CN111520756B

CN111520756B - Variable cross-section centrifugal nozzle

Info

Publication number: CN111520756B
Application number: CN202010215611.3A
Authority: CN
Inventors: 张群; 李小龙; 胡凡; 程祥旺
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2022-03-15
Anticipated expiration: 2040-03-25
Also published as: CN111520756A

Abstract

The invention provides a variable cross-section centrifugal nozzle, and relates to the field of aviation gas turbine combustors. The invention improves a single-oil-way centrifugal nozzle, which comprises a thermal protection layer, an air sleeve, a circumferential air ring, a circumferential fuel oil ring, a rolling hub, an adjustable wall surface of a swirling flow cavity and a nozzle outlet expansion section. The wall surface of the rotational flow chamber is adjustable, the horizontal section at the outlet of the nozzle is changed into a horizontal-expansion section, so that oil with different pressures can form proper rotational flow, and a variable-range oil film is formed at the outlet to ensure the stability of the atomization effect; in addition, the air sleeve is arranged outside the nozzle oil inlet pipeline, the thermal protection layer is arranged between the air sleeve and the oil inlet pipeline and on the periphery of the air sleeve, carbon deposition in a pipe wall cannot be caused due to the influence of external heat in an oil inlet process, and meanwhile, air flow and fuel gas flow are equalized to flow into the swirl cavity and are mixed in the swirl cavity, so that preliminary premixing of oil gas is realized, the fuel oil atomization effect is better, and the combustion efficiency is improved.

Description

Variable cross-section centrifugal nozzle

Technical Field

The invention belongs to the field of aviation gas turbine combustors, and particularly relates to a variable-section centrifugal nozzle.

Background

The basic performance and structural distribution of modern aircraft gas turbines has reached a fairly high level, but there are still a number of challenges and challenges for the combustors of aircraft gas turbines. In order to improve the overall performance of the combustion chamber of the aircraft engine, the internal fuel atomization effect is important, the quality of the atomization effect determines the working characteristics of the combustion chamber, and a proper nozzle needs to be designed for complete mixing of fuel and air and uniform spatial distribution of the fuel.

The fuel nozzle is always used as an important part of an aviation gas turbine to be explored, the performance of the fuel nozzle directly influences the normal stable working range of a combustion chamber, and meanwhile, the fuel nozzle also has important influence on the service performance, the thrust and the working economy of the gas turbine.

The fuel nozzle is a special nozzle for atomizing fuel, can generate hollow and solid spray shapes, and generally has spray angles of 30 degrees, 45 degrees, 60 degrees and 80 degrees. At present, a plurality of aviation gas turbines adopt a double-oil-way centrifugal fuel nozzle or a direct injection fuel nozzle as a starting nozzle or a working nozzle, the double-oil-way nozzle is composed of two single-oil-way nozzles which are concentrically arranged, and when the flow is small, only a first-level nozzle is adopted, so that the atomization quality is good; when the flow is large, the process of switching from the primary nozzle to the secondary nozzle exists, the atomization defect exists in the process, the spray angle deviates from the design value, the atomization effect is poor, the manufacturing and assembling processes of the whole nozzle are very complex, and the technical requirement is high; the direct injection type nozzle has a small equivalent diameter, so that the problem of nozzle blockage is easily caused, and obvious total pressure loss is caused.

The improved single-oil-way centrifugal fuel nozzle is applied to the field of combustion chambers of gas turbines, the application range of the fuel nozzle is expanded by designing the wall surface of the nozzle and the adjustable taper angle of the outlet, the swirl effect is better under the action of preventing carbon deposition in the nozzle, the fuel atomization quality is better, and the combustion efficiency is ensured.

Disclosure of Invention

The invention aims to provide a variable cross-section centrifugal nozzle. Compared with the prior art, the invention has the advantages that the single-oil-way centrifugal nozzle swirl cavity and the nozzle outlet are improved, so that the space size of the swirl cavity and the outlet cone angle are adjusted to proper positions along with the change of the flow and the pressure of the incoming fuel, and the stability of the outlet atomization area and the atomization effect is ensured. And then a layer of air sleeve is laid in the process of oil spraying pipeline section, so that carbon deposition caused by the influence of external heat flow temperature on the pipeline space can be effectively prevented, and air flow of the air sleeve is finally mixed with fuel oil in the vortex cavity, thus achieving the effect of preliminary premixing, improving the indoor pressure and being beneficial to the ejection of the fuel oil.

Technical scheme

The invention aims to provide a variable cross-section centrifugal nozzle which can prevent carbon deposition in the nozzle, simultaneously has better swirling effect and better fuel atomization quality, and ensures the combustion efficiency. .

The technical scheme of the invention is as follows:

the utility model provides a centrifugal nozzle of variable cross section, includes oil supply line, heat insulating sleeve, whirl chamber, adjustable wall and adjustable cone angle, its characterized in that: based on the defects of fixed oil injection range and poor atomization effect of the traditional oil nozzle, the single-oil-way centrifugal nozzle is reasonably improved, the space size of a rotational flow cavity is set to be adjustable, the horizontal section of the outlet of the nozzle is changed into a variable expansion section, and the improved part can form proper rotational flow for oil mass coming from different pressures and form a variable-range oil film at the outlet so as to achieve stable atomization effect; in addition, a layer of air sleeve is arranged outside the nozzle oil inlet pipeline, so that carbon deposition in the pipe wall caused by external heat influence in the oil inlet process is avoided.

The single-oil-way centrifugal nozzle is characterized in that: the space of the swirl chamber of the centrifugal nozzle is adjustable, when the introduced oil quantity is small, the oil injection pressure required by the nozzle is also low, the wall surface of the swirl chamber can be adjusted to expand outwards under the stretching action of the spring, the included angle between the wall surfaces is contracted to about 100 degrees, the space is large, and the swirl is generated by fuel oil under the condition of small flow; when the oil mass that lets in is great, former single oil circuit centrifugal nozzle needs bigger pressure, when adopting the adjustable nozzle in whirl chamber, slightly adds pressure, and adjustable whirl chamber wall contracts towards the adduction, and two wall contained angles are about 150, and the interior space is less this moment, can regard as to increase whirl intracavity pressure, produces the great swirl of speed with large-traffic fuel, does benefit to the export blowout. The outlet of the centrifugal nozzle is changed from a parallel section into an expansion section, the included angle of the expansion section is still adjustable, and when the oil quantity is small and the pressure is small, the expansion angle is about 90 degrees to obtain better atomization quality; when the oil quantity is larger and the pressure is slightly larger, the angle of the expansion section is expanded to 120 degrees, and the injection area is increased. A layer of air sleeve is arranged outside an oil inlet pipeline of the centrifugal nozzle, the inner wall surface of the sleeve is the outer wall surface of the nozzle, the outer wall surface of the sleeve is in a circular tube-shaped structure with the distance of about 3-5mm from the inner surface, and is finally mixed with fuel in a cyclone cavity for preliminary premixing, and the influence of external heat flow on the fuel in the nozzle is effectively isolated by the action of air in the sleeve, so that carbon deposition in the pipe is effectively prevented.

The invention has the following beneficial effects:

this kind of variable cross section centrifugal nozzle, compare in two oil circuit nozzle structures simpler, and can guarantee the stability of export atomizing area and atomization effect, can effectively prevent nozzle carbon deposit, and the air jacket air current is finally mixed with the fuel in whirl chamber, reaches preliminary pre-mixing's effect, has also improved indoor pressure, is favorable to the fuel blowout, improves the combustion efficiency of whole combustion chamber.

Drawings

FIG. 1: integral structure diagram of variable cross-section centrifugal nozzle

FIG. 2: cross-sectional view of the head of a variable cross-section centrifugal nozzle

In the figure: 1-a nozzle pipeline, 2-a nozzle head, 3-a nozzle outlet expansion section, 4-a support structure, 5-a thermal protection layer, 6-an air sleeve, 7-a fuel oil pipeline, 8-a circumferential air ring, 9-a circumferential fuel oil ring, 10-a swirl cavity, 11-a rolling hub and 12-an adjustable wall surface of the swirl cavity.

Detailed Description

The invention will now be further described with reference to the accompanying drawings in which:

with reference to fig. 1 and 2, the invention relates to a centrifugal nozzle with a variable cross section. FIG. 1 is an overall configuration view of a variable cross-section centrifugal nozzle, and FIG. 2 is a cross-sectional view of a head portion of the cross-section centrifugal nozzle.

In the process that fuel oil is introduced into the nozzle head part 2 from the nozzle pipeline 1 and is sprayed out of the nozzle, because the carbon deposition of the inner pipeline of the nozzle can be caused by hot airflow caused by combustion in the flame tube, a layer of air sleeve is distributed outside the fuel oil pipeline 7 to play a heat insulation role from the beginning of entering a combustion chamber, the heat protection layer 5 is adopted on the wall surface between the cold air sleeve 6 and the fuel oil pipeline 7 and the outer layer of the cold air sleeve 6, and the part of structure reaches the swirl cavity 10 in the nozzle to finish the structure, so that the double heat insulation role can be played, and the carbon deposition in the pipe can be prevented. Fuel flows into the nozzle head and flows to whole ring chamber through circumference fuel ring 9, and the air relies on the oil pressure effect that drives fuel to flow to whole ring chamber through circumference air ring 8, spouts into whirl chamber 10 from tangential groove 13 at last in, can effectively improve the intracavity pressure, realizes that the fuel air tentatively mixes in advance, has direct benefit to the injection effect of nozzle. The adjustable wall surface 12 of the swirl cavity and the nozzle outlet expansion section 3 act through the rolling hub 11 in the support structure 4, when the introduced oil quantity is small and the oil injection pressure is low, the wall surface of the adjustable swirl cavity contracts inwards under the stretching action of the spring, the space in the cavity is small, the fuel oil is favorable for generating swirl under the condition of small flow, the adjustable cone angle of the nozzle outlet is reduced, and the atomization distance is increased; when the oil mass is larger and the pressure is slightly larger, the wall surface of the swirl chamber expands outwards, the space is larger, the pressure in the swirl chamber is increased, large-flow fuel oil generates a swirl with higher speed, the swirl is favorably sprayed out to an outlet, the adjustable taper angle of the nozzle outlet expands, and the atomization area is increased. By designing the wall surface of the nozzle and the adjustable taper angle of the outlet, the application range of the fuel nozzle is enlarged, the rotational flow effect is better under the action of preventing carbon deposition in the nozzle, the fuel atomization quality is better, and the combustion efficiency is ensured.

Claims

1. The utility model provides a centrifugal nozzle of variable cross section, includes oil supply line, heat insulating sleeve, whirl chamber, adjustable wall and adjustable cone angle, its characterized in that: based on the defects of fixed oil injection range and poor atomization effect of the traditional oil nozzle, the single-oil-way centrifugal nozzle is reasonably improved, the space size of a rotational flow cavity is set to be adjustable, and the horizontal section at the outlet of the nozzle is changed into a variable expansion section; in addition, a layer of air sleeve is arranged outside the nozzle oil inlet pipeline, so that carbon deposition in the pipe wall caused by external heat influence can be avoided in the oil inlet process, and meanwhile, air flow and fuel gas flow into the vortex cavity to complete preliminary oil gas premixing.

2. A variable area swirler as claimed in claim 1, wherein: the space of the swirl cavity of the designed centrifugal nozzle is adjustable, when the introduced oil quantity is larger, the original single-oil-way centrifugal nozzle needs larger pressure, the wall surfaces of the swirl cavity can be adjusted to expand outwards under the stretching action of the spring, the included angle between the wall surfaces is contracted to form 90 degrees, the space is larger, and the swirl is generated by fuel oil under the condition of large flow; when the introduced oil quantity is small, the oil injection pressure required by the nozzle is also low, when the adjustable nozzle of the swirl cavity is adopted, slight pressure is applied, the wall surface of the adjustable swirl cavity is retracted inwards, the included angle between the two wall surfaces is about 120 degrees, at the moment, the indoor space is small, and the small-flow fuel oil generates a swirl with high speed, so that the small-flow fuel oil is favorably sprayed out to an outlet.

3. A variable area swirler as claimed in claim 1, wherein: the designed centrifugal nozzle outlet is changed from a parallel section into a parallel-expansion section, the included angle of the expansion section is still adjustable, when the oil quantity is larger and the pressure is slightly larger, the angle of the expansion section is expanded to 120 degrees, and the injection area is increased; when the oil quantity is small and the pressure is small, the divergence angle is about 90 degrees to obtain better atomization quality.

4. A variable area swirler as claimed in claim 1, wherein: a layer of air sleeve is arranged outside an oil inlet pipeline of the designed centrifugal nozzle, the thickness of the air sleeve is 3mm, a layer of thermal protection layer is arranged between the air sleeve and the oil inlet pipeline and on the periphery of the air sleeve, the thickness of the thermal protection layer is 2mm, the thermal protection layer is of a circular tube-shaped structure, and finally air and fuel oil flow into a rotational flow cavity through tangential grooves which are circumferentially arranged to be mixed to carry out preliminary premixing.