JPH03244904A - Burner for performing lean burning - Google Patents

Abstract

PURPOSE:To enable air of uniform temperature and high pressure to be stably supplied by a method wherein an inner cylinder is arranged in a combustion chamber so as to divide the combustion chamber into an inner combustion region of the inner cylinder and a passage for mixing air in the inner cylinder. CONSTITUTION:An interior part of a combustion chamber is divided into a combustion region 5 and a mixing air passage 7 by an inner cylinder 4. Both of them are merged from a downstream side near an expansion surface 4b of an outlet of the inner cylinder so as to form a mixing area. At the combustion region 5, fuel supplied from a fuel supplying injector 3 having a predetermined rate and oxidization agent supplied from an oxidization agent supplying chamber 2 through on oxidization agent supplying injector 20 are adjusted to have a state in which they may easily be burned, flow and then a stable combustion flame is formed. With such an arrangement, there is no disturbance of combustion so as to improve an energization characteristic and the combustion is quite stable. Mixing air flows through an oxidization (air) supplying chamber 2, an air supplying hole 2b and a mixing air passage 7 as well as an inner cylinder outlet air hole 2c and further becomes a flow directing toward a central part of the mixing region 6, resulting in that the air is sufficiently mixed with the flame got from the combustion region 5.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention addresses two important issues in a lean combustor for an air-intake jet test device: achieving stable combustion and equalizing the total temperature distribution at the exit of the combustion chamber. The present invention relates to a combustor that improves both of the above.

[Conventional technology]

In a conventional combustor, as described in NASA TND-7567, a combustion chamber 7 is formed by a plurality of injectors 6 that supply hydrogen gas 3 and oxygen gas 2 and air 4 flowing around them as shown in FIG. There is.

In this case, not only the combustion pressure fluctuates as shown in Figure 3, but the temperature at the outlet of the combustion chamber also changes as shown in Figure 4.
It exhibits a highly variable distribution.

Furthermore, as a prior art, there is a gas turbine combustor as shown in FIG. 5, which has a liner inside the combustion chamber.

This has a liner 4 inside the outer wall 1, and this liner 4
The air passage 3a communicates with the combustion chamber 5 via. However, in the case of a gas turbine, the length of the flame 6 varies because the fuel flow rate fluctuates depending on the operating conditions, so the liner is provided with many air passages 3a for film cooling and dilution air supply. Almost the entire length of the chamber and the length of the liner are equal. When the fuel flow rate increases, the air holes that used to supply secondary air may actually function to supply primary air.

[Problem to be solved by the invention]

The above conventional technology does not take into consideration the stability of combustion and the uniformity of heat supply, and it is necessary to limit the operating conditions to ensure combustion stability or to change the combustion chamber to make heat supply uniform. There was a problem with making it longer.

An object of the present invention is to supply stable, uniformly heated, high-temperature, high-pressure air to an air-intake engine testing facility.

[Means to solve the problem]

In order to achieve the above object, an inner cylinder is provided inside the combustion chamber, and the combustion chamber is divided into a combustion area inside the inner cylinder and a mixing air passage outside the inner cylinder. This makes it possible to maintain a mixture ratio of fuel and oxidizer that facilitates stable combustion in the combustion region, thereby preventing unstable combustion or combustion accompanied by pressure oscillations.

In addition, by shortening the length of the inner cylinder and making its end face trumpet-shaped and allowing the mixing air to flow toward the center of the combustion chamber through a large number of circular holes in its widening face, the distribution of heat supply at the combustion chamber outlet is achieved. is made uniform.

[Effect]

The inner cylinder acts as a separator that separates the combustion chamber from the passage through which the mixing air flows. As a result, no amount of air enters the combustion zone that would significantly alter the predetermined fuel to oxidizer ratio. In the second case, the heat resistance and thermal balance of the inner cylinder may be a problem, but the operating time is about 100 seconds at most, and the amount of heat entering from the combustion area and the amount of heat taken away from the passage side) So I know there is no problem.

In addition, by allowing the mixing air to flow toward the center of the combustion chamber through a large number of circular holes on the widening surface of the cylinder, the combustion gas and the mixing air are sufficiently mixed, and the gas temperature (heating) is increased at the exit of the combustion chamber.
distribution is uniform.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1 is the combustion chamber main body. 4 is an inner cylinder, and 2c is an inner cylinder outlet air hole provided on the inner cylinder outlet widening surface 4b. The interior of the combustion chamber is divided into a combustion region 5 and a mixing air passage 7 by the inner cylinder 4, and both are joined from downstream near the inner cylinder outlet widening surface 4b ending from the inner cylinder 4 to form a mixing region 6. In the combustion region 5, a predetermined ratio of fuel (H21C3H5, etc.) is supplied from the fuel supply injector 3, and an oxidizer (air, 02, etc.) is supplied from the oxidizer supply chamber 2 via the oxidized supply injector 2a. is adjusted to a highly combustible state (equivalent ratio φ=0.3 to 1.3) and flows in, forming a stable combustion flame.

As a result, in order to improve the starting characteristics (for example, shorten the time), if you suddenly start up the Arai well that supplies fuel and oxidizer and try to achieve a combustion state within a few seconds of starting, there will be no fluctuation in combustion, and the combustion will continue. Very stable. The mixing air is supplied from the oxidized (air) supply chamber 2. The flow flows toward the center of the mixing region 6 via the air supply hole 2b, the mixing air passage 7, and the inner cylinder outlet air hole 2c, and is sufficiently mixed with the flame from the combustion region 5. According to this embodiment, there is an effect that the temperature of the combustion gas can be uniformized at the exit end of the mixing region.

Furthermore, in this embodiment, the length 4a of the inner cylinder is set to the diameter 1 of the combustion chamber.
Even if it is shorter than 9, there is an effect that the above-mentioned stable combustion can be obtained.

〔Effect of the invention〕

According to the present invention, stable combustion can be ensured in the combustion region, and combustion gas and mixing air can be sufficiently mixed in the mixing region, which is effective in both combustion stability and uniform temperature supply. There is.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a combustion chamber of an embodiment of the present invention, FIG.
FIG. 5 is a longitudinal sectional view of the conventional embodiment, and FIGS. 3 and 4 are performance charts of the conventional embodiment. 1. Combustion chamber body, 1a.. Combustion chamber diameter, 2c. Inner cylinder outlet air hole, 4.. Inner cylinder, 4a.. Inner cylinder length, 4b. Inner cylinder exit widening surface, 5.. Combustion area. , 6...Mixed region,
7...Mixing air passage. Figure 3 Figure Wall Figure

Claims (1)

[Claims] 1. In a combustor for having high-temperature gas called a lean combustor, an inner cylinder is provided in the combustion chamber main body, and the inner cylinder is divided into a combustion region and a mixing region. A combustor that performs lean combustion, characterized by having an external mixing air passage 7. 2. A claim characterized in that the length of the inner cylinder is shorter than the diameter of the combustion chamber, and the mixing air flows toward the center of the mixing region through a plurality of inner cylinder outlet air holes provided on the widening surface of the inner cylinder outlet. A combustion chamber that performs lean combustion as described in 1.