RU2743777C1 - Bladeless microturbine engine - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates mainly to turbine engineering, namely to gas turbine engines of small dimensions (microturbine engines), which can be used as a drive for an electric generator in hybrid vehicles, in small unmanned aerial vehicles, as well as in autonomous electric generators. In a microturbine engine containing a fixed housing 1, 19, a compressor wheel 6, a heat exchanger 7, a combustion chamber 8 and 9 with a fuel injector 15 and a glow plug 17, a nozzle device 10, 11 and an outlet pipe 18, a screw mounted on bearings is used as a rotor 2 with a multi-start external thread, which is located with a gap relative to the housing 1, 19, provided with grooves on its inner cylindrical surface.

EFFECT: said invention is aimed at simplifying the design and manufacturing technology of a microturbine engine, as well as increasing its efficiency.

4 cl, 3 dwg

Description

The invention relates to mechanical engineering, mainly to turbine engineering, namely to gas turbine engines of small dimensions (microturbine engines), which can be used as a drive for an electric generator in hybrid vehicles, in unmanned aerial vehicles of small dimensions, as well as in autonomous electric generators.

Gas turbine engines (GTE) are the most widely used in aviation. Attempts to use small-sized gas turbine engines in land vehicles were made in the early fifties of the last century. The first car with a gas turbine engine in the world is considered to be the Rover JET1 of the Rover Car Co. Ltd. And in 1954, General Motors (GM) introduced the Firebird XP-21. At that time, the companies Boeing, Ford, Chrysler were also involved in the development of vehicles on the gas turbine engine. These were, in the main, one-off examples of racing cars, the economic aspect for which was not significant for the developers. It should be noted that through joint efforts these companies managed to solve most of the inborn problems of the gas turbine engine. For example, in the mid-sixties, Chrysler designed and manufactured the Chrysler Turbine gas turbine sedan. The fuel consumption of these cars was 11.7 liters per 100 km, the maximum speed is 180 km / h, acceleration to 100 km / h in 8 seconds. 50, almost ready for serial production of cars, the company handed out for a long test. The tests were successful, but all companies, including Chrysler, gradually curtailed developments in this direction. It is possible that the auto giants did not want to rebuild the long-established system for the production of piston cars and make large investments in organizing the mass production of vehicles using gas turbine engines.

Subsequently, the development of the automotive industry led to the creation of hybrid vehicles. This gave a second chance to use the GTE. In hybrid cars, there is no mechanical connection between the engine and the wheels, which makes such shortcomings of small-sized GTEs as high rated turbine speed, low sensitivity to control (response to "gas"), and lack of engine braking mode insignificant.

In 1998, the American company Capstone Turbine Corporation (Capstone) sold the first small-sized gas turbine power plant, which was named "Microturbine". Currently, more than 9,000 Capstone microturbine units are in operation in 73 countries around the world for autonomous power generation. The use of microturbines as a drive for an electric generator for hybrid vehicles is promising. Capstone presented the SMT-380 hybrid electric sports car, and in 2009, together with the British firm Landford, on the basis of the seven-seat Ford S-Max crossover, a sequential Eco-Logic hybrid was developed using C30 microturbines. Demonstration tests of this hybrid were carried out, but the serial production did not begin. The C30 microturbine is installed in eco-friendly hybrid buses that run along the Newcastle waterfront. In Russia, the Trolza company in 2009 developed and successfully tested the Trolza-5250 hybrid bus, which was named Ecobus, based on the C65 microturbine. Several copies of Ecobus were made, but it did not go into production. Despite the environmental appeal, cars and buses based on Capstone microturbines have not been widely used. Most likely this is due to the fact that even with a well-established serial production, the cost of their microturbines is very high. In addition, due to the design of the air bearing, the number of starts of the Capstone microturbines is severely limited, which is undesirable in the start-stop mode of a hybrid vehicle.

In Russia, the development and production of power plants and multifunctional power units based on microturbine engines is carried out by JSC SKB "Turbina". Since 1970, the serial production of the GTA-18A gas turbine unit, intended for an auxiliary power plant, which provides power to the systems of the T-80U tank, began. At present, in particular, a power unit for the oil APN-18 and a small-sized turbojet engine TD30 are being produced. The APN-18 unit with a power of 18 kW has an electrical efficiency (COP) of 14% and a weight of about 1000 kg. The TD30 turbojet engine is designed for light unmanned aerial vehicles as a propulsion engine for generating thrust and providing an on-board network. The output electric power of TD30 is 1100 W, the time of continuous operation is 2 hours. There is no data on the use of microturbine engines of this joint stock company for hybrid vehicles.

Both Russian and foreign microturbine engines are overwhelmingly vane. A systemic disadvantage of blade turbines is the limitation of the maximum operating gas temperature and, accordingly, the efficiency, which depend on the thermal stability and strength of the blades at the corresponding circumferential speeds of the rotor. In addition, blade turbines have large losses of the working fluid through leaks in the gas joints, which is especially true when the diameter of the turbine rotor is small. To increase the heat resistance and strength of the turbine blades, expensive alloys with the use of rare earth metals are used, which leads to a complication of technology and an increase in the cost of microturbine engines even during their serial production.

The aim of the present invention is to simplify the design and manufacturing technology of microturbine engines, which will improve their reliability and service life. This will reduce manufacturing and operating costs. In contrast to vane microturbine engines, all other things being equal, the design features of the helical rotor of the proposed microturbine engine make it possible to withstand higher speeds with an increase in the maximum operating gas temperature, which makes it possible to obtain a higher efficiency.

In accordance with the invention, the technical result is achieved in that a bladeless microturbine engine containing a fixed housing, a compressor wheel mounted on the rotor shaft, a heat exchanger, a combustion chamber with a fuel injector and a spark plug, a nozzle device and an outlet pipe. The rotor of the microturbine engine is made in the form of a screw mounted on bearings with a multi-start external thread, which is located with a gap relative to the stationary body, provided with grooves on its inner cylindrical surface. In the body, either annular grooves, the depth of which increases in the direction of the outlet pipe, or grooves in the form of a multi-start internal thread, the direction of which is opposite to the direction of the external multi-start thread of the screw, can be made. Thanks to these grooves in the gap between the screw (rotor) and the stationary body, under the action of the moving heated gas, the process of turbulent friction is intensified and, in comparison with a smooth bushing, the amount of energy transferred from the heated gas to the rotor significantly increases. Moreover, the effect of energy transfer, and, accordingly, the rotor speed, increases nonlinearly with an increase in the gas temperature in the combustion chamber and the pressure at the gas inlet into the gap. The increase in the size of the annular grooves of the housing in the direction of the outlet pipe allows for the continued expansion of the heated working gas, which additionally increases the energy transfer coefficient to the rotor.

Figure 1 shows a longitudinal section of a microturbine engine in the design with annular grooves on the inner cylindrical surface of the housing. Figure 2 shows a longitudinal section of a microturbine engine in the design with a multi-threaded internal thread on the housing. Figure 3 shows a section A - A along the parting line.

The microturbine engine (Fig. 1) contains a housing 1, a multi-threaded screw 2 mounted on a shaft 3, a bearing assembly 4, an air filter 5, a compressor wheel 6, which is designed to pump air into the converging channels 7. These channels function as a heat exchanger and diffuser. The cleaned and compressed air is supplied to the combustion chambers 8 and 9 having nozzle devices 10 and 11 (figure 3). To balance the pressure in the combustion chambers, an annular groove 12 is made in the body. The cover 13 (figure 1) is sealed with a metal gasket 14. On the body 1, nozzles 15 and 16 are installed, and on the cover a glow plug 17. On the inner cylindrical surface of the body 1 there are circular grooves depth which increases towards the outlet 18. On the inner cylindrical surface of the housing 19 (figure 2), grooves are made in the form of a multi-start internal thread, the direction of which is opposite to the direction of the external multi-start thread of the screw (if the screw has a left thread, then it has a right thread on the housing).

The grooves on the surfaces of the propeller and the housing of the microturbine engine can have various shapes, for example, trapezoidal, rectangular, triangular. However, in accordance with claim 4 of the formula, the preferred shape of the grooves in the form of semicircles with a radius equal to the depth of the grooves.

The microturbine engine works as follows. When starting, the motor-generator (or compressed air) drives the shaft 3. The compressor wheel through the air filter 5 supplies compressed air through the channels 7 of the heat exchanger to the combustion chambers 8 and 9. Then, liquid fuel is injected into these chambers or compressed gas is supplied. The formed fuel-air mixture is ignited from the glow plug 17. The fuel is ignited and the gases heated to the operating temperature are directed through the nozzles 10 and 11 into the gap between the screw and the housing, where they expand and perform work on the rotation of the screw (rotor). The microturbine engine is started and the motor-generator goes into the generation mode, and the glow plug is turned off, since the ignition of the fuel-air mixture occurs spontaneously from contact with the heated surfaces of the combustion chambers. The rotor speed is regulated by changing the fuel supply. When using a microturbine engine in hybrid vehicles, the rotor speed can be chosen constant, optimal for stable engine operation and charging batteries from the generator.

Claims (4)

1. A bladeless microturbine engine containing a fixed housing, a compressor wheel mounted on the rotor shaft, a heat exchanger, a combustion chamber with a fuel injector and a glow plug, a nozzle device and an outlet pipe, characterized in that a screw mounted on bearings with a multi-threaded external thread is used as a rotor , which is located with a gap relative to the body, provided with grooves on its inner cylindrical surface. 2. A bladeless microturbine engine according to claim 1, characterized in that annular grooves are made on the inner cylindrical surface of the housing, the depth of which increases in the direction of the outlet pipe. 3. A bladeless microturbine engine according to claim 1, characterized in that grooves are made on the inner cylindrical surface of the body in the form of a multi-start internal thread, the direction of which is opposite to the direction of the external multi-start screw thread. 4. A bladeless microturbine engine according to claim 1, characterized in that the profiles of the grooves of the screw and the housing in the normal section have the shape of semicircles with a radius equal to the depth of the grooves.

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