Considering the high costs of the implementation and maintenance of gas distribution networks in urban areas, optimal design of such networks is vital. Today, urban gas networks are implemented within a tree structure. These networks receive gas from City Gate Stations (CGS) and deliver it to the consumers. This study presents a comprehensive model based on Mixed Integer Nonlinear Programming (...

The permeability of coal is a critical parameter in estimating the performance of coal reservoirs. Darcy’s law describes the flow pattern that the permeability has a linear relationship with the flow velocity. However, the stress induced deformation and damage can significantly influence the gas flow pattern and permeability of coal. Coals from Songzao coalfield in Chongqing, southwest China we...

three-phase (e.g., water, oil, and gas) flow in porous media, includcomplex than the corresponding two-phase curves. It is ing phase, global, and pseudo-global pressure-saturation formulathe complexity of these three-phase curves that complitions, are discussed in this paper. Comparisons of these differential cates the derivation of the global pressure-saturation form formulations are theoretic...

heat recuperation is often used to improve the overall cycle efficiency of gas turbines. however, generally in small- scale gas turbines, it has a negative effect on turbine inlet temperature, pressure ratio and pressure drops, and thus decreases the overall cycle efficiency. in this paper, a thermodynamic model is performed to evaluate recovered heat as a function of heat exchanger effectivene...

We carried out three-dimensional global resistive magnetohydrodynamic (MHD) simulations of the cooling instability in optically thin hot black hole accretion flows by assuming bremsstrahlung cooling. General relativistic effects are simulated by using the pseudo-Newtonian potential. Cooling instability grows when the density of the accretion disk becomes sufficiently large. We found that as the...

this study mainly focuses on enhancing the overall efficiency of gas transmission networks. the authors developed a model with detailed characteristics of compressor and pressure reduction stations. following this, they suggested three different systems with gas turbine including: organic rankine cycle (orc), air bottoming cycle (abc), and abc along with steam injection (si-abc). in addition, u...

Gas hydrates are a costly problem when they plug oil and gas pipelines. The best way to determine the HFT and pressure is to measure these conditions experimentally for every gas system. Since this is not practical in terms of time and money, correlations are the other alternative tools. There are a small number of correlations for specific gravity method to predict the hydrate formation. As th...

Gravity drainage is the main mechanism which controls the oil recovery from fractured reservoirs in both gas-cap drive and gas injection processes. The liquid bridge formed between two adjacent matrix blocks is responsible for capillary continuity phenomenon. The accurate determination of gas-liquid interface profile of liquid bridge is crucial to predict fracture capillary pressure precisely. ...

Nowadays one of the most important energy sources is natural gas. By depletion of oil reservoirs in the world, natural gas will emerge as the future energy source for human life. One of the major concerns of gas suppliers is being able to supply this source of energy the entire year. This concern intensifies during more consuming seasons of the year when the demand for natural gas increases, r...

determination of the starter torque-speed diagram is a major task in the design or selection of a proper gas turbine starter. in this paper, the maximum power of the mgt-40 gas turbine starter was calculated based on the dynamics of the rotor, start-up logic, and compressor map. in a recent research, the pressure ratio was assumed as a linear function of the rotor speed and the required starter...