CN105650679A - Combustion chamber of ground combustion engine with premixed third-class rotational flow part - Google Patents

Abstract

The present invention provides a three-stage swirl partially premixed ground gas engine combustion chamber. The head of the combustion chamber includes three swirl tubes with increasing diameters around the same axis, and the two swirl tubes located on the inner side The inner swirl blades are evenly arranged around the axis, and the swirlers located in the outermost swirl tube are evenly arranged around the inner radial center of the outer annular swirl tube. The three-stage swirl design in different ways enables the combustion of the duty stage at the head to drive the combustion of the relatively high-speed premixed fuel flowing out of the outermost main combustion stage, which can improve the combustion speed of the main combustion stage and the combustion uniformity of the duty stage , which greatly reduces the NOx emissions of the combustion chamber under various loads, improves the combustion efficiency of the ground gas turbine combustion chamber, shortens the fuel residence time, and saves the combustion chamber space.

Description

A Three-Stage Swirling Partially Premixed Surface Gas Turbine Combustor

technical field

The invention relates to the field of gas turbines, in particular to a three-stage swirl partially premixed ground gas turbine combustion chamber.

Background technique

With the development of heavy-duty gas turbine technology, modern heavy-duty gas turbines pursue ultra-low pollution emissions, and at the same time develop in the direction of high temperature rise. The improvement of the overall performance of gas turbines puts forward higher requirements for the design of the main combustion chamber. For decades, the development goal has always been a higher average temperature of the combustion chamber outlet (standardized gas turbine technical level) and lower pollutant emissions; the above technical indicators are closely related to the combustion chamber and contradict each other. With more fuel participating in the combustion process, the average temperature in the combustion chamber is higher, and nitrogen oxides, which are the main pollutants in the combustion chamber, are closely related to the thermal process inside the combustion chamber. The basic function of the gas turbine combustor is to convert the chemical energy in the fuel into the thermal energy in the gas by organizing the flow of fuel and air at high intensity in a limited space and chemical reaction to drive the turbine to do work. Its core is the interaction between turbulent mixing process and chemical reaction kinetic process.

Dry low NOx (drylowNOx, DLN) combustion technology is based on the Zeldovich generation principle of thermal NOx, and the temperature of the main combustion zone of the combustion chamber is restricted within a narrow range of 1670-1900K to reduce NOx emissions. Therefore, premixed combustion must be adopted. The flame temperature is controlled by adjusting the fuel/air equivalence ratio in the main combustion zone. However, only controlling the average equivalence ratio can not meet the requirements. All DLN combustors require uniform fuel/air premixing. The key to dry low NOx (drylowNOx, DLN) combustion technology is to control the total fuel/air equivalence ratio in the main combustion zone of the combustor. Under the premise of achieving uniform premixing of fuel and air, the research and development of advanced DLN combustors in the world have spent a lot of energy on the issue of premixing uniformity.

Most of the existing DLN combustion chambers of heavy-duty ground gas turbines, in order to stabilize the combustion chamber flame, the center is designed as a duty class for diffusion combustion, which results in uneven mixing of fuel and air, and local high-temperature areas are prone to occur, resulting in NOx emissions are high. When the combustor of a general industrial heavy-duty gas turbine reduces the operating load, the fuel ratio of the duty class is usually increased to stabilize the combustion chamber flame. At this time, the pollution emissions of the duty class account for a larger proportion.

Contents of the invention

The technical problem to be solved by the present invention is to provide a ground gas turbine combustor with three-stage swirl and partial premixing, which can improve the uniformity of combustion and greatly reduce the NOx emission of the combustor under various loads. At the same time, the combustion efficiency of the combustion chamber of the ground gas turbine is improved, the fuel residence time is shortened, and space is saved.

The present invention solves the above-mentioned technical problems through the following technical means: a three-stage vortex partially premixed ground gas turbine combustion chamber. The swirl blades in the two swirl tubes are evenly arranged around the axis, and the swirls in the outermost swirl tube are evenly arranged around the radial center of the outer swirl tube. The fuel in the two outer annular swirl tubes is premixed in advance for premixed combustion.

The diameter ratio of the three swirl tubes at the head is 4:7:15, and the length is 200mm-210mm. The swirl vanes with an installation angle of 40-50° are installed in the swirl tube of the first layer (innermost layer) at a distance of 135-145 mm from the outlet, and the number is 8-10. The second layer (middle) of the swirl cylinder is equipped with swirl vanes with an installation angle of 0° at a distance of 5-10mm from the outlet, and the number is 24, which are evenly arranged around the axis of the combustion chamber; There are 16 swirl vanes with an angle of 5-8°, which are evenly arranged around the axis of the combustion chamber. The four fuel spray rods in the second swirl tube are connected with the fuel spray rods on duty, and are evenly distributed in the circumferential direction, with a length of 60-70mm.

Adopt the present invention can obtain following beneficial effect:

The three-stage swirl design in different ways enables the combustion of the duty stage at the head to drive the combustion of the relatively high-speed premixed fuel flowing out of the outermost main combustion stage, which can improve the combustion speed of the main combustion stage and the combustion uniformity of the duty stage , which greatly reduces the NOx emissions of the combustion chamber under various loads, improves the combustion efficiency of the ground gas turbine combustion chamber, shortens the fuel residence time, and saves the combustion chamber space.

Description of drawings

Figure 1: Axial front view of the present invention

Figure 2: Axial sectional view of the present invention

detailed description

Below in conjunction with accompanying drawing and embodiment the present invention will be described in further detail:

As shown in Figure 1, a three-stage vortex partially premixed ground gas turbine combustor in this embodiment, the head of the combustor includes three swirl tubes 1, 2 and 3 with increasing diameters around the same axis. , wherein the swirl vanes 5 and 4 in the two inner swirl tubes 1 and 2 are evenly arranged around the axis of the combustion chamber, and the swirlers 6 in the outermost swirl tube 3 are arranged around the outer annular swirl tube 3. The inner diameters are evenly arranged in the center. The diameter ratio of the three swirl tubes at the head is 4:7:15, and the length is 200mm-210mm.

As shown in Figure 2, the air enters the swirl cylinders 1, 2 and 3 from the head at the same time. The swirl cylinder 1 is located at the center and has the smallest diameter. The installation angle is 40-50° at a distance of 135-145 mm from the outlet. The number of swirl vanes 5 is 8 to 10. The swirl vanes 5 are installed on the duty-level fuel spray rod 8 on the axis. The distance between the fuel injection port 9 on the duty-grade fuel spray rod 8 and the swirl tube 1 is It is 70-75mm. The fuel and air mixture ejected from the swirl tube 1 is decelerated and depressurized through the expansion section, and mainly undergoes diffusion combustion.

As shown in Figure 2, the second layer (middle) annular swirl tube 2 is connected to the swirl tube 1 through the swirl blades 4 and 10, and a swirl tube with an installation angle of 5-8° is installed at a distance of 130-140mm from the outlet. The number of blades 4 is 16, and they are evenly arranged around the axis of the combustion chamber. The four fuel spray rods 7 in the second swirl tube are connected with the fuel spray rods 8 on duty, and are evenly distributed in the circumferential direction, with a length of 60-70 mm. After the air enters the interior of the annular swirl tube 2, it first passes through the swirl flow of the swirl vane 4, mixes with the fuel sprayed from the fuel spray rod 7, and finally flows out of the swirl tube for premixed combustion. The installation angle is 0° swirl flow The arrangement of blades 10 prevents the occurrence of flashback, and the number is 24, which are evenly arranged around the axis of the combustion chamber, and are 5-10 mm away from the outlet.

As shown in Figure 2, a number of independent swirlers 6 and matching fuel spray rods 11 are installed in the third layer of annular swirl tube 3, and the rotation centers of blades 6 of several swirlers are the corresponding fuel injection rods. pole 11. After the fuel enters the annular swirl tube 3, it first swirls through the swirl blades 6, then mixes with the fuel sprayed from the spray rod 11, and finally flows out through the converging section at an accelerated rate for premixed combustion of the main combustion stage.

The ground gas turbine includes several combustion chambers as above. The combustion chambers are evenly arranged along the circumferential direction of the unit, inserted obliquely into the casing and connected to the compressor cylinder to form a whole.

The above-mentioned embodiment is only a preferred embodiment of the present invention, and should not be limited to the protection scope of the present invention, and the specific implementation of the present invention is not limited to the above-mentioned embodiment. According to the above content of the present invention, according to common technical knowledge and conventional means in this field, without departing from the above-mentioned basic technical idea of the present invention, the present invention can also make other modifications, replacements or changes in various forms, all of which should fall into the following categories: Within the protection scope of the present invention.

Claims (5)

1. A three-stage swirl partially premixed ground gas turbine combustor, characterized in that the head of the combustor includes three swirl tubes with increasing diameters around the same axis, of which the two on the inner side The swirl vanes in the swirl barrel are evenly arranged around the axis of the combustion chamber, and the swirlers located in the outermost swirl barrel are evenly arranged around the radial center of the outer annular swirl barrel. 2. A three-stage vortex partially premixed surface gas turbine combustor according to claim 1, characterized in that the diameter ratio of the three vortex tubes at the head is 4:7:15, and the length is 200mm ~ 210mm. 3. A three-stage vortex partially premixed surface gas turbine combustion chamber according to claims 1 and 2, characterized in that the first (innermost) vortex cylinder is 135-145mm away from the outlet There are 8-10 swirl blades with an installation angle of 40-50°. 4. A ground gas turbine combustion chamber with three-stage swirl partly premixed according to claims 1 and 2, characterized in that the second layer (middle) swirl tube is installed at a distance of 5-10 mm from the outlet. There are 24 swirl vanes with an installation angle of 0°, which are evenly arranged around the axis of the combustion chamber; 16 swirl vanes with an installation angle of 5-8° are installed at a distance of 130-140mm from the outlet. The axis of the combustion chamber is evenly arranged. 5. According to claim 1, 3, 4, a three-stage swirl partially premixed surface gas turbine combustion chamber, characterized in that, the four fuel spray rods in the second layer swirl tube are connected with the on-duty The fuel spray rods of the two stages are connected to each other, evenly distributed in the circumferential direction, and the length is 60-70mm.