Radial Model of Steam Extraction from a High-Temperature Bed by Means of a Single Well

Alkhasov, A. B.; Рамазанов, М. М.

doi:10.1007/s10891-014-1045-x

Cited by 5 publications

(10 citation statements)

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“…At the same time, the plane model may turn out to be inapplicable in the vicinity of wells, and a radial-symmetrical model will be more adequate. This assumption has really been confi rmed, and, as has been found, the critical permeabilities for the plane and radial models may differ only by several orders of magnitude [8].In the present work it is shown that the differences in the indicated models can not only be quantitative, but also qualitative. In the plane one-dimensional model the front of boiling moves precisely infi nitely long according to the root law and goes off to infi nity (for an infi nite bed) if the frontal regime of heat and mass transfer originates and comes up to a selfsimilar solution.…”

supporting

confidence: 80%

Section: Introductionmentioning

confidence: 61%

“…In what follows, we have derived this dependence and present a diagram of various regimes of heat and mass transfer in the radial-symmetrical case considered. From the present work and from work [8] it follows that the application of the results of plane model to geothermal beds calls for caution. …”

mentioning

confidence: 69%

“…Many researchers [3,[8][9][10][11][12][13] were engaged in mathematical simulation of the processes of motion of liquid and gases in geothermal systems on the basis of the mass and energy balance equations and Darcy law for two-phase fi ltration. A brief critical review of these works is given in [7] where the problem on two-phase fl ow with phase transitions in a porous medium was posed most sequentially and rigorously.…”

Section: Introductionmentioning

confidence: 99%

“…The solution obtained describes the frontal regime of heat and mass transfer during steam extraction from a high-temperature bed. However, this regime is not the only one that can take place in the course of steam extraction, but, as shown in [8] and considered in more detail below, is the least typical of the geothermal collector in service. The present work is a sequel to [8], and one of its basic results is the proof that the boiling front comes to a halt on having covered a certain distance.…”

mentioning

confidence: 99%

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Frontal Regime of Heat and Mass Transfer in a Geothermal Bed

Alkhasov

Рамазанов

Alkhasova

2015

J Eng Phys Thermophy

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Based on an earlier proposed mathematical model, the conditions for the existence of a frontal regime of steam extraction from a high-temperature bed have been derived. It is shown that unlike the familiar one-dimensional case, in the radial-symmetrical model considered the radius of the region occupied by steam tends to a limiting value, that is, the front of boiling that separates the regions of water and steam practically comes to a stop after a time. A formula has been derived pointing clearly to the dependence of the indicated limiting value of the front radius on the water and steam parameters as well as on the characteristics of the geothermal bed. It is shown that for the steam to occupy a considerable region around the well when the bed is in service, it is necessary that the initial state of water be close to that of steam generation. Otherwise the front of boiling in the considered regime of heat and mass transfer extends from the well only a little.Keywords: steam generation in a bed, heat and mass transfer, fl ow regimes, radial model, analytical solution. Introduction.In the past few years, a sharp increase in the use and in the areas of utilization of the geothermal resources of the Earth has occurred. In the energy balance of a number of countries, the geothermal power engineering technologies become dominant, with the share of geothermal power engineering in the world energy balance increasing steadily. Geothermal resources of different temperatures are widely used in electrical power engineering, power-and-heat generation, industry, and in other areas. The up-to-date power engineering technologies using geothermal resources are distinguished by ecological purity and, as concerns their effi ciency, they are approaching the traditional ones.Monographs, reviews, and papers [1-8] are devoted to the problems dealing with the extraction and utilization of a geothermal energy. Many researchers [3,[8][9][10][11][12][13] were engaged in mathematical simulation of the processes of motion of liquid and gases in geothermal systems on the basis of the mass and energy balance equations and Darcy law for two-phase fi ltration. A brief critical review of these works is given in [7] where the problem on two-phase fl ow with phase transitions in a porous medium was posed most sequentially and rigorously. This work also considers a plane one-dimensional problem, which made it possible to fi nd a simple self-similar solution. In particular, a diagram of various regimes of fi ltration has been drawn. At the same time, the plane model may turn out to be inapplicable in the vicinity of wells, and a radial-symmetrical model will be more adequate. This assumption has really been confi rmed, and, as has been found, the critical permeabilities for the plane and radial models may differ only by several orders of magnitude [8].In the present work it is shown that the differences in the indicated models can not only be quantitative, but also qualitative. In the plane one-dimensional model the front of boiling moves precisely...

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supporting

confidence: 80%

Section: Introductionmentioning

confidence: 61%

mentioning

confidence: 69%