In this work, the authors thermodynamic equilibrium calculations developed a computer program in MATLAB of vapor-liquid multicomponent phases below the language for aqueous speciation and critical temperature of wat...In this work, the authors thermodynamic equilibrium calculations developed a computer program in MATLAB of vapor-liquid multicomponent phases below the language for aqueous speciation and critical temperature of water （647 K） and pressures up to 2 kilobar with two computational routines. The first routine calculates the aqueous speciation from the equations of mass balance, charge balance and mass action, forming a system of N equations and N unknowns describing the aqueous phase with N unknown chemical species, which is solved with Newton-Raphson method using the Debye-Hiickel and Bdotactivity coefficients that solved simultaneously with Henry＇s Law, the Soave-Redlich-Kwong equation of state and a Poynting correction term, calculate chemical potentials and composition of the phases of the system, which are used at the Ratchford-Rice flash routine that iteratively recalculates the distribution of gases in liquid, until convergence. The chemical composition data of gas and brine phases of production wells at standard conditions for 1998 and 2007 of the Los Humeros geothermal field are modeled in the described manner, deducing that fluids inside the pipes of the reservoir are corrosive and cause the precipitation of newly formed minerals such as iron and calcium sulfates and silica, at reservoir conditions.展开更多
To simulate the soil moisture variation in cropland, a two-parameter exponential recession model was derived to depict the recession process of soil moisture in the root zone. The model is based on the assumption that...To simulate the soil moisture variation in cropland, a two-parameter exponential recession model was derived to depict the recession process of soil moisture in the root zone. The model is based on the assumption that the recession rate of soil water is proportional to the potential evapotranspiration rate and the difference of soil water content and steady soil water content. Two parameters in this model are soil texture-dependent recession constant and steady soil water content. The model was calibrated and validated with measured soil water data at two experiment sites in North China with different soil textures and cropping systems. Coefficients of determination between measured and model simulated soil water content were all greater than 0.7, indicating that both models gave satisfactory simulation results. Results showed that values of two parameters mentioned above are both larger for finer soil than those for coarser soil. At the same potential evapotranspiration rate and soil water content, the recession rate of finer soil is usually lower than that of coarser soil. The proposed model can be used in irrigation management to predict approximate date for irrigation, as well as be embedded into watershed hydrological models to estimate the antecedent precipitation index.展开更多
文摘In this work, the authors thermodynamic equilibrium calculations developed a computer program in MATLAB of vapor-liquid multicomponent phases below the language for aqueous speciation and critical temperature of water （647 K） and pressures up to 2 kilobar with two computational routines. The first routine calculates the aqueous speciation from the equations of mass balance, charge balance and mass action, forming a system of N equations and N unknowns describing the aqueous phase with N unknown chemical species, which is solved with Newton-Raphson method using the Debye-Hiickel and Bdotactivity coefficients that solved simultaneously with Henry＇s Law, the Soave-Redlich-Kwong equation of state and a Poynting correction term, calculate chemical potentials and composition of the phases of the system, which are used at the Ratchford-Rice flash routine that iteratively recalculates the distribution of gases in liquid, until convergence. The chemical composition data of gas and brine phases of production wells at standard conditions for 1998 and 2007 of the Los Humeros geothermal field are modeled in the described manner, deducing that fluids inside the pipes of the reservoir are corrosive and cause the precipitation of newly formed minerals such as iron and calcium sulfates and silica, at reservoir conditions.
基金Under the auspices of National Natural Science Foundation of China(No.51279077,91125017)
文摘To simulate the soil moisture variation in cropland, a two-parameter exponential recession model was derived to depict the recession process of soil moisture in the root zone. The model is based on the assumption that the recession rate of soil water is proportional to the potential evapotranspiration rate and the difference of soil water content and steady soil water content. Two parameters in this model are soil texture-dependent recession constant and steady soil water content. The model was calibrated and validated with measured soil water data at two experiment sites in North China with different soil textures and cropping systems. Coefficients of determination between measured and model simulated soil water content were all greater than 0.7, indicating that both models gave satisfactory simulation results. Results showed that values of two parameters mentioned above are both larger for finer soil than those for coarser soil. At the same potential evapotranspiration rate and soil water content, the recession rate of finer soil is usually lower than that of coarser soil. The proposed model can be used in irrigation management to predict approximate date for irrigation, as well as be embedded into watershed hydrological models to estimate the antecedent precipitation index.
