RU126229U1 - SOURCE OF ELECTRIC ENERGY OF SHORT-TERM ACTION ON THE BASIS OF MHD DC GENERATOR - Google Patents

Abstract

A short-term source of electric energy based on the MHD generator of a direct current contains a permanent magnet as a magnetic system, and a unitary fuel as a plasma-forming fuel. The device for starting the MHD generator is mechanical. These features allow you to create a fully autonomous device, the design of which is simple, compact and reliable, provides a long mode of readiness for work (months, years), is immune to external influences and is independent of environmental conditions. The implementation of current-collecting electrodes from a material providing a near-electrode voltage drop lower than the operating voltage of the MHD generator, and switching current-collecting buses according to a utility model, which excludes the weakening of the magnetic field of the permanent magnet, provide characteristics of the MHD generator that are acceptable for a number of applications — time to reach the operating mode ~ 0.1 s, operating time up to 10 s, electric power up to 100 kW.

Description

The utility model relates to sources of short-term electrical energy based on an MHD generator of direct current and can be used as a fully autonomous source of short-term electrical energy with a capacity of up to 100 kW with a long-term (months, years) readiness for operation and a time to enter the power generation mode ~ 0.1 s

Known MHD generators of short-term action with a resistive magnetic system on the products of combustion of solid (powder) plasma-forming fuel ["MHD generators of short-term action", Encyclopedia of low-temperature plasma, edited by V.E. Fortov, M., publishing house "Science", 2000, vol. IV, p. 162-164].

The main disadvantages of such generators are as follows:

- lack of autonomy, as To begin their work, it is necessary to create a primary magnetic field, much smaller than the working one, from an external source of electric energy immediately before the start of the operation of the MHD generator. Such a field is created by a battery of batteries or capacitors, to maintain the nominal characteristics of which they require recharging from an autonomous charger;

- a long time (1-2 s) for the MHD generator to reach the electric power generation mode associated with the establishment of a working magnetic field as a result of self-excitation;

- low efficiency generator, as a significant part (30-50%) of the electric energy generated in the MHD channel is spent on maintaining the magnetic field induction;

- a restriction on the duration of the interval between starts (≥10 hours) in the absence of a cooling system, associated with joule heating of the magnet winding material. The use of a cooling system will require an additional energy source for its power supply, which will make the MHD generator more bulky and further reduce its degree of autonomy.

The last three drawbacks are completely eliminated when a superconducting magnet is used instead of the resistive magnetic system in the MHD generator [RVDogadaev, V.P. Panchenko and others. “Compact MHD installation for generating powerful electric pulses”, Izvestiya RAS, Energetika, 2007 , No. 4, p.130-139].

However, a MHD generator with a superconducting magnetic system is also not autonomous because A magnetic field equal to the working one is created before the MHD generator is launched from an external source of electric energy and is kept constant for a predetermined time.

In such an MHD generator, the duration of entering the regime depends only on the time required to establish the plasma parameters, which for a unitary fuel is ~ 0.1 s.

The electric energy generated in the MHD channel is completely transmitted to the consumer without the expense of maintaining the magnetic field induction, which does not reduce the efficiency generator.

The limitation on the duration of intervals between pulses in a MHD generator with a superconducting magnetic system is not determined by the cooling time of the magnet winding, since the superconducting magnet winding is at a constant temperature, for example, at the temperature of liquid helium, does not heat up when current flows and, therefore, does not require heat removal from the winding.

This type of MHD generator is selected as a prototype. However, the indicated MHD generator is also not completely autonomous, because an autonomous low-power source, in addition to the function indicated above, is necessary for powering the cryogenic supply system of a superconducting magnetic system, especially its cryocooler and compressor.

The technical result achieved in the utility model is to ensure complete autonomy of the short-term electrical energy source on the basis of an MHD generator with acceptable electrical characteristics for a number of applications, to create a simple, compact and reliable design with long-term operational readiness, immunity to external influences and independence from environmental conditions.

The specified technical result is achieved by the fact that in the short-term electric power source based on the MHD generator of a direct current containing a combustion chamber with a container for plasma-forming fuel, a recharge device, a fuel igniter and a launch device, a supersonic nozzle, a linear Faraday MHD channel and a magnetic system to create a magnetic field in the MHD channel formed by two multilayer insulating walls, as well as the anodic and cathodic multilayer walls, at the sectioned current collection electrodes of the anode and cathode walls are connected to the corresponding current collection buses, a permanent magnet with a magnetic field induction of at least 0.5 T is used as a magnetic system, and a unit fuel is used as a plasma-forming fuel, providing a conductive supersonic plasma flow of at least 100 cm / m, the trigger device is made mechanical, the collector electrodes of the anode and cathode walls are made of a material providing near-electrode drop on at least 3 times less than the working voltage of the MHD generator, while one of the collector electrodes is connected to the corresponding collector bus, and the other collector bus of the other collector electrode is divided into two sections, each of which is directed along the corresponding insulating wall and perpendicularly opposite the electrode wall, above which these sections are connected with the formation of the third section, directed parallel to undivided into sections of the collector bus and located at the minimum permissible distance from the condition of electrical insulation.

The electrical characteristics of the MHD generator according to the utility model (operating time - up to 10 s, electric power - up to 100 kW, efficiency - a few percent) are acceptable for a number of applications, for example, as a source of electrical energy for powerful power starters installations (diesel engines, internal combustion engines, turbines) for powering inductive drives, magnets of powerful MHD installations, low-power emergency, backup or stabilization sources of electrical power for short-term operation.

Full autonomy of the device according to the invention is achieved through the use of a permanent magnet as a magnetic system, as a plasma-forming fuel - a unitary plasma-forming fuel and mechanical execution of the launch device. A permanent magnet creates in the volume of the MHD channel a time-constant magnetic field induction, the magnitude of which depends on the material of the magnet. The use of a unitary plasma-forming fuel, which already includes fuel, an oxidizing agent, and an easily ionizing additive, does not require a fuel component supply system.

The execution of current-collecting electrodes from a material providing a near-electrode voltage drop of at least 3 times less than the operating voltage of the MHD generator, and switching of the current-collecting buses according to a utility model provide the above electrical characteristics of the MHD generator.

The structural simplicity and compactness of the device are ensured by the use of an uncooled winding-free magnetic system based on a permanent magnet and a unitary plasma-forming fuel, which creates an electrical conductivity of the combustion products of at least 100 S / m.

The increased reliability of the MHD generator is associated both with a decrease in the number of structural units (windings and electric circuits of the magnet, cooling system, electric starting system, autonomous power supply), and the structural simplicity of the magnet, combustion chamber, fuel, and launch device.

The device can be in a long standby mode due to the existence of a magnetic field of a permanent magnet for a long time (months, years) and a guaranteed fuel resource (at least 10 years).

The simplicity and reliability of the design, the type of unitary fuel used, a permanent magnet, and a mechanical starting device ensure that the operation of the MHD generator is independent of the environment and external influences.

The source of electric energy according to a utility model is shown in FIGS. 1, 2, where in Fig. 1 is a structural diagram of a device in longitudinal section, in Fig. 2 is a cross-sectional diagram of a device with one of the busbar options of an MHD channel, namely, the division of the cathode collector bus into two sections.

In these figures:

1 - combustion chamber,

2 - a container with plasma-forming fuel,

3 - recharge device

4 - fuel igniter,

5 - launcher,

6 - supersonic nozzle,

7 - linear Faraday MHD channel,

8 is a permanent magnet

9 - multilayer insulating wall,

10 - anode multilayer wall,

11 - cathode multilayer wall,

12 - collector electrodes of the anode and cathode walls,

13 - anode collector bus

14 - cathode collector bus

15 - supporting frame.

A short-term source of electrical energy based on a MHD generator of direct current (FIG. 1) comprises a combustion chamber 1, which includes a container with plasma-forming fuel 2, a rechargeable fuel device 3, a fuel igniter 4, and a launch device 5. As a plasma-forming fuel located in the container 2 combustion chambers 1, a unitary fuel was used, which provided electrical conductivity of the supersonic plasma flow at the entrance to the MHD channel at least 100 S / m.

To ensure complete autonomy of the generator, the trigger 5 is made mechanical. A supersonic nozzle 6 is docked to the combustion chamber, which is articulated with a linear Faraday MHD channel 7 located in the working volume of the magnetic system based on a permanent magnet 8 with a magnetic field induction of at least 0.5 T. The MHD channel of rectangular cross section is formed by two multilayer electrical insulating walls 9, as well as the anode 10 and cathode 11 multilayer walls. The current-collecting electrodes 12 of the anode and cathode walls are made of a material providing a near-electrode voltage drop that is at least 3 times lower than the voltage between the electrodes of the anode and cathode walls of the MHD channel. Structurally sectioned electrodes 12 of the anode 10 and cathode walls 11 are connected to the corresponding current collection buses of the anode 13 and cathode walls 14. (Figure 2). The cathode bus is divided into two sections, each of which is directed along the corresponding electrical insulating wall and perpendicular to the opposite electrode wall, above which these sections are connected to form a third section, parallel to the current-collecting bus, which is not divided into sections and located at the minimum distance from the electrical insulation condition .

All of the above nodes MHD generator are connected in a rigid structure mounted on a support frame 15.

After completing the MHD generator, it may be in a state of readiness for work for a long time (months, years), because in its design, a unitary plasma-forming fuel, a permanent magnet, a mechanical starting device and an igniter are used, which have a long shelf life.

The MHD generator is turned on using the ignition device 5, which initiates the ignition of the igniter 4, which ignites the fuel in the container 2. A number of plasma-forming fuels, primarily solid (powder) fuels, do not require pre-start preparation and preliminary launch systems, go to the nominal combustion mode in time ~ 0.1 s and can be in constant readiness for work for at least 10 years. After ignition of the fuel in the combustion chamber 1 for a time of ~ 0.1 s, the specified pressure, temperature, plasma properties and the flow rate of the combustion products through the supersonic nozzle 6 and the MHD channel are established. Since the magnetic field in the MHD channel is constant, when a plasma stream appears In the MHD channel, “instantaneous” (with a delay of ~ 10 ^–3 s) generation of electric power occurs.

The current generated in the MHD channel is diverted directly to the load or to the electric energy converter from the collector electrodes 12 located on the anode 10 and cathode 11 of the channel walls using the anode 13 and cathode 14 of the collector buses (FIG. 2). In this case, the connection of the electrodes and the removal of current from the MHD channel are carried out according to a scheme that eliminates the weakening of the magnetic field of the permanent magnet in the MHD channel. As mentioned above, one of the collector electrodes is connected to the corresponding collector bus, and the other collector bus of the other collector electrode is divided into two sections, each of which is directed along the corresponding electrical insulating wall and perpendicular to the opposite electrode wall, above which these sections are connected to form the third section directed parallel to the collector bus which is not divided into sections and located on the minimum electrical isolation condition distance from her.

In one embodiment of current drainage from the MHD channel, the sectioned current collection electrodes 12 of the anode wall 10 are connected to the anode current collection bus 13. The cathode current collection bus 14 is divided into two sections, each of which is directed along the corresponding electrical insulating wall 9 and perpendicular to the anode wall 10. These sections connected to the third section above the anode wall 10 (Figure 2). The third section of the bus 14 is parallel to the anode collector bus 13 and is located at the minimum distance from it from the condition of electrical insulation.

Since the currents in the sections of the cathode current collection bus flow opposite to the currents in the plasma of the MHD channel, the “z” components of the magnetic field induced by them and currents in the plasma are largely compensated and therefore do not weaken the magnetic field in the working volume of the channel created by the permanent magnet. Since the parallel sections of the collector bars 13 and 14 above the anode wall are located extremely close to each other, the currents in them are equal and flow in opposite directions. Consequently, according to the law of the total current, the magnetic fields induced by them compensate each other and, thus, do not distort the magnetic field of the permanent magnet in the channel.

Another option for removing current from the MHD channel is to reverse the busbar of the anode and cathode walls of the MHD channel.

The described switching of the electrodes and slip rings of the MHD channel provides the specified electrical characteristics of the MHD generator, the values of which can vary in the range from idle to short circuit.

To reduce the near-cathode and near-anode voltage drops in the MHD channel, current-collecting electrodes 12 are used as part of the multilayer anode 10 and cathode 11 walls of a material providing a near-electrode voltage drop of at least 3 times less than the working voltage of the MHD generator, for example, pyrographite . In this case, the near-electrode voltage drop does not significantly affect the electrical characteristics of the MHD generator.

Thus, the device according to the utility model is a fully autonomous source of short-term electrical energy based on a MHD generator with a permanent magnet, the electrical characteristics of which are acceptable for a number of technical applications. Its design is simple, compact and reliable, provides a long mode of readiness for work, is immune to external influences and is independent of environmental conditions. The direct current generated by the MHD generator can be converted into alternating or direct current of a higher voltage using an electric energy converter based on inverters, rectifiers and transformers with efficiency ≥95%, which expands the possibilities of using the device according to the utility model.

Claims (1)

A short-term electrical energy source based on a MHD generator of a direct current containing a combustion chamber with a container for plasma-forming fuel, a recharge device, a fuel igniter and a launch device, a supersonic nozzle, a linear Faraday MHD channel and a magnetic system for creating a magnetic field in the MHD channel formed by two multilayer insulating walls, as well as the anode and cathodic multilayer walls, while the sectioned collector electrodes of the anode and the walls of the cathode are connected to the corresponding collector bars, characterized in that a permanent magnet with a magnetic field induction of at least 0.5 T is used as a magnetic system, and a unitary fuel is used as a plasma-forming fuel, providing a conductive supersonic plasma flow of at least 100 S / m , the trigger device is made mechanical, the collector electrodes of the anode and cathode walls are made of a material that provides near-electrode voltage drop of at least 3 times higher working voltage of the MHD generator, while one of the collector electrodes is connected to the corresponding collector bus, and the other collector bus of the other collector electrode is divided into two sections, each of which is directed along the corresponding insulating wall and perpendicular to the opposite electrode wall above which these sections are connected with the formation of the third section, directed parallel to the collector bus, which is not divided into sections, and located on the minimum admissible condition I have electrical isolation distance from her.

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