Dynamics Of Transportation And Chemical Interaction Of Hydrothermal Fluids: Modeling, Software And Application

The dynamics of ore-forming processes is an important branch and academic direction of the dynamics of geochemistry. It is too a new academic direction in the theory of origin formation of deposit and geochemistry of deposit. Go on research the dynamics can enrich dynamics of geochemistry and develop theory of geochemistry and promote the content of geochemistry. It is a approach of natural and a reflection of certain degree that continuous medium model combined heat-mass transportation, interaction and the formation model of mineral deposit by Invading of magma. The research on the dynamics of ore-forming processes can detect the essence of ore-forming processes, make mineral deposit's study from static to dynamic, from determining the nature to ration, and can break-through the traditional theory of origin formation of deposit. At the same time with development of the research have important significance for predicting deposit and exploiting the mineral resources. In porous medium, heat mass often take dissolve or precipitate processes. We cared very much is, what environment and mineralize mechanism of dissolve or precipitate processes on dynamics controlling. It act an important meanings for studying the forming of the deposit, especially large-scale, ultra large-scale forming of deposit. For setting up the mathematics model of mineralize on dynamics control, this text discuss simple situation, namely, chemical model of the Quartz (solid) with water take interaction and produce the silicic acid (liquid). Set up a component equation include dynamics equation of the flow, spread, chemical reaction in heat mass. We base our subgrid-scale porosity and permeability models on a spherical close pack arrangement of grains. Grains grow via precipitate, less via dissolve. When the solution in the area is the supersaturated solution, the solute will be precipitated, and increases radius of grains. When the solution is un-saturated, it takes place phenomenon of dissolving, and less the radius of grains. Thus, we set up a model about radius of grains RN to solute concentration(0.1). We define ε =R_N R_o^I( 1 ≤ ε ≤1.1547=2/(3^1/2)),which is the ratio of the effective grains radii to the radius of the nonoccluded close pack.. The porosity is (0.3). We used the Kozeny-Carman equation as the permeability to porosity relation, which for our close pack model becomes (0.4). By the change of radius, the porosity and the permeability will too change. Use the law of quality invariable, law of energy invariable, continuity equation of fluid, and Darcy's law, state equation of the fluid, we set up dynamics differential equation model of coupling with the Heat Mass transport -interaction. The dynamics differential equation, include the Darcy's law (0.5), the streamline equation (0.6), the heat equation (0.7), the total concentration of solute equation (0.8), the state equation of the fluid (0.9). For seeking steadily, practical numerical method about the dynamics differential equation model, have important theory and actual meaning. A lot of scholars for numerical method carry on a large amount of research. Through analyzing these methods, we find the error of computing technology is mainly error of approach. Since that do the mathematical solve of question is unrealistic one in entirely area, we hope do the mathematical solve in some units of local. And reduce the error of approach, and get the result which littler calculating and precision highly, with stability computing technology etc. This text by using the mixed finite analytic method to solve the dynamics differential equation. First, we will from of equation (0.6), (0.7), (0. 8), unify a form of the two-dimensional equation (0.10). Next we discuss the solving of the equation (0.11), it equal to (0.12). This text discuss the mixed finite analysis format (0.12) approach to equation (0.11) and the error of truncation of the format is O (Ï„ 2 +h2), and the solution of the equation (0.12) is exist, only and absolute stability. We study the format of the mixed finite analysis for the two-dimensional equation (0.10). Its format of calculating is (0.13). All method have the error of discrete, it not only influences the precision that numerical method, but also the numerical method effect the domino effect of the physics, the serious will influences the authenticity of solution. This text has discussed the numerical effect of the mixed finite analysis method. This numerical effect of format will reduce with increase that counts of the network, when the counts of the network greater than 10, and the Courant's number C keep in 0.8¹.3, then the solution guarantee the number's frequent wavelength of the Fourier's function keep loose lesser than 5%. The mixed finite analysis method base on area of regular rectangle domain, but real fluid is mostly carried on in the complicated irregular space area. This text will vary the irregular space area to regular rectangle domain by boundary-fitted coordinate system. For solving the dynamics differential equation, the author has finished the software of the Dynamical of Coupled with the Heat Mass transports -interaction. This software about 6500 source code, assign to three pieces of module: input module, solution module and module of result export. In the input module, include choice software work path, copy the data from geological figure, and the parameter values of the medium, fluid, border condition and initial. In solution module, need to determine the essential operation parameter values, for instance, number of the networknode, time-step and total running time, etc. In module of result export, output the result of variable about the temperature, concentration of solute, the permeability, the precipitating amount and so on. This software use the Surfer software output result of stage at last, thus the lowest running environment of the software is: Windows 98, IE browser 5.0, the memory of 64 M, CPU above 166MHz, and install surfer 7.0, hard disk have free space over 20 M. For better describing dynamics process, we must to simulate the ore-forming dynamics process. We give three kinds of models for this reason, want to simulate the temperature, the concentration of solute, and the permeability of the process, etc. We will detailedly study three kinds of model. In model I, we known radius distribution of medium grains, and full of the solution of saturation in the medium, under the normal geothermal gradient, pieces of temperature perturbation that produce for a certain reason (changed by the radioactivity or the chemical reaction, etc.). Thus it lead to the dynamics process of heat mass transportation and chemical interaction in the area. The model II simulate a process of magma's (or rock-branch) invading along certain crack channels. So condition of simulation is that it has very little high temperature zones. In the high temperature zones, The medium is full of solution of saturation, has lower the permeability and the porosity The model III simulate a process of magma's invading, which in the bottom of the field lying one heavy concealed rock body and in middle of the field there is a rock-branch. In the bottom and rock-branch have high temperature high concentration, lower the permeability and the porosity. All models, we assume the streamlines keep value 0 on the all border. The temperature keep a constant on top border, keep free on other three border, The temperature of initial is defined according to the normal geothermal gradient except that prove specially. The concentration of initial is constant. The condition of border the concentration keeps the same with border condition of the temperature. According to these three models, we have following understanding: a) Coupling of between temperature's localization change and grain size distribution un-homogeneous can break systematic equilibrium and make the system carry on the dynamics process of heat mass transportation and chemical interaction for a long time. b) The dynamics equation has self-organization criticality structure. c) Only invading of little rock-branch, the system doesn't keep high temperature for a long time at time, and doesn't benefit to form large-scale deposit and the precipitate of SiO2 is only 0.8 kg/m3. It isn't enough to ore-forming. d) The dynamics has feedback effect and hysteresis, and make the process of dissolution and precipitation non-linear reaction, namely, the structure of time rhythm. e) The system for model III, mineralization area is under of the earth's surface 100-250 m, andboth sides center of chunnel. Besides, SiO2 up to more than 250 kg/m3 and about 10% as much as medium content, so enough to form and extensive development silicate. f) About the large-scale, super-huge mineral deposit (Yinshan's multi-metalliferous deposit), is explained rational that under-part of the filed has a heavy rock-base, Its enormous heat energy and ore-resource can make the system interaction for long time and become possible a large mineral deposit. In conclusion, the research has significance for detecting the essence of ore-forming processes, predicting deposit and exploiting the mineral resources.