Liquid MHD - generator (bezmashinny means of converting thermal energy into electricity) Print E-mail
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Written by Хамзя Умяров   
Friday, 20 March 2009
 Transferred via translate.google.com
The text of the original in Russian 


Current methods for obtaining electrical energy from fossil fuels is quite complex, as well as in heat engines requires an intermediate conversion of energy, and such facilities - expensive and bulky. Reciprocating engines, gas turbines and jet engines a simple steam plant, since there is no intermediate working body - a pair, for which the required additional equipment (boiler, condenser, 
  pumping facilities, etc.), which is related to the cost of energy. However, these engines of thermal energy is converted into mechanical and then into electricity. Also, complex installations and other types (hydraulic turbines, nuclear plants, etc.), so it has long been an issue on development of new methods for obtaining electrical energy without intermediate transformations. Currently, a great interest in methods of direct generation of electricity, as thermionic (thermionic) thermocouple; magnetohydrodynamic (magnitogazodinamichesky) electrochemical (fuel cell). 

Let magnetohydrodynamic method for direct conversion 

thermal energy into electricity. Existing magnetohydrodynamic generators (MHD generators), the basis of which the working body - gas, heated to temperatures of several thousand degrees, becoming ionized plasma and a good conductor of electricity (including, as additives in the form of potassium carbonate or cesium salts) - should be called magnitogazodinamicheskimi. 
  But it is possible to design and create exactly magnetohydrodynamic generators, the work of a working body which are specially prepared liquid solutions. In particular, gas-liquid dispersion, while the 
  them - the dispersion in suspension. The advantage of the latest is that there is no need to have high-temperature gas environment, the complexity of the retention of which in a closed volume leads to large heat losses and, as a rule, in a sharp decline in efficiency of up to 40%, while theoretically permissible, that the method of direct conversion of thermal energy capable of electrical efficiencies of 65 ... 70%. 
  The idea of fluid MHD generators are not new. As early as 1974 in the book «Technical thermodynamics» academics, authors, USSR Academy of Sciences Kirillin VA, Sychev VV and Sheyndlin AE noted: «In addition to the MHD generator in which an electrically-environment is used partly ionized gas, are considered the scheme of MHD facilities, the working body of which are liquid metals (usually alkali metals such as sodium, and some others). Much higher electric conductivity of liquid metal (in 4-5 orders of magnitude higher than the partially ionized gas) you can get more power at relatively low speeds in the liquid metal MHD generator. Efficiency of liquid-metal MHD systems are markedly lower than plasma installations, primarily because of low cost ways to accelerate the liquid metals, for example, through injection, but the size of the installation at the expense of much greater specific power and application to ensure the circulation of gas device that is not moving parts (electromagnetic pump instead of a big compressor), make the liquid metal MHD generators attractive in some cases (such as transportation power plants) ». 
  Another important feature, in theory, hinder the achievement of acceptable values of efficiency, is that the channel of MHD generator have to be located in a magnetic field. As is well known from electrodynamics, while crossing a conductor of power lines magnetic field in the conductor occurs electromotive force (in particular, in the usual electric e.d.s. in the rotor winding occurs at the intersection of the rotor winding conductors of power lines magnetic field formed by the stator electromagnets). 
  A well-known effect of the Einstein-de Haaza, which is widely used in modern high-electronic technology, the essence of which is that when magnetizing ferromagnetic acquires rotational moment about the direction of magnetization (A. Einstein and Dutch physicist W. De Haaz, 1915). Much less known and less common effects of Barnett (1909) - the opposite effect of Einstein-de Haaza - the essence of which is that the rotation of a ferromagnetic sample increases its magnetization along the axis of rotation. 
  Barnett effect in combination with the effect of Merkulova can begin development of a new method of direct conversion of thermal energy into electricity, ie, fluid MHD generators. It is based - low heat (gas with a temperature 
  than or equal to 200 ª C) and solutions based on compounds such as iron. This technology will provide fully gas-liquid dispersion in suspension, where the jet in the interaction with the magnetic field installation, creates within the flow e.d.s., to which, in turn, in a closed external circuit installation potechet electricity. The advantage of this method of direct conversion of thermal energy to electricity would be the lack of high-temperature environments, the complexity of the retention of which in a closed volume, not allowed to bring the efficiency of MHD-generation to values close to theoretical. In addition, such liquid MHD generators will be cheaper, simpler and more compact in comparison with magnitogazodinamicheskimi. 

  Here it is necessary to refer to the work of Professor Samara State University, doctor of technical sciences, head of the Laboratory of O 'Neill-9, AP Merkulova, who first tried to use as a working body fluid (water) in a well-known construction of vortex tubes Ranko - Hilsha. These results are interesting to them that the water passed through the device actively filled steam bubbles of different diameters (I have this experience repeated and fully confirmed). On the stability of the obtained gas-liquid mud AP Merkulov said nothing. But the suggested mechanism of formation of bubbles. 
  In his view, the boundary (wall) layer promoted the flow of fluid shear forces operate at both the elementary volume of fluid that occurs mikrovihrevoe education along the axis parallel to the wall. Under the influence of centrifugal force along the axis of a vacuum, which instantly filled with pairs of liquids and gases contained in the liquid. 
In consideration of the proposed design of the installation, the idea of AP Merkulova added so that the cylindrical wall bordering promoted the flow of fluid subjected to elastic low-frequency mechanical vibrations. That is, the wall performs oscillatory motion, velocity, which from time to time - it coincides with the linear velocity of swirling flow, then directed in the opposite direction. 
  If AP Merkulov rights in their assumptions, in this case created almost ideal conditions for the emergence of myriad untwists elementary volumes of liquid. Approximate calculations show that, for example, the elementary volume of fluid that has a square cross-section with sides of 10 microns, with the estimated amplitude of fluctuations in the wall of 0,3 mm, raskruchivayas, is the frequency of rotation in the millions (!) Revolutions per minute. 
  Emerging with the centrifugal forces acting on the fluid, so great, that along the axis of rotation necessarily formed emptiness fusiform shape, instantly filled by pairs of liquids and gases contained in the liquid. 
Because the scope of the best optimum ratio between the volume and its surface, then in the end, education becomes fusiform spherical shape, ie, the form of bubbles. In fact, in the presence of liquid inclusions, a feature which is that they have their own angular momentum. In quantum mechanics this is called spin. Even if we imagine that up to full rotational damping moment requires a few seconds, then when that time is sufficient to mix the effects of Barnett and Merkulova themselves with the passage of fluid through the power line magnetic field formed by the stator electromagnets. That is, in the stator winding of a different e.d.s. 

  The source of low-thermal energy can become outgoing gas engines, gas turbines and boilers of numerous heating plants. 
  Indeed, the temperature of gas, usually does not exceed 200 ° C. However, if 1 MW of thermal payload of natural gas burned in the atmosphere of about 1500 cubic meters of gas. This «wasteland» heat and can be used for electricity generation liquid MHD generator. If we imagine that the efficiency of such bezmashinnogo direct thermal energy conversion to electricity is, for example, 50%, then the use of 1500 cubic meters. meters of gas can be obtained from the electrical power value of 40 ... 50 kW. But now the power of urban heating plants have measured hundreds of megawatts. For example, in Moscow there are a number of district heating stations (RTS), whose capacity exceeds 500 MW. 
  The Moscow City Government in addressing issues of improving the efficiency of the fuel and energy complex of the city, is on the way force development, so-called cogeneration. That is, in the existing RTAs established gas turbine installation (GAC), produce electricity, heat of exhaust gases by means of exhaust-heat boilers used for heating and hot water. This provides significant savings in fuel resources. 
  From these lines a little work on the RTS in Moscow Penyagino. Thermal power RTS is about 600 MW. In addition to the boiler, there are two sets of gas turbine cogeneration. They are two «simensovskie» turbines to 25 MW each. But the direct conversion of heat about 850 thousand cubic meters of gas (per hour) of electricity can provide more, at least 30 MW of electrical power. If the cost of each turbine is $ 7000000, the liquid MHD generators will cost much less. But most importantly here - air emissions can be reduced to zero, which significantly affect the environment megapolis. Yes, and efficient use of fuel resources, a marked increase.  
 

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