their separation efficiency. The best loose gas flow rates are equal to 2.5% of the fluidized gas flow rate at the various supply positions. In addition, the cyclone separation efficiency is correlated with the gas leakage to predict the separation efficiency during industrial operation.

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