Complete Similarity Mathematical Models on Laminar Forced Film Condensation of Vapour–Gas Mixture

2010 ◽  
pp. 241-272
Author(s):  
Deyi Shang
Keyword(s):  
Mathematical Models ◽  
Film Condensation ◽  
Gas Mixture

Chemical Sensor Array Modeling: Application to Resistive Based Chemo Sensors

2014 ◽  
Vol 605 ◽  
pp. 15-18
Author(s):  
Abdelaziz Abbas ◽  
Ahcene Bouabdallah
Keyword(s):  
Mathematical Models ◽  
Differential Form ◽  
Sensor Array ◽  
Chemical Sensor ◽  
Sensor Arrays ◽  
Gas Mixture ◽  
State Equations ◽  
Dynamical Equilibrium ◽  
Chemical Sensor Array ◽  
Intensive Quantities

The aim of paper is to develop analytical mathematical models that describe the thermo dynamical equilibrium of resistive chemical sensor arrays /mixture of vapors multi-system. By using the Gibbs Duhem formalism, state equations in differential form, that the variations of intensive quantities (e.g. sensors partial sensitivity) as function of the gas mixture components concentrations and sensor array parameters describe, have been developed. Moreover, the responses of the sensor arrays as function of gas mixture components concentrations were modeled.

scholarly journals Problems of analysis, optimization and control in the separation of gas mixtures

2018 ◽  
Vol 80 (2) ◽  
pp. 93-100
Author(s):  
E. I. Akulinin ◽  
O. O. Golubyatnikov ◽  
D. S. Dvoretskii ◽  
S. I. Dvoretskii
Keyword(s):  
Differential Equations ◽  
Mathematical Models ◽  
Relative Error ◽  
Synthesis Gas ◽  
Method Of Lines ◽  
Air Separation ◽  
Gas Mixture ◽  
Wide Range ◽  
Adsorption Desorption ◽  
Kinetics Of

Mathematical models of dynamics of pressure swing adsorption processes for the separation of synthesis gas (into hydrogen, carbon dioxide and carbon monoxide) and air (into oxygen, nitrogen and argon) have been developed. The models allow calculating the profiles of component concentrations and temperature of gas and solid phases, pressure and velocity of gas mixture along the height of adsorbent in relation to time. The models include the following equations: 1) processes of mass and heat transfer during the adsorption (desorption) of a sorptive (H2, CO2, COandO2, N2, Ar) by granulated zeolite adsorbents 5Aand13Х; 2) kinetics of compound diffusion transport of adsorbate and Langmuir-Freundlich isotherm (for the synthesis gas separation), kinetics of external diffusion and Dubinin-Radushkevich isotherm (for the air separation); 3) the Ergun equation for the calculation of pressure and velocity of gas mixture in adsorbent.The system of partial differential equations was solved by method of lines. The system of ordinary differential equations was solved by the fourth-order Runge-Kutta method with automatic step selection.To analyze the accuracy of mathematical models of the adsorption separation of synthesis-gas for recovery hydrogen, the relative error of the mismatch between the calculated values for the model and the experimental values of the concentration of the product (hydrogen, oxygen) in the 'steady state' (after 15-30 operating cycles of the PSA) was calculated. The maximum value of the relative error did not exceed 11.5%.Numerical studies were carried out in a wide range of changes in the time of the cycle "adsorption-desorption" and the pressure at the stage of adsorption to determine the effect of changes in temperature, composition and pressure of the initial gas mixture on the purity, recovery and temperature of production hydrogen and oxygen, as well as the relationship of the PSA unit capacity with the purity of the resulting product (hydrogen, oxygen). The problem of adaptive optimization of the process of adsorption separation of a gas mixture and obtaining hydrogen and oxygen with a maximum concentration was formulated and solved.The algorithmic and software of the automated adaptive control system was developed.

scholarly journals Числове та експериментальне дослідження наповнення резервуару компонентом газової суміші

2021 ◽  
pp. 63-72
Author(s):  
Ольга Володимирівна Шипуль ◽  
Сергій Олександрович Заклінський ◽  
Володимир Вікторович Комбаров ◽  
Олексій Анатолійович Павленко ◽  
Вадим Олегович Гарін
Keyword(s):  
Mathematical Models ◽  
Numerical Models ◽  
Control Point ◽  
Calculated Data ◽  
Full Scale ◽  
Mixture Component ◽  
Gas Mixture ◽  
Gas Temperature ◽  
Gas Dynamic ◽  
Simulation Results

The subject of the research is mathematical models of a gas-dynamic non-stationary process of filling a vessel with a component of a gas mixture. The aim of the study is the scientific and experimental substantiation of the choice of a model of filling a vessel with a component of a gas mixture with a given accuracy. The objectives of the study are to conduct full-scale experiments on filling the vessel with gas for further verification of the gas mixture generation control system, as well as in the development of adequate mathematical models of gas-dynamic flow, the analysis of simulation results, and the use of verified results in the system of automated generation of a gas mixture of a given accuracy by assessing the mass of its components depending on the filling parameters. The tasks are solved by studying the results of numerical modeling of the process and full-scale experiments. The following results are obtained. A series of full-scale experiments on filling a vessel with high-frequency monitoring of the pressure and temperature of the gas being filled was carried out. Significant factors were analyzed. The use of SAS SST turbulence models was substantiated. Models of the gas-dynamic unsteady process of filling the vessel with a component of the gas mixture for various values of the mass flow rate had been built. All the simulations were carried out using the ANSYS CFX software package. The influence of considering a heat exchange with the vessel walls on the studied parameters of the mixture is determined, namely: pressure, gas temperature averaged over the volume, gas temperature in a control point, mass of the component of a gas mixture. It was found that the deviation of the calculated data when using a model with an adiabatic condition on the wall compared to a model with a constant temperature regime is: for pressure – no more than 5 %, for averaged temperature – 6 %, for the temperature at the monitor point – 9 %, for mass – 1.5 %. The discrepancy between the simulation results and the full-scale experiment does not exceed 12 % in pressure and temperature at the monitor point, as well as 4 % in the mass of the component. By the experimentally determined accuracy parameter of the gas mixture (the mass of the mixture component in particular), the numerical models had been corrected to provide the mass value error of no more than 0.5 %.

scholarly journals A Two-Model Complex for Research into the Process of Adsorption Obtaining Hydrogen from Natural Gas Steam Reforming Products

2021 ◽  
Vol 27 (4) ◽  
pp. 528-535
Author(s):  
M. Kh. Kh. Alruishid ◽  
B. S. Dmitrievsky ◽  
A. A. Terekhova ◽  
A. A. Ishin ◽  
S. A. Skvortsov
Keyword(s):  
Natural Gas ◽  
Mathematical Models ◽  
Steam Reforming ◽  
Kinetic Models ◽  
Adsorption Process ◽  
Hydrogen Adsorption ◽  
Gas Mixture ◽  
Numerical Studies ◽  
Model Complex ◽  
Model Equations

The problem of approximation of kinetic models of adsorption by equilibrium models with fictitious coefficients of linear isotherms is set and solved. A complex of two mathematical models of the hydrogen adsorption process and an algorithm for calculating model equations has been developed. Numerical studies of the adsorption process of a multicomponent hydrogen-containing gas mixture have been carried out.

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