CN114034060A

CN114034060A - Advanced pneumatic organization method suitable for concave cavity-cyclone combustion system

Info

Publication number: CN114034060A
Application number: CN202111072984.0A
Authority: CN
Inventors: 张凯; 金义; 姚康鸿; 王云飙; 吴迪; 金宝东
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2021-09-14
Filing date: 2021-09-14
Publication date: 2022-02-11

Abstract

The invention discloses an advanced pneumatic organization method suitable for a cavity-cyclone combustion system, wherein a main flow adopts cyclone airflow, and a front wall air inlet and a rear wall air inlet are adopted behind the main flow, and the distance between a front wall air inlet and the main flow cyclone airflow is smaller than the distance between a rear wall air inlet and the main flow cyclone airflow, so that the front wall air inlet is positioned between the cavity airflow and the main flow cyclone airflow to play a role in isolating the cavity airflow and the main flow cyclone airflow, thereby protecting a vortex structure in a cavity from being damaged by cyclone and further continuously and stably igniting main flow mixed air. The invention eliminates the adverse factor that the strong cyclone damages the flow structure of the concave cavity by designing the relative positions of the air inlet of the front wall and the air inlet of the rear wall of the concave cavity, thereby further improving the performance of the concave cavity or the cyclone combustion system.

Description

Advanced pneumatic organization method suitable for concave cavity-cyclone combustion system

Technical Field

The invention relates to the field of combustion, in particular to an advanced pneumatic organization method suitable for a concave cavity-rotational flow combustion system.

Background

Reentrant trapped vortex combustion is a new combustion organization developed since the 90 s of the 20 th century. The trapped vortex combustor employs staged combustion, including a class and a main combustion stage. The class generally consists of a cavity, inside which stationary vortices can be formed by a rational organization of the air fed into the cavity, which vortices are not sensitive to variations in the operating conditions of the combustion chamber due to their protection by the cavity; the oil-gas mixture of the main combustion stage enters the main combustion area and is ignited by the duty stage. The research work in recent 20 years obtains great results, and verifies the excellent performance of the trapped vortex combustor: good flame stability, high combustion efficiency, low nitrogen oxide emission and the like.

To the pneumatic tissue mode of traditional cavity, when following two kinds of circumstances appear, the mainstream gas stream receives the influence of whirl centrifugal force, to motion all around, extrudees the cavity air current, destroys stable swirl flame stabilizing structure in the cavity, and then leads to the cavity can't provide the gas mixture that the mainstream was lighted to the steady high temperature gas of continuation, can appear flameout phenomenon even when serious:

(1) the cyclone number is fixed, and the cyclone effect is strong due to large main flow;

(2) the large swirl number of the main flow swirler results in strong swirl effect.

The cyclone combustion adopts a cyclone to realize the tissue combustion in a large backflow area, and the combustion process of the cyclone combustion mode is stable and has small sensitivity to disturbance. Swirl combustion is widely applied to combustion chambers of aircraft engines as a classical combustion organization mode.

A great deal of research work is developed domestically aiming at the combustion chamber adopting the two pneumatic organization modes. On the basis of the research, a combination mode of the concave cavity and the rotational flow becomes a research hotspot of the combustion chamber, and a novel combustion system adopting a concave cavity/rotational flow pneumatic organization method is produced. But at the same time, the condition that the swirl airflow breaks the flow of the cavity occurs, which is not favorable for the stability of the cavity/swirl combustion system.

Disclosure of Invention

The technical problem to be solved by the invention is to provide an advanced pneumatic organization method suitable for a cavity-cyclone combustion system aiming at the defects involved in the background technology.

The invention adopts the following technical scheme for solving the technical problems:

an advanced pneumatic organization method suitable for a cavity-cyclone combustion system is characterized in that cyclone airflow is adopted as a main flow, a front wall air inlet and a rear wall air inlet are adopted behind the main flow, and the distance between an air inlet of the front wall and the main flow cyclone airflow is smaller than the distance between an air inlet of the rear wall and the main flow cyclone airflow, so that the front wall air inlet is positioned between the cavity airflow and the main flow cyclone airflow and plays a role in isolating the cavity airflow and the main flow cyclone airflow, the vortex structure in a cavity is protected from being damaged by cyclone, and main flow mixed air is continuously and stably ignited.

Compared with the prior art, the invention adopting the technical scheme has the following technical effects:

according to the invention, the traditional concave cavity flame stabilizing structure is modified, the inlet of the front wall air inlet after the main flow rotational flow airflow is close to the main flow, and the inlet of the rear wall air inlet is far away from the main flow, so that the front wall air inlet is positioned between the concave cavity airflow and the main flow rotational flow airflow, the front wall air inlet can play a role in isolating the concave cavity and the rotational flow airflow, the vortex structure in the concave cavity is protected from being damaged by the rotational flow, and the main flow mixed air can be continuously and stably ignited. The pneumatic organization method is suitable for a concave cavity-rotational flow combustion system, can widen the flame stabilization range, organize high-efficiency and stable combustion, and reduce the emission of pollutants.

Drawings

FIG. 1 is a schematic diagram of an advanced aerodynamic organization method for a re-entrant-cyclonic combustion system.

In the figure, 1-main flow swirl airflow, 2-cavity front wall air inlet, 3-cavity front wall air inlet channel, 4-cavity rear wall air inlet channel, 5-cavity rear wall air inlet and 6-cavity internal swirl flame stabilizing zone.

Detailed Description

The technical scheme of the invention is further explained in detail by combining the attached drawings:

the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, components are exaggerated for clarity.

Referring to fig. 1, a mainstream swirling air flow 1 passes through the combustion chamber and passes through the cavity exit region. The front wall intake air 2 enters the cavity area through the front wall intake passage 3. The rear wall intake air 5 enters the cavity through the rear wall intake air passage 4. The front wall inlet 2 and the rear wall inlet 5 form a vortex airflow structure in the concave cavity vortex flame stabilizing area 6. Meanwhile, because the front wall air inlet 2 is close to the main flow, the part of air flow plays a role of an air flow barrier, and the strong rotational flow 1 is prevented from entering the vortex flame stabilizing area 6 in the concave cavity under the action of centrifugal force to damage the vortex structure of the air flow.

After the main flow rotational flow is adopted, the inlet of the front wall air inlet is close to the main flow, and the inlet of the rear wall air inlet is far away from the main flow, so that the front wall air inlet is positioned between the cavity air flow and the main flow rotational flow air flow, the front wall air inlet can play a role in isolating the cavity and the rotational flow air flow, the vortex structure in the cavity is protected from being damaged by the rotational flow, and the main flow mixed air can be continuously and stably ignited. The pneumatic organization method is suitable for a concave cavity-rotational flow combustion system, can widen the flame stabilization range, organize high-efficiency and stable combustion, and reduce the emission of pollutants.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An advanced pneumatic organization method suitable for a concave cavity-cyclone combustion system is characterized in that a main flow adopts cyclone airflow, and a front wall air inlet mode and a rear wall air inlet mode are adopted behind the main flow, and the method comprises the following steps:

the distance between the front wall air inlet and the main flow rotational flow airflow is smaller than the distance between the rear wall air inlet and the main flow rotational flow airflow, so that the front wall air inlet is positioned between the cavity airflow and the main flow rotational flow airflow and plays a role in isolating the cavity airflow and the main flow rotational flow airflow, the vortex structure in the cavity is protected from being damaged by rotational flow, and the main flow mixed air is continuously and stably ignited.