CN204213971U - Premixed swirl formula nozzle on duty - Google Patents

Abstract

The utility model proposes a premixed swirl type duty nozzle. The gaseous fuel nozzle is connected to the air swirl pipe through threads, the on-duty premix chamber, the petal swirler and the zoom nozzle are connected to the air swirl pipe through welding, and the gaseous fuel nozzle extends into the duty premix chamber part in the circumferential direction. There are a number of evenly arranged fuel injection holes, and the air swirl tube has two symmetrical air swirl inlets along the tangential direction of the tube wall. There are several oblique air holes inside the petal swirler, and the middle part of the tube wall of the telescoping nozzle faces A ring-shaped nozzle throat protrudes inside. This type of on-duty nozzle can be installed in the main nozzle of a gas turbine burning gaseous fuel through structural adjustment, and the stable operation of the on-duty nozzle and the low emission characteristics of the gas turbine can be realized directly through fuel adjustment. It can also effectively ignite the main nozzle, and at the same time widen the lean-burn flameout range of the combustion chamber, greatly improving the working stability of the combustion chamber.

Description

Premix swirl duty nozzle

Technical field:

The utility model relates to the field of thermal energy and power engineering, in particular to a premixed swirl type on-duty nozzle of the core part of a gaseous fuel nozzle of a low-emission gas turbine combustion chamber.

Background technique:

With the diversification of energy types, the wide application of gas turbines and the deteriorating environmental pollution, people's environmental protection concept is increasing day by day. Countries around the world continue to introduce more and more stringent pollutant emission standards. And CO emission requirements are more stringent, low emission has become one of the important performance indicators of advanced gas turbines;

From the perspective of pollutant emission control, it is best to use lean-burn premixed combustion technology in the combustion chamber, which requires enough air to enter the main combustion zone through the fuel nozzle, so the main combustion hole and the mixing hole are no longer reserved on the flame tube. The temperature of the combustion zone is lowered through the combustion organization, which is beneficial to reduce NOx emissions. However, when the temperature in the combustion zone is low, the combustion stability becomes poor, and the danger of flameout is prone to occur. The biggest problem faced by the lean-burn premixed combustion technology is the decrease in combustion stability and the backfire of the premixed chamber. Due to the change of load or the change of fuel calorific value and composition, there is often the danger of flameout, which significantly threatens the operation safety of gas turbines. Since the combustion process in the combustion chamber is difficult to organize, special measures must be taken to ensure the stability of the flame while ensuring low pollutant emissions. It is necessary to adopt a special method for complex design of the nozzle structure. The introduction of duty nozzles in the center of the main nozzle can effectively improve the stability of the flame. Therefore, the research on the premixed swirl duty nozzle has important application value.

Utility model content:

The utility model is developed for solving the lean-burn flameout problem of the low-emission combustion chamber, improving the flame stability, and integrating the technical characteristics of the gaseous fuel main nozzle.

The technical solution of the utility model is: the premixed swirl nozzle on duty, including the gaseous fuel nozzle, the gaseous fuel nozzle and the air swirl pipe are connected by threads, and the duty premixing chamber, the petal type swirl and the scaling nozzle are welded Connect with the air swirl tube.

The gaseous fuel nozzle has a counterbore-shaped fuel inlet in the center, and a number of uniformly arranged fuel injection holes are opened in the circumferential direction of the part of the gaseous fuel nozzle extending into the on-duty premixing chamber.

Said air swirl pipe has two symmetrical slot-shaped air swirl inlets along the tangential direction of the pipe wall.

The petal-type cyclone described above has a number of oblique air holes radiating along the center inside the petal-type cyclone, and a straight hole is opened in the center.

In the telescoping nozzle, on the inner side of the nozzle outlet, the middle part of the pipe wall bulges inwards with an annular nozzle throat.

The utility model has the following beneficial effects: the premixed swirl type duty nozzle proposed by the utility model, this type of duty nozzle can be installed in the main nozzle of the gas turbine burning gaseous fuel through structural adjustment, and the duty nozzle can be directly adjusted through fuel adjustment. Stable work and low emission characteristics of the gas turbine, the petal-type swirler is adopted, which solves the technical defect of the swirler design that the flow rate is insufficient at a small hub ratio and does not meet the design criteria of the swirler at a large hub ratio; the use of fuel and air preheating The mixed form reduces pollutant emissions; the double-stage swirl method is adopted to strengthen the mixed cyclone flow; the zoom nozzle is used to accelerate the airflow at the throat to prevent tempering, and a low-speed recirculation zone is formed in the gradual divergence section to stabilize the flame on duty. Under the premise of stable combustion, the main nozzle can be ignited effectively, and at the same time, the lean-burn flameout range of the combustion chamber is widened, and the working stability of the combustion chamber is greatly improved.

Description of drawings:

Fig. 1 is the structural representation of the utility model;

Accompanying drawing 2 is the M direction view of accompanying drawing 1;

Accompanying drawing 3 is the A-A sectional view of accompanying drawing 1;

Accompanying drawing 4 is the B-B sectional view of accompanying drawing 1.

In the figure 1-gas fuel nozzle; 2-air swirl pipe; 3-duty premix chamber; 4-petal swirler; 5-zoom nozzle; 6-fuel inlet; 7-air swirl inlet; 8- Fuel injection hole; 9-oblique air hole; 10-nozzle throat; 11-nozzle outlet; 12-thread.

Detailed ways:

Below in conjunction with accompanying drawing, the utility model is further described:

As shown in Fig. 1 combined with Fig. 2 to Fig. 4, the premixed swirl nozzle on duty includes a gaseous fuel nozzle 1, the gaseous fuel nozzle 1 and the air swirl pipe 2 are connected by threads 12, the premixed chamber on duty 3, the petal type The swirler 4 and zoom nozzle 5 are connected with the air swirl pipe 2 by welding.

The gaseous fuel nozzle 1 has a counterbore-shaped fuel inlet 6 in the center, and a number of uniformly arranged fuel injection holes 8 are opened in the circumferential direction of the part of the gaseous fuel nozzle 1 extending into the duty premixing chamber 3 .

The air swirl pipe 2 has two symmetrical slot-shaped air swirl inlets 7 along the tangential direction of the pipe wall.

The petal-type cyclone 4 is provided with a number of oblique air holes 9 inside the petal-type cyclone 4, and a straight hole is opened in the center. On the one hand, the flow rate of the nozzle on duty can be improved, and on the other hand, it can assist in preventing the tempering of the flame on duty. Anti-petal cyclone ablation.

Said telescoping nozzle 5 has an annular nozzle throat 10 raised inwards in the middle of the pipe wall at the inner side of the nozzle outlet 11 .

The gaseous fuel enters the gaseous fuel nozzle 1 from the fuel inlet 6, and is injected into the on-duty premix chamber 3 from the fuel injection hole 8; at the same time, the air enters the on-duty premix chamber 3 in the form of a swirl flow through the swirl inlet 7, and is mixed with the fuel gas. Mix, then flow through the petal-type cyclone 4, further strengthen the swirl, through the zoom nozzle 5, accelerate at the nozzle throat 10, after flowing out at a high speed, suddenly expand and decelerate through the gradual expansion section to form a recirculation zone, the premixed gas A stable combustion flame is formed in the recirculation zone of the diverging section, and the flame is ejected from the nozzle outlet 11 and connected to the recirculation zone of the main nozzle, thereby igniting the main nozzle and widening the lean-burn flameout boundary of the main nozzle.

The fuel flow rate of this type of nozzle on duty can be adjusted according to the working conditions. The fuel volume can be reduced under relatively stable high working conditions, and the inflowing air directly enters the combustion zone to supplement oxygen and reduce pollutant emissions; under low working conditions, the fuel volume is appropriate Increase to form a stable duty flame and improve the combustion stability of the main flame.

Claims (5)

1. a premixed swirl formula nozzle on duty, comprise gaseous fuel nozzle (1), it is characterized in that: gaseous fuel nozzle (1) is connected by screw thread (12) with air swirl pipe (2), premix chamber (3) on duty, petal type cyclone (4) and pantographic nozzle (5) are connected with air swirl pipe (2) by welding.

2. premixed swirl formula according to claim 1 nozzle on duty, it is characterized in that: described gaseous fuel nozzle (1), center has the fuel inlet (6) of a counterbore shape, and gaseous fuel nozzle (1) stretches into premix chamber (3) part-circular periphery direction on duty and has some fuel orifices (8) be evenly arranged.

3. premixed swirl formula according to claim 1 nozzle on duty, is characterized in that: described air swirl pipe (2), has two symmetrical long hole shape air swirl entrances (7) along tube wall tangential direction.

4. premixed swirl formula according to claim 1 nozzle on duty, it is characterized in that: described petal type cyclone (4), have some centrally radial oblique pores (9) in petal type cyclone (4) inside, offer straight hole at center.

5. premixed swirl formula according to claim 1 nozzle on duty, it is characterized in that: described pantographic nozzle (5), inboard at jet expansion (11), the nozzle throat (10) of an inside protuberance ring-type in the middle part of its tube wall.