RU2170998C1 - Method and device for building up inverse population in carbon dioxide gas-dynamic laser - Google Patents

Abstract

FIELD: laser engineering. SUBSTANCE: method includes organization of fluid mixing of components in subsonic section of nozzle so that gases were fully mixed up at monomolecular level in vicinity of critical section of nozzle. Parameters of gases being mixed up are chosen and maintained in the course of reactions within desired range so as to organize conditions in which vibratory energy of molecules newly produced as result of chemical reactions in gas is accumulated in gas at low static temperature of gases and imparted to molecules of reacting gases thereby enhancing their reaction rate. Enhanced reaction rate, in its turn, causes further accumulation of vibratory energy in molecules of gas mixture ; in the process, CO is first to burn up and H, to lower extent. As a result, amount of vibratory energy accumulated in gas mixture of proposed laser active medium is much greater and water vapor content is lower at lower static temperature as compared with commonly used gas-dynamic laser. Device implementing proposed method has injector unit of combustion chamber mounted upstream of nozzle unit with its holes admitting cold gas component. Injector unit holes are arranged at optimal distance (L_opt) from critical section of nozzles found from equation L_opt= ud²/D_t, where u is flow speed of gas mixture in subsonic section of nozzle; d is typical size of injector unit; D_t is turbulent diffusion factor. Nozzle blades have central cooling-water passages joined to delivery and drain pipelines; subsonic section is provided with ducts having injector holes to admit cold gas component to main gas flow. Height and elevation of constant critical section of nozzle (h) should meet equation h < τ $\genfrac{}{}{0ex}{}{\text{2}}{\text{chim}}$ (u/ν)³D $\genfrac{}{}{0ex}{}{\text{2}}{\text{m}}$ , where τ_chim - is reaction rate of gases; u is gas mixture flow speed in vicinity of critical section of nozzle; ν is kinematic viscosity of gas mixture; D_m is molecular diffusion factor of gases being mixed up. EFFECT: enhanced efficiency of gas-dynamic laser. 8 cl, 4 dwg, 3 ex

Description

The invention relates to laser technology, in particular to devices for gas-dynamic CO ₂ lasers (GDL).

A known method of creating an inverse population of the active medium in a gas-dynamic CO ₂ laser due to the rapid expansion in a supersonic nozzle of a gas mixture of CO ₂ , N ₂ , H ₂ O (He) heated to high temperatures [1]. The disadvantages of this method include:
- The required high temperature of gases up to 2000 K and higher and, as a result, great difficulties with cooling and low resource of laser units.

 - Low gain of the active medium, low stored vibrational energy at the entrance to the resonator, low efficiency of the optical resonator and low specific energy consumption of radiation per unit gas flow.

 - It is practically impossible, based on this method, to create a cost-effective technological laser.

A known method of producing an inverse population in a gas-dynamic CO ₂ laser for producing an inverse population with selective injection of cold gas components (CO ₂ and He) through an injector in the critical section of a supersonic nozzle into a stream of nitrogen heated to a temperature of 3000-4000 K [2]. The disadvantages of this method include:
- The required high temperature of the gases is from 3000 to 4000 K and, as a result, very great difficulties with cooling the laser units, their low life.

 - The need for the availability of pure nitrogen and helium gases, which significantly increases the cost of operating the laser.

 - It is practically impossible, based on this method, to create a cost-effective technological laser.

One way to obtain an inverse population in a gas-dynamic CO ₂ laser is a method shown on the basis of the device, but not patented in the patent [3]. In this method, hydrocarbon fuel is burned in the combustion chamber with a lack of oxidizer, and air is blown into the injector located in the receiver in front of the nozzle block and CO and H _{2 are} burned in the vicinity of the nozzle critical section. There are the following disadvantages to this work:
- The characteristics of devices and parameters of miscible gases, at which the effect of increasing the stored vibrational energy in the active medium of the laser is not completely described and patented.

 - The physical phenomena leading to the effect of an increase in the stored vibrational energy in the active medium of the laser are not described.

- Numerous experimental studies of such devices in CO ₂ lasers have shown that not knowing the physics of the phenomenon and not fulfilling certain characteristics of the devices and parameters of miscible gases does not improve the characteristics of the active medium of the laser.

A typical device is a gas-dynamic CO ₂ laser operating on the products of combustion of CO and ethyl alcohol in oxygen with the addition of nitrogen and consisting of: a combustion chamber, a unit for mixing components, a receiver, a nozzle block, a flow part of a resonator, an optical resonator, and a diffuser [4]. Typical disadvantages of such a device of a gas-dynamic laser include:
- The required high temperature of gases up to 1700 K and higher and, as a result, great difficulties in cooling the laser units. In addition, the high initial temperature of the gases leads to large degrees of opening of the supersonic part of the nozzles and the high pressure of the gases in the receiver to ensure that the diffuser starts up when the exhaust gases are exhausted into the atmosphere, which, in turn, leads to high energy costs for gas compression.

 - Low gain of the active medium, low stored vibrational energy at the entrance to the resonator, low efficiency of the optical resonator and low specific energy consumption of radiation per unit gas flow.

 - The required small height of the critical section of the supersonic nozzle (0.3-0.4 mm), the associated difficulties in cooling the nozzle blades and the deterioration of the characteristics of the active medium during operation. In addition, with a small height of the critical section of the nozzles, even for a typical degree of opening of the supersonic part of the nozzle ~ 30, the thickness of the nozzle blade in the maximum section does not exceed 11-12 mm, which does not provide its predetermined structural rigidity. During the operation of the laser, the blades are subject to vibrations, they quickly deform, collapse, and the characteristics of the active medium deteriorate (the radiation power decreases by a factor of 1.5–2).

 - The large required length of the flow path of the resonator along the gas flow, the associated deterioration of the characteristics of the active medium, and the need for a high gas pressure in front of the nozzle block to ensure that the diffuser starts up when the exhaust gases are exhausted into the atmosphere.

 - The high cost of operating such a technological laser.

 A device is known for an electro-gas-dynamic CO laser, which includes: a discharge unit, a mixing unit, a nozzle unit, a flow part of a resonator, an optical resonator, a diffuser, an energy unit in the form of a turbocompressor, and an electric generator operating from a turbocompressor shaft [5, 8]. The working fluid in this device is the products of combustion from turbine gas generators, in addition, air is taken from the compressor and supplied to the mixing unit of the laser, and the exhaust gases from the laser are fed to the turbocompressor inlet through the heat exchanger. The disadvantages of this device include the fact that in the combustion products of typical turbine chambers there are many soot particles that significantly impair the operation of the discharge block, mirrors of the optical resonator, and reduce the output power of the laser radiation and the service life. In addition, the CO laser requires that the static temperature in the cavity zone not exceed 100 K (in this case, the gas temperature at the inlet of the nozzle block is at least 1500 K), and this leads to a high degree of opening of the supersonic part of the nozzles, the need for low static pressure in the zone resonator, a large degree of gas ejection of a turbocompressor and, as a result, the very high cost of operating such a laser.

 A device for an optical resonator of a high-power laser [6] is known, which is made of 4-pass, 6-mirror with two angular reflectors, which ensures that the radiation beam flips over the gas flow in the resonator flow zone at each radiation pass between the mirrors in such a way that on one side the gas flow of the active medium is a large corner reflector, and on the other side of the medium is a block of mirrors, including a small corner reflector, an output convex and rear concave mirrors, while the edges of the corner reflectors are times eschayut perpendicular to each other.

Closest to the present device in terms of the composition of the units and assemblies included in the gas-dynamic CO ₂ laser is the device described in [7]. The laser device includes: containers for storing the initial components of the working mixture of gases or fuels; compressors and component feed pumps; heating device or fuel combustion chambers; receiver; a nozzle block recruited from flat nozzle vanes; flow part of the resonator; optical resonator; diffuser; exhaust system; cooling system compressor; refrigerant storage capacity; heat exchanger; gas-dynamic window for outputting laser radiation from the cavity.

The disadvantages of this prototype should include all the disadvantages described above for the analogue of [4]. In addition, when creating technological lasers based on GDL of this type, the following difficulties arise:
- The high temperature of the working gas mixture leads to additional energy costs for cooling the nodes and their low service life.

 - Large acoustic and dynamic effects on the resonator mirrors and the environment.

 - High fuel component costs and high cost of operation of the device.

The aim of the invention of a new method for creating an inversion of the active medium of a gas-dynamic CO ₂ laser is:
- A significant improvement in the characteristics of the active medium of a CO ₂ laser: an increase in the gain, the stored vibrational energy, the efficiency of the optical resonator, and the output radiation power (not less than two times).

 - A significant reduction in the initial temperature of the mixing gases and, therefore, an improvement in all the technical characteristics of devices using this method.

- The ability to create cost-effective technological CO ₂ - GDL.

The proposed method for creating an inverse population in a gas-dynamic CO ₂ laser at low temperatures is based on the fact that, in the general case, the rate of the chemical reaction of the formation of CO ₂ molecules depends not only on the static temperature of the gas mixture, but also on the vibrational temperatures (internal energy) entering between themselves into the reaction of gas molecules.

 In a mixture of reacting gases containing a buffer, neutral gas, under optimal parameters and certain conditions, the following flow diagram of physicochemical processes is possible. The newly formed gas molecules, which are the product of the reaction of the reacting components, transfer part of the vibrational energy stored in them during the chemical reaction when they collide with the buffer, neutral gas molecules in which this energy accumulates. Then, when the buffer gas molecules collide with the molecules of one or more reacting gases, they transfer part of the stored vibrational energy, transferring them to an excited state and increasing the vibrational temperature of the molecules. In this case, the rate of chemical reactions increases sharply, a greater number of gas molecules are produced, which is a reaction product, the amount of stored vibrational energy increases, which is transferred to molecules of reacting gases in a larger volume. Thus, an avalanche-like process of accelerating reactions at low static temperatures occurs, leading to explosive combustion.

 Under certain conditions, one of the reacting gases can also be used as a buffer storage of vibrational energy, but in this case, its initial concentration should be high, and as this gas is consumed during reactions, the effect of an avalanche-like acceleration of reactions stops and the reaction gases do not burn out completely. In order for such a reaction to occur, it is necessary to select a suitable buffer, neutral gas and supply reacting and buffer gases to the mixing device with the specified optimal parameters, and create certain conditions in the monomolecular gas mixing zone described below.

Consider this as an example of the gross reaction 2CO + O ₂ + N ₂ = 2CO ₂ + N ₂ in the presence of hydrogen or water vapor. The buffer gas N ₂ added to the mixture of reacting gases CO and O ₂ has a characteristic temperature of the lower vibrational level of 3354 K, which is close to the lower vibrational level of the antisymmetric mode (001) of the carbon dioxide molecule CO ₂ (3380 K), which is the product of the reaction of CO gases and O ₂ . At the same time, the lower vibrational level of the N ₂ molecule is also quite close to the lower vibrational level of the combustible CO molecule (3084 K).

Such a close arrangement of the vibrational levels of the molecules of these gases allows one to fundamentally accumulate vibrational energy from newly formed CO ₂ molecules in nitrogen and transfer it to combustible CO molecules for times shorter than the relaxation times of vibrational energy from CO ₂ , CO, N ₂ molecules. In addition, at high concentrations, CO can also serve as a storage gas of vibrational energy.

The goal is achieved:
1. In the subsonic part of the nozzle, jet mixing of all components is organized so that complete mixing of the gases at the monomolecular level occurs in the region of the critical section of the nozzle.

Here the requirement is put forward for very fast, intensive mixing of turbulent moles of gas components in the subsonic part of the nozzle at the optimal minimum length, so that the final mixing of gases at the monomolecular level in turbulent moles occurs in the region of the nozzle critical section. This will create the conditions for the formation of a flat flame front (combustion zone) in the region of the critical section of the nozzle, while certain requirements are put forward for the characteristics of the flow of miscible gases, the injection device and the critical section of the nozzle. If the required conditions are not created, then partially the CO oxidation reaction can occur on the surfaces of turbulent moles of gas in the subsonic part of the nozzle, the vibrational energy of the newly formed CO ₂ molecules relaxes in heat, its accumulation in nitrogen does not occur, and a self-accelerating reaction does not occur.

 2. The parameters of the miscible gases are selected and maintained during the course of the reaction in a given range, based on the conditions that the conditions are met in the mixing zone of the components at the monomolecular level in the region of the nozzle critical section.

 a) The mixing time of the components at the monomolecular level was no more than the time of chemical reactions between the molecules of the reacting components.

 In this case, a natural requirement is put forward that gas mixing at the monomolecular level is faster than the rates of chemical reactions. Otherwise, the stored vibrational energy in the molecules due to chemical reactions will have time to relax and a self-accelerating reaction will not work.

b) The time of chemical reactions of the formation of a CO ₂ molecule was no more than the relaxation time of the vibrational energy of the CO ₂ molecule.

This condition means, for example, that the rate of formation of CO ₂ molecules in the reaction should be greater than the rate of relaxation of the vibrational energy of the same molecule after its formation and should allow the accumulation of vibrational energy.

c) The time of transfer of vibrational energy from the lower vibrational level 001 of the CO ₂ molecule to the lower vibrational level of the N ₂ molecule should be no more than the relaxation time of the vibrational energy of the CO ₂ molecule.

This requirement implies that when a newly formed vibrationally excited CO ₂ molecule collides with nitrogen molecules due to the Fermi resonance and the selected initial parameters of the mixture, conditions are created when a large fraction of the vibrational energy is transferred to nitrogen. In the case when a reactive component (CO) is used as a storage of vibrational energy, the above requirement is advanced to it.

d) The relaxation time of the vibrational energy of the molecule N ₂ and (or) CO must be not less than the relaxation time of the vibrational energy of the molecule CO ₂ .

This condition corresponds to the fact that due to the selected gas parameters, conditions are created for the transfer of vibrational energy from newly formed CO ₂ molecules to nitrogen or to CO and its accumulation in them.

d) The time of transfer of vibrational energy from the lower vibrational level of the N ₂ molecule and (or) from CO ₂ to the lower vibrational level of the CO molecule should be no more than the relaxation time of the vibrational energy of the N ₂ and CO molecules.

This condition means that in the collision of molecules of combustible CO with nitrogen molecules, a significant fraction of the stored vibrational energy in N ₂ must be transferred to CO molecules, or in the absence of a buffer gas, vibrational energy is transferred directly from CO ₂ molecules to CO molecules.

f) The relaxation time of the vibrational energy of the CO molecule must be not less than the duration of the entire chain of chemical reactions of the formation of the CO ₂ molecule.

This requirement is necessary so that after the transfer of vibrational energy from nitrogen to CO, vibrationally excited CO molecules must be present in the entire chain and during the entire course of the reactions of formation of CO ₂ .

g) The relaxation time of the vibrational energy of the molecule N ₂ and (or) CO must be at least the flight time of the gas mixture of the induction zone and the reaction zone.

 This natural requirement requires that throughout the induction zone and the reaction zone, CO molecules be fed vibrational energy from nitrogen molecules.

 The implementation of the method.

If all of the above requirements are fulfilled, the conditions are created when the vibrational energy of the newly formed CO ₂ molecules is transferred to nitrogen molecules and is "frozen" in it for some time. Further, this vibrational energy is transferred to CO molecules, transferring them to an excited state. For vibrationally excited CO molecules, due to the presence of vibrational temperature in the exponential factor of the reaction rate coefficient, the number of CO ₂ molecules increases sharply. This, in turn, leads to an increase in the stored vibrational energy of gases and an increase in the "pumping" of CO molecules. There is an avalanche-like process of increasing the reaction rate and the burnout of this type of fuel is carried out in an explosive way.

The aim of the invention is the device gas-dynamic CO ₂ laser for implementing the method of creating an inverse population are:
- a significant improvement in the characteristics of the active medium of the laser and an increase in the specific energy consumption per unit gas flow rate;
- reducing the initial temperature of the mixing gases, reducing the gas pressure in the receiver and energy costs for gas compression;
- increasing the height of the critical section of the nozzles to 1 - 1.2 mm, eliminating the vibration of the nozzle blades and increasing their service life;
- a significant reduction in the divergence of laser radiation, by reducing the effect of vibration of the mirrors of the optical resonator on it;
- creation of a cost-effective technological laser in operation, including for an autonomous transported option.

 The goal is achieved by the designs of nodes and circuit solutions of the device shown in FIG. 14.

The device of a gas-dynamic CO ₂ laser (GDL) includes: combustion chambers as generators of the mixture of components of the heated gas 1; a receiver necessary for uniform supply of a mixture of gases in the nozzle block 2; a supersonic nozzle block 3 recruited from flat nozzle blades 4; an injection device for supplying the second of the components of the cold gas (a mixture of oxidizer gases with nitrogen or fuel), placed in the subsonic part of the nozzle block 5; the flow part of the resonator 6; optical resonator 7; supersonic and subsonic laser diffusers 8; a gasdynamic window for outputting laser radiation from the resonator 9; turbocharger for supplying compressed air 10; exhaust system with an ejector 11; cooling systems of units and assemblies of the device.

 The operation of the laser complex is as follows: the incoming atmospheric air 12 is compressed in a turbocompressor and then the high pressure air 13 is first supplied between the walls of the receiver 2, regenerating the heat released in the combustion chambers 1, then directly into the combustion chambers 1, as well as into the injection unit 5 through the manifold 14. Low pressure air 15 from the turbocharger 10 enters the gasdynamic window 9 and to cool the laser assemblies 16. Combustion chambers 1 are located on the side and end surfaces of the Iver 2, which provides uniform distribution of the gas parameters at the inlet of the nozzle block, the minimum gas dynamic and heat losses.

The hot component of the gases 17 coming from the combustion chambers 1 is fed into the receiver 2 to the input of the nozzle block 3, mixed with the cold component coming in through the injector device 5, and a combustion zone of CO is created in the vicinity of the critical section of the nozzles 18. Moreover, depending on the parameters the gas flows of the hot and cold components of the hole of the injection unit 5 are placed at an optimal distance (L _opt ) from the critical nozzle section, determined from the relation: L _opt = ud ² / D _t , where u is the velocity of the gas mixture in the subsonic part of the nozzle, d - hara characteristic size of the injection device, D _t - turbulent diffusivity. This condition means that the mixing of the turbulent moles of the gas component should be completed in the region of the critical section of the nozzles 18.

The nozzle vanes 4 have central channels for cooling with water 19, which are joined with the supply 20 and drain 21 pipelines, and in the subsonic part the channels 5 with the injector openings for supplying a cold gas component to the main gas stream. In addition, in the region of the critical cross section of the nozzles 18, the requirements must be satisfied that the mixing time of the gases at the monomolecular level τ _{cm is} no more than the time of chemical reactions between the molecules of the reacting gases τ _chemical , i.e. τ _cm <τ _chemical . The mixing time at the monomolecular level can be determined τ _cm ~ L ² / D _m , where L is the thermal scale of the gas flow turbulence, and D _M is the molecular diffusion coefficient. The thermal scale of turbulence according to the theory of A.N. Kolmogorov can be estimated from the formula L ~ h / Re ^3/4 , where h is the characteristic size of the height and width of the platform of the constant critical section of the nozzles 18, and Re is the Reynolds number determined by the characteristic size h and parameters of the gas flow. Then the condition for choosing the characteristic size h is defined as follows: h <τ $\genfrac{}{}{0ex}{}{\text{2}}{\text{chem}}$ (u / ν) ³ D $\genfrac{}{}{0ex}{}{\text{2}}{\text{m}}$ , where u is the gas velocity, and ν is the kinematic viscosity of the gas.

 The receiver 2 is made in the form of a segment of a thin-walled pipe with double walls and, with the help of flanges, joins the flanges of the nozzle block body 22. Such a design in operating mode under gas pressure inside allows improving sealing between the nozzle block body 22 and nozzle blades 4, and, in addition stretching them reduces the vibration of the shoulder blades.

The optical resonator is made of 4-pass, 6-mirror with two angular reflectors 23, 24, providing a flip of the radiation beam along the gas flow in the resonator flow zone at each radiation pass between the mirrors. At the same time, on one side of the gas flow of the active medium there is a large angular reflector 23, and on the other side of the medium there is a block of mirrors, including a small angular reflector 24, an output convex 25 and a rear concave 26 mirror, in addition, the edges of the corner reflectors are placed perpendicular to each other. The output radiation spot has the shape of a rectangle with a cut out corner. This optical resonator circuit has the following advantages over others:
- flipping the radiation beam allows you to get the distribution of the radiation intensity in the output beam close to uniform;
- reduce the influence of the active medium on the divergence of radiation;
- significantly reduces the sensitivity of the resonator to the alignment of the mirrors under the action of dynamic and acoustic loads during operation of the gas-dynamic path of the laser and the turbocharger, and therefore reduce the integral divergence of radiation.

 The diffuser, designed to inhibit gas and restore static pressure 8, consists of a supersonic part, which includes a narrowing channel, providing a smooth transition from a rectangular section to a round 27 and a pipe of constant cross section 28, and a subsonic part from a truncated expanding cone 29 and a pipe of constant cross section 30. In this case, the pipes of the final subsonic part of the diffuser 30 are an integral part of the ejector 11 of the exhaust device.

 The laser device is equipped with an ejector 11, in which the exhaust gases 31 from the turbocharger 10 are used to eject the exhaust gases from the gas-dynamic path of the laser directly 32. This allows you to create additional vacuum at the output of the laser diffuser and reduce the required gas pressure in the receiver 2, necessary to start the diffuser, which , in turn, reduces the requirements for a turbocharger and reduces the cost of operation of the complex. A noise suppressing device 33 is installed at the ejector exhaust to reduce the acoustic effects of the exhaust gas stream 34 on equipment and maintenance personnel.

 Fuel for the turbocharger 10 and gas generators 1 is supplied by pump 35 from the tank 36 through a piping system 37, first to a heat exchanger 38, in which the refrigerant pumped through pump 39 through the cooling system 40 of the mirrors of the optical resonator 7 transfers heat to this fuel. In addition, the laser device uses an electric generator 41, driven in rotation from the shaft of the turbocharger. This technical solution allows you to create a technological laser completely autonomous from external cooling and power systems.

Using the method and device for its implementation will improve the following characteristics of a gas-dynamic CO ₂ laser:
- significantly increase the gain and the stored vibrational energy of the active medium, the resonator efficiency and the output radiation power of not less than two times in comparison with the equilibrium mode of the GDF;
- reduce the initial temperature of the mixing gases to 1000 K or less;
- increase the height of the critical section of the nozzles, increase the thickness of the nozzle blades, remove the problems of cooling them and significantly increase the service life;
- to obtain the minimum divergence of radiation (not more than 1.5 mrad in energy level 0.9) at high power;
- create a cost-effective technological CO ₂ laser of high power.

Example 1. This method of creating an inverse population was tested on a model gas-dynamic installation, which included a solid fuel gas generator, a receiver, a single slotted nozzle, a cold air supply system through a series of injector openings in the subsonic part of the nozzle, a vacuum container, and a measurement system gain factor. The height of the critical section of the nozzle was 0.3 mm, the degree of opening of the supersonic part was 40, and the gas pressure in the receiver varied in the range 30–50 at. The composition of the combustion products at the outlet of the gas generator included CO, H ₂ , N ₂ and when it was burned in air (in the gas generator) in the usual equilibrium GDL mode at a temperature of 1800 K, the gain of the active medium was 0.3 - 0.5 1 / m and the stored vibrational energy is up to 16 kJ / kg. In the case of a nonequilibrium regime of afterburning the mixture in air in the region of the nozzle critical section at a temperature of 1000 K and lower, the gain of the active medium had a maximum value of 1 1 / m, and the stored vibrational energy increased to 25 kJ / kg. In this case, the rate of relaxation of vibrational energy along the flow of the active medium was significantly lower than for the equilibrium GDL regime.

Example 2. We tested a device CO ₂ - GDL, including a combustion chamber operating on the products of combustion of kerosene in air, a receiver, a nozzle block drawn from flat nozzle blades, a cold air injector representing a comb of thin tubes with holes, which had the ability linear displacement relative to the critical section of nozzle blades, the flow passage of the resonator, stable and unstable optical resonators, a diffuser, an exhaust system, and a turbocompresso as a source of compressed air R. The height of the critical section of the nozzles was 0.5 mm, the degree of opening of the supersonic part of the nozzle was 30, the pressure of the gases in the receiver was 3–5 atm, and for the nonequilibrium GDL regime in the combustion chamber, kerosene in the air was burned with a deficiency of oxidizer in such a way that a certain amount was produced CO, which was burned in the vicinity of the critical section of the nozzles by blowing cold air into the injector. For the equilibrium GDL regime, complete combustion of the fuel was carried out in the combustion chamber, but air was not blown into the injector. The experimental results showed that, if for the equilibrium GDL regime at a temperature of combustion products of 1700 K the typical maximum gain of the active medium was 0.4 - 0.5 1 / m, the stored vibrational energy was 12 kJ / kg, and the output radiation power from the unstable resonator 4 5 kJ / kg, then for the nonequilibrium GDL regime and the temperature of suitable gases less than 1000 K, the corresponding values of the gain, stored vibrational energy, and output power were 0.81 1 / m, 23 kJ / kg and 8 kJ / kg. In this case, the nonequilibrium GDL regime was obtained only with certain parameters of the mixing gases and a given optimal position of the injector comb relative to the critical nozzle section. In addition, in the nonequilibrium GDL regime, the effect of complete burnout in the vicinity of the critical section of the soot nozzles was observed, which was formed in the combustion chamber when kerosene was burned with an oxidizer deficiency in them.

 Example 3. The GDL model installation was tested by the authors of [8], which included: a plasma torch for heating air, a receiver, a nozzle block drawn from flat blades, an injector from a tube comb installed in front of the nozzle block and having the possibility of linear movement relative to it, exhaust tank and component feed systems. Air was heated by a plasma torch to 1000 - 1100 K, and propane gas was injected into the injector; the nozzle critical section height was 1.2 mm, the supersonic part of the nozzle was disclosed at 25, and the gas pressure in the receiver was 9 atm. Measurements of the gain showed that if for the equilibrium GDF regime and a gas temperature of 1600 K it did not exceed 0.5 1 / m, then for a nonequilibrium mode with an optimal injector position relative to the critical nozzle cross-section and a gas temperature of 1000 K, its value reached 0.7 1 / m

The above examples experimentally substantiate and confirm a new method of inverting the active medium in a gas-dynamic CO ₂ laser at a low temperature of gases in a wide range of parameters and a significant improvement in the technical characteristics of a device that implements this method.

Sources of information
1. Anderson J. "Gas-dynamic lasers: an introduction.""World", 1979, p. 13-42.

 2. French patent N 604514, cl. H 01 S 3/0953, 1978.

 3. RF patent N 2059333, cl. H 01 S 3/0953, 1996.

 4. Ablekov V. K. and others. "Guide to gas-dynamic lasers" - M.: "Engineering", 1982, p. 19, 20.

 5. RF patent N 2065240, cl. H 01 S 3/0979, 1996.

 6. RF patent N 2029421, cl. H 01 S 3/08, 1995.

 7. Ablekov V. K. and others. "Guide to gas-dynamic lasers" - M .: "Engineering", 1982, p. 12.

 8. Zaklyazminsky L.A. and others. "The effect of propane on the gain in a supersonic flow", FGV N 6, 1980.

Claims (8)

1. The method of creating an inverse population in a gas-dynamic CO ₂ laser, characterized in that it involves the use of oxidation of carbon monoxide (CO) in the presence of an oxygen-containing oxidizing agent, nitrogen (N ₂ ), hydrogen (H ₂ ) or water vapor (H ₂ O), pre-heating one of the components of the fuel mixed with N ₂ , H ₂ (H ₂ O) or an oxidizing agent mixed with N ₂ , H ₂ (H ₂ O) or obtaining heated components by burning hydrocarbon or solid fuels, followed by mixing all gas components and creating a combustion zone in the critical about the cross section of the supersonic nozzle, while organizing the jet mixing of the components in the subsonic part of the nozzle so that complete mixing of the gases at the monomolecular level occurs in the region of the critical section of the nozzle, and the parameters of the mixing gases are selected and maintained during the course of reactions in a given range, based on conditions so that in the mixing zone of the components at the monomolecular level in the region of the critical section of the nozzle the following conditions are satisfied: the mixing time of the components at the monomolecular level there was no more time for chemical reactions between the molecules of the reacting components; the time of the chemical reactions of the formation of the CO ₂ molecule was no more than the relaxation time of the vibrational energy of the CO ₂ molecule; the time of transfer of vibrational energy from the lower vibrational level 001 of the CO ₂ molecule to the lower vibrational level of the N ₂ molecule should be no more than the relaxation time of the vibrational energy of the CO ₂ molecule; the relaxation time of the vibrational energy of the molecule N ₂ and (or) WITH must be not less than the relaxation time of the vibrational energy of the molecule CO ₂ ; the time of transfer of vibrational energy from the lower vibrational level of the molecule and N ₂ and (or) from the CO ₂ molecule to the lower vibrational level of the CO molecule should be no more than the relaxation time of the vibrational energy of the N ₂ and CO molecules; the relaxation time of the vibrational energy of the CO molecule must be at least the time of the entire chain of chemical reactions of the formation of the CO ₂ molecule; the relaxation time of the vibrational energy of the molecule N ₂ and (or) WITH must be at least the flight time of the gas mixture of the induction zone and the reaction zone. 2. Apparatus for carrying out the population inversion in the gas-dynamic CO ₂ laser at low temperature, comprising a tank for storing raw component working gas mixture or Fuels; compressors and component feed pumps; heating device or fuel combustion chambers; receiver; a nozzle block recruited from flat nozzle vanes; flow part of the resonator; optical resonator; diffuser; exhaust system; cooling system compressor; refrigerant storage capacity; heat exchanger; gasdynamic window for outputting laser radiation from the resonator, characterized in that the holes of the injection unit of the combustion chamber installed in front of the nozzle block through which the cold component of gas is injected are placed at an optimal distance (L _opt ) from the critical section of the nozzles, determined from the relation L _opt = ud ² / D _t , where u is the velocity of the gas mixture in the subsonic part of the nozzle; d is the characteristic size of the injection device; D _t is the coefficient of turbulent diffusion; the height and platform of the constant critical section of the nozzles (h) must satisfy the relation: h <τ $\genfrac{}{}{0ex}{}{\text{2}}{\text{xim}}$ (u / ν) ³ D $\genfrac{}{}{0ex}{}{\text{2}}{\text{M}}$ where τ _xim is the chemical reaction rate of the reacting gases; u is the velocity of the gas mixture in the region of the critical section of the nozzle; ν is the kinematic viscosity of the gas mixture; D _M is the molecular diffusion coefficient of miscible gases.  3. The device according to claim 2, characterized in that the receiver is made in the form of a pipe segment with double walls, between which one of the components of the cold gas passes and it is joined by flanges to the nozzle block body; gas generators of the hot component are placed in the receiver along the side or end surfaces of the pipe.  4. The device according to claim 2 or 3, characterized in that the nozzle vanes have central channels for cooling with water, which are joined to the supply and drain pipelines, and in the subsonic part there are channels with injector holes for supplying a cold gas component to the main gas stream.  5. The device according to p. 2, or 3, or 4, characterized in that the optical resonator is made of 4-pass, 6-mirror with two angular reflectors, providing a revolution of the radiation beam through the gas stream in the flow zone of the resonator at each radiation pass between the mirrors so that on one side of the gas flow of the active medium there is a large angular reflector, and on the other side of the medium a block of mirrors, including a small angular reflector, an output convex and rear concave mirrors, while the edges of the corner reflectors are sized scheny perpendicular to each other.  6. The device according to p. 2, or 3, or 4, or 5, characterized in that the high and low pressure air, respectively, is supplied to the combustion chambers, an injection device for blowing in front of the nozzle block, as well as in a gas-dynamic window and for cooling laser nodes.  7. The device according to claim 2, or 3, or 4, or 5, or 6, characterized in that the cooling system of the mirrors of the optical resonator is equipped with a heat exchanger through which fuel is pumped into the turbocharger, the laser combustion chamber and removes heat absorbed in in the mirrors.  8. The device according to claim 2, or 3, or 4, or 5, or 6, or 7, characterized in that the exhaust system of the device is equipped with an ejector, in which the exhaust gases of the turbocompressor are used to eject the laser exhaust gases, as well as a noise suppressing unit, in this case, the subsonic final part of the laser diffuser is made in the form of tubes of constant cross section, which, in turn, are an integral part of the ejector.

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