Burner

 

(57) Abstract:

Usage: in the energy, transport and chemical engineering, in particular in azotobacteria. The inventive burner containing axial vane swirler air blades and sleeve and the adjacent annular chamber formed by the said sleeve and cylindrical sides, narrowing device installed at the outlet of the cylindrical shell, made in the form of conical-like, sleeve swirl running through it, beyond the ring prelimary, and the length of the ring prelimary is a function of the height of the blades and the angle of swirl flow in the swirl. 2 C.p. f-crystals, 4 Il.

The invention relates to energy, transport and chemical engineering and can be used in combustion chambers of gas turbine installations.

Known burner containing toplivopodayuschie device, axial vane swirler air blades and sleeve and the adjacent annular chamber formed in the said sleeve and a cylindrical shell located coaxially with it and covering the vanes of the swirler, and a narrowing ustroyu axial vane swirler and the output of the ring prelimary. (See Turbomachinery Technology Seminar, Gas Turbine Combustion System Technology. Caterpillar. Solar Turbines TTS 52/492 1992, p. 52 2, Figure 2). Annular prechamber here is intended to implement the process of mixing fuel with air and get a lean homogeneous air-fuel mixture, with subsequent burning outside prelimary. This method of burning fuel can significantly reduce emissions of harmful substances in the combustion products, in particular, oxides of nitrogen.

However, during operation of the burner on certain modes, the phenomenon of overshoot of the flame, i.e. the combustion of fuel inside prelimary. The leakage cannot be tolerated, because it is several times higher emissions of oxides of nitrogen.

Known burner containing toplivopodayuschie device, axial vane swirler air blades and sleeve and the adjacent annular chamber formed in the said sleeve and a cylindrical shell located coaxially with it and covering the vanes of the swirl, as well as a narrowing device installed at the outlet of the cylindrical shell and is made in the form of a flat chart, which is located with a gap to the end surface of the sleeve swirl. (See Development of Dry Low-NOx

However described, the burner has a number of disadvantages. First, inside prelimary near the aperture (in the corner at the junction of the aperture with a cylindrical shell) has a stagnant zone of low velocity air-fuel mixture. With the outer side of the diaphragm, due to separation of flow is constantly maintained toroidal vortex, i.e., there is a zone of reverse currents, which contribute to the stabilization of the flame near the diaphragm. Under certain conditions, the joint occurrence of these two processes leads to the so-called "thermal" breakthrough flame, when due to the stabilization of the flame on the outer surface of the diaphragm it is heated to a temperature exceeding the ignition temperature of the fuel-air mixture inside prelimary and mix lights up. When ignited air-fuel mixture stagnant zone will be constantly supporting combustion in the prechamber. On the inadmissibility of breakthrough flame in the chamber mentioned above.

Second, aperture directs the swirling stream of air-fuel mixture from prelimary along the conical end surface of the bushing dependence which in turn reduces the resistance of the torch. Given that burners with premixing fuel with air have a more narrow range of stability of the flame in comparison with the diffusion burners, this lack of consideration of the burner is essential.

The third drawback of the considered burner is that toplivopodayuschie device is located within the swirler (in the direction of air flow). To ensure the homogeneity of the air-fuel mixture at the outlet of prelimary and reduce the length of prelimary you need to distribute the fuel using toplivovozdushnoy device cross-section prelimary proportional to the air flow. In other words, when the distribution of fuel it is necessary to consider the radial velocity profile of the air in the section toplivovozdushnoy device. In the immediate vicinity for the radial swirl profile air speed has a complex shape which is dependent on many parameters. Currently, there are no generalized dependence, to describe the velocity distribution of the air near the swirl. Therefore, the optimal distribution of the fuel swirler requires long-term experimental treatment in each case. In addition, topl is formed aerodynamic traces of area treated currents, which can stabilize the flame in the event of leakage of the flame in the chamber. Even if a breakthrough does not occur, because of the presence of aerodynamic traces, to align the field concentration of the air-fuel mixture is required, the chamber of great length.

The problem to which the invention is directed, is to create a new design of the burner to reduce the toxicity of products of combustion and to increase the stability of the operation of the burner and its reliability.

The technical result that can be achieved with the implementation of the claimed invention is the provision of toxicity of the exhaust gas turbine units within existing standards.

The problem is solved by the fact that in the known burner containing toplivopodayuschie device, axial vane swirler air blades and sleeve and the adjacent annular chamber formed in the said sleeve and a cylindrical shell located coaxially with it and covering the vanes of the swirl, as well as a narrowing device installed at the outlet of the cylindrical shell, according to the present invention narrowing device is designed as a conical per the n option, when axial vane swirler is mounted between topleveladmin device and the output of the ring prelimary, the length of the ring prelimary is determined by the following formula:

l = khcos,

where k is an empirical coefficient ( K 2,3-2,9);

h the height of the vanes of the swirler;

v angle of swirl flow in the swirl.

Another option is, when the speaker outside prelimary end of the sleeve swirl is made with a perforated end wall, and inside the sleeve there is adjacent to the wall of the cavity is provided with a channel whose inlet is located in front of the swirl of air.

The essence of the claimed invention is that by doing orifice in the form of a conical-like inside prelimary there are no stagnant zones of low velocity air-fuel mixture, which can stabilize the combustion in the event of leakage of flame, and the like well-cooled high-speed flow of air-fuel mixture, and the temperature is always below the temperature of ignition of the mixture. In the outside like there is no clear toroidal vortex, as is the case in the prototype, and the flame is stabilized only in the cooperation is essential in the prototype, and thermal breakthrough is missing.

Because of the cylindrical sleeve swirl passes through the conical-like, speaking outside prelimary, annular swirling jet fuel-air mixture exits prelimary in the axial direction, and not at an angle to the axis, as in the prototype. When this area of the reverse currents near the axis has a considerably large volume and length, which has a positive impact on the sustainability of the torch and extends the range of operating conditions of the burner.

Location toplivovozdushnoy device in front of the vane swirler air allows to distribute the fuel in accordance with the air distribution in this section, because the velocity profile of the air before swirler fairly uniform. As a result, the output from prelimary achieves a more uniform field concentrations of air-fuel mixture and, accordingly, reduces the emission of nitrogen oxides. Location toplivovozdushnoy device before swirler air also allows you to shorten the length of prelimary (compared to the prototype) at a constant emission of oxides of nitrogen.

When the location toplivovozdushnoy device prior to swirl in the chamber of a no Aero is output from prelimary more uniform, on the other hand, no traces reduces the likelihood of leakage of the flame in the chamber.

Research natural burner, held at the shooting stand, showed that when installing toplivovozdushnoy device before the swirl of prelimary can be quite short and its length is determined from the relation (1). When the length of prelimary less than follows from the formula (1), the efficiency of mixing in the chamber is reduced and the emission of nitrogen oxides increases dramatically. To make the chamber of greater length is impractical, because the emission of nitrogen oxides remaining virtually unchanged, and the dimensions of the burner and, therefore, combustion chamber, are growing.

Unlike the prototype, where the tapered end surface of the sleeve swirl cooled washing its swirling stream of air-fuel mixture in the inventive burner sleeve swirl is beyond prelimary and is the stabilizer of the torch, which improves the stability of operation of the burner. However, for reliable operation of the burner it is necessary to cool the end surface of the sleeve swirl, because it is in direct contact with hot combustion products. For cooling and reliability R is euda channels for air flow through the perforations, communicated with an air space in front of the swirl of air. Due to the pressure difference on the swirl and the chamber, the air flows through the channels in the sleeve and through the perforation to the end surface of the sleeve swirl, lowering its temperature.

In Fig. 1 shows a longitudinal section of the burner; Fig. 2 is a section of the burner directly behind topleveladmin device of Fig. 3 and 4 show a variant of the construction execution toplivovozdushnoy device.

Burner contains toplivopodayuschie device 1, the axial vane swirler 2 air blades 3 and the sleeve 4 and the adjacent annular chamber 5 formed in the said sleeve 4 and the cylindrical shell 6, which is located coaxially with it and covering blades 3 of the swirler 2, as well as a narrowing device made in the form of a conical-like 7 and installed at the outlet of the cylindrical shell 6 (Fig. 1). Moreover, the sleeve 4 swirl 2 passes through a conical-like 7 and extends beyond the ring prelimary 5. Facing the end of the sleeve 4 swirl 2 is made with a perforated end wall 8.

Inside the said sleeve 4 has a cavity 9, adjacent to the perforated her face is ptx2">

Axial vane swirler 2 installed between topleveladmin device 1 and the output of the ring prelimary 5, the length of prelimary 5 is determined by the following formula:

l = khcos,

where k is an empirical coefficient (k2,3-2,9);

h the height of the vanes of the swirler;

v the angle of twist in the swirl.

It should be noted that toplivopodayuschie device 1 may have a different design options. So, in Fig. 1 and Fig. 2 depicts toplivopodayuschie device 1 in the form of perforated radial pipe 11, as is done in the prototype and similar. In Fig. 3 and 4, for example, presents toplivopodayuschie device 1 in the form of three communicated with each other an annular reservoir 12. There are other possible designs.

During burner operation air is supplied to the input shell 5 (see arrow in Fig. 1). To eliminate flow separation and the formation of a uniform velocity profile input section of the shell 5 is a smooth rounded confuser. Next, the air stream flows on toplivopodayuschie device 1, through openings 11 in which the flows of the fuel gas. The diameter and pitch of the holes 11 may be selected, for example, so that the fuel consumption is proportional to kV is each other. Then the fuel-air mixture passes through the blades 3 of the swirler 2 air enters the chamber 5 in the form of an annular swirling jet. When the swirling motion of the jet in the chamber 5 under the action of mass forces due to the intensive turbulent transport is efficient mixing of fuel with air, and at the exit of prelimary 5, the length of which is determined from the aforementioned formula, the air-fuel stream has a fairly uniform field concentrations, and therefore low emissions of nitrogen oxides during the subsequent combustion of the mixture. Passing through the conical-like 7, the air-fuel flow smoothly accelerated by purchasing in the outlet section pinches the maximum speed for all modes of operation of the burner exceeds the speed of flame propagation, thanks excluded breakthrough flame in the chamber. When the flow in the chamber 5 there is no tear and stagnant zones, which can stabilize the flame in the short-term overshoot of the flame in the chamber of a (non-nominal modes). The inner surface pinches 7 is washed by the high-speed swirling cold air-fuel mixture, thus achieving efficient cooling pinches 7 and excludes the t movement in the axial direction along the sleeve 4 of the swirler 2, forming at its end wall 8 of the developed area of the reverse currents, which provides good stabilization of the flame in a wide range of modes of operation of the burner.

To ensure the reliability and duration of the resource of the burner end wall 8 of the sleeve 4 of the swirler 5 performed cooled. Part of the air space in front of the swirl channels 10 through the perforation holes in the wall 8 is fed into the firing space, creating near her protective veil. The cooling air is relatively small and does not affect the combustion of the fuel-air mixture.

As can be seen from the figures and descriptions of the inventive burner contains commonly used in these devices, elements: cylindrical and conical shells, pipes, vane swirler. Therefore, its implementation does not cause any technical problems.

1. Burner containing toplivopodayuschie device, axial vane swirler air blades and sleeve and the adjacent annular chamber formed in the said sleeve and a cylindrical shell located coaxially with it and covering the vanes of the swirl, as well as a narrowing device installed at the outlet of cylindrically passes through it, outside the ring prelimary, and the length of the latter is a function of the height of the blades and the angle of rotation of the swirl flow.

2. Burner under item 1, characterized in that the axial vane swirler is mounted between topleveladmin device and the output of the ring prelimary, while the functional dependence of the length of the ring prelimary of the height of the blades and the angle of twist of the thread is determined by the following formula:

l = khcos,

where k is an empirical coefficient (k 2,3 2,9);

h the height of the vanes of the swirler;

- the angle of swirl flow in the swirl.

3. Burner under item 1, characterized in that the protruding beyond prelimary end of the sleeve swirl is made with a perforated end wall, and inside the sleeve there is adjacent to the wall of the cavity is provided with a channel whose inlet is located in front of the swirl of air.

 

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