JPH02126023A - Gas turbine combustor - Google Patents

Abstract

PURPOSE:To cause a temperature of an inner cylinder to be uniformly less than a design temperature by a method wherein a temperature of an inner cylinder of a combustor is measured and an orifice is installed in order to cool a position where a high temperature is found in its distribution of the temperatures. CONSTITUTION:Temperatures of an inner cylinder of a prior art combustor are measured for an entire area, an orifice 1 is mounted at a place showing a high temperature to perform a temperature measurement again. If there is a high or a low temperature and there is a place where the temperature exceeds a design temperature, an orifice mounting place is changed or additional orifice is set. A hoop to which the orifice 1 is fixed is welded to an inside part of an outer cylinder 3 of the combustor. The hoop is provided with a threaded hole so as to enable the orifice 1 to be fixed by a bolt in advance, and then a plurality of hoops are mounted in such a way as a fixing position of the orifice 1 may be selected to a certain degree. In this way, a temperature within the inner cylinder can be made uniform by setting one orifice to one place where a high temperature of the inner cylinder 6f the combustor is found and in turn by setting two orifices to the two locations where a high temperatures of the inner cylinder of the combustor are found.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gas turbine combustor, and in particular, the present invention relates to a gas turbine combustor, and in particular, it is possible to effectively cool the inner cylinder with minimum air flow resistance, and to design the inner cylinder temperature. Concerning an orifice designed to maintain temperature below.

[Conventional technology]

Conventional cooling of the combustor inner cylinder is described, for example, in Japanese Patent Application Laid-Open No. 59-22
This is done by adjusting the air flow using a straightening tube (flow sleeve) as described in Japanese Patent No. 9114. Although this is effective for cooling the transition tube, it is also effective for cooling the transition tube, which is the purpose of the present invention. Uniform cooling below the design temperature and minimizing air flow resistance cannot be achieved.

[Problem to be solved by the invention]

The above-mentioned conventional technology relates to cooling the inner cylinder of the combustor, but the upper limit is not placed on (1) making the temperature of the inner cylinder uniform and (2) minimizing the resistance of air circulation. However, effective cooling has not been achieved.

The objects of the present invention are (1) to make the inner cylinder temperature uniform and (2) to minimize the resistance of air circulation. A structure such as this is installed at a location where the temperature of the inner cylinder is lowered, and the installation position of the orifice is selected so that the temperature of the inner cylinder is uniformly below the design temperature.

[Means to solve the problem]

The above purpose is to first accurately measure the internal cylinder temperature of the combustor according to the prior art, and install an orifice in order to particularly cool the high temperature position in the temperature distribution.

[Effect]

Although the orifice of the present invention is useful for effectively cooling portions of the combustor liner, it is necessary to carefully investigate which portions of the liner should be cooled. For this reason, the temperature of the inner cylinder of a conventional combustor is measured over the entire area, an orifice is installed at a high temperature point, and the temperature is measured again. , change the location of the orifice, or install one more. In this way, through trial and error, it is possible to install an orifice with an appropriate structure, size, and number at an optimal position.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. This embodiment is a conventional example with an orifice 1 attached thereto. The figure shows a cross section of a gas turbine combustor, and also shows the flow system of air and hot gas. The compressor sucks atmospheric air and sends it to the combustor as compressed air. Compressed air leaving the compressor discharge casing 6 flows into a plurality of combustors arranged around the gas turbine shaft. The combustor includes a compressor discharge casing 6, a combustor outer cylinder 3, a barrel 7, a wrapper 5,
It forms part of a pressure vessel surrounded by the turbine first stage stationary blade 8 and the first stage server 1 to ring 9, and after compressed air enters this, it flows into the combustor inner cylinder 2. . The outer surfaces of the combustor inner pipe 2 and the combustor transition pipe 4 are cooled before flowing into the combustion chamber. In particular, by installing the orifice 1, the speed of compressed air passing through the gap between the orifice 1 and the combustor inner cylinder 2 increases, and the heat transfer coefficient of the outer surface of the combustor inner cylinder 2 increases.

Therefore, the outer surface of the combustor inner cylinder where the orifice 1 is installed is cooled more than other parts. The temperature of the combustor inner cylinder 2 varies depending on the model, capacity, structure, operating method, etc. of the gas turbine, and a typical example thereof is shown in FIG. In the figure, the inner cylinder temperatures without a flow sleeve and with a flow sleeve are for the conventional combustor structures shown in Figures 8 and 7, respectively. It can be seen uniformly along the length.

On the other hand, when the orifice of the present invention is installed, the temperature of the entire inner cylinder is kept at a substantially constant temperature by particularly cooling the high-temperature portion of the conventional example. FIG. 2 shows a second embodiment of the present invention;
The difference from the diagram is that two orifices 1 are installed. In Fig. 2, 1-1 and 1-2 are the orifices, and 6 orifices 1 are shown in Fig. 3, which are applied when there are two places where the temperature becomes high in the longitudinal direction of the combustor inner cylinder 2. Mounted on the hoop. A hoop-shaped hoop is welded to the inside of the combustor outer cylinder 3.

A screw hole is made in the hoop so that the orifice 1 can be fixed with a bolt. As shown in FIG. 3, a plurality of hoops are installed so that the mounting position of the orifice 1 can be selected to some extent. In this way, by installing one orifice in the position where the temperature of the combustor inner cylinder becomes high, if there is one orifice, or two orifices if there are two orifices, the temperature of the inner cylinder is uniform. It can be done. In Fig. 3, dimensions a and b determine the conditions for compressed air passing through the orifice gap, including the shape and dimensions of the combustor outer cylinder 3°, the inner cylinder 2, the temperature of the inner cylinder 2, the temperature of the compressed air, The optimum value is determined by pressure etc. The orifice angle d occurs when the compressed air passes through the gap a;

Usually, about 45 degrees is desirable. Since the flow velocity of the compressed air increases when passing through the gap a, and the heat transfer coefficient increases, the inner cylinder wall at the gap a can be efficiently cooled. The compressed air that has cooled the outer surface of the inner cylinder passes through the louvers of the inner cylinder, enters the inner cylinder, cools the inner surface of the inner cylinder, and then is supplied for combustion. Fig. 5 shows the case where the orifice gap a is constant on the circumference, and Fig. 6 shows the case where the orifice inner circle is eccentric, so the gap is not constant like a and a', and the temperature of the combustor inner cylinder 2. As long as the orifice shape is constant in the circumferential direction at a high position, the orifice shape may be an inner circle or concentric with the inner cylinder, and the gap shown in FIG. 5 is constant.

However, if the temperature changes in the circumferential direction, the orifice should be shaped so that the gap at the point where the temperature is highest is the minimum a', and the gap at the location where the temperature is not high is the maximum a' (see Figure 6). Set up. By doing so, the temperature of the combustor inner cylinder 2 can be made almost uniform in both the longitudinal direction and the circumferential direction. As mentioned above, the temperature of the combustor inner cylinder 2 depends on the gas turbine model, capacity, structure, operation method, combustion temperature,
The temperature distribution varies depending on the pressure, etc., and it is particularly difficult to accurately estimate the temperature distribution at the design stage. In order to find the shape of the orifice that cools the combustor inner cylinder 2 with the minimum pressure loss, it is necessary to repeat experiments by trial and error. Therefore, it is desirable to have a structure in which the shape of the orifice can be selected to some extent. If the temperature of the inner cylinder 2 is constant in the circumferential direction, the orifice gap a may be constant, and therefore the orifice inner diameter has a concentric structure with respect to the inner cylinder 2, but if the temperature of the inner cylinder 2 changes in the circumferential direction. If, as mentioned above, the orifice gap a is made by making the inner diameter of the orifice eccentric to the inner cylinder 2 as shown in a'(a').The outer diameter of the orifice is made concentric with the outer cylinder 3, By keeping the mounting bolt hole pitch constant, the mounting position can be set by turning the orifice so that the positions of the orifice gaps a' and a' match the positions where the temperature of the inner cylinder 2 is the highest and lowest. .

As for the longitudinal position, as shown in FIG. 3, a plurality of hoops are welded to the outer cylinder 3 at appropriate intervals so that the orifice mounting position can be selected.

In this way, the orifice 1 can be installed by selecting the position 'where the temperature of the inner cylinder 2 is the highest.

FIG. 4 shows the inner cylinder temperature distribution as a typical example of a conventional combustor, with and without a flow sleeve, and in the case of the present invention. In the example of a flow sleeve sub-material for a conventional combustor, the inner cylinder temperature increases, so the design temperature of the inner cylinder material should be increased as shown in (a), and a high temperature heat resistant material should be selected for the inner cylinder, or the combustion temperature should be lowered. It is necessary to reduce the output of the gas turbine by lowering it. In the example with a flow sleeve, the inner cylinder temperature is
Therefore, the design temperature of the inner cylinder material can be lowered as shown in (b), and the material for the inseam can be selected. Alternatively, high-temperature resistant materials can be selected to increase combustion temperatures and increase gas turbine output. However, in the case of a flow sleeve,
Since the air pressure loss from the compressor discharge to the combustor inner cylinder is relatively large, the increase in output is inhibited to some extent.
The overall effect of flow sleeve installation is small.

FIGS. 7 and 8 are representative examples of conventional combustors, with FIG. 7 showing a case with a flow sleeve and FIG. 8 showing a case with a flow sleeve child member. In Fig. 7, the cylindrical part between the inner cylinder 2 and the outer cylinder 3 is called a flow sleeve.
Since there are no holes, compressed air flows along the inside of the flow sleeve into the inner cylinder. If the flow sleeve is long, the resistance to the compressed air passing through it increases, causing a reduction in output and efficiency. Except for this flow sleeve and the orifice 1 shown in FIGS. 1 and 2, the structure of the combustor is basically the same for both the conventional type and the present invention. It is the same as

According to this example, if the conventional inner cylinder material is followed and the combustion temperature is assumed to be the same as with a flow sleeve, the pressure loss will be reduced by about 0.5 to 1.0% in absolute value, so the gas turbine output will be reduced. Efficiency increases by about 0.5-1.0% in relative terms. Not only is the cost reduced by changing from a flow sleeve to an orifice, but the construction cost per m output is also lower due to an increase in output;
It has a powerful effect.

〔Effect of the invention〕

According to the present invention, it is possible to cool the combustor inner cylinder so that the temperature is almost uniform, and the resistance of compressed air can be minimized. It is possible to select the material of the inner cylinder.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of the embodiment of the present invention, FIG. 3 is a detailed view of the orifice mounting part of FIG. 1, and FIG. 4 shows how the inner cylinder temperature changes in the longitudinal direction of the inner cylinder. FIGS. 5 and 6 are cross-sectional views of the orifice mounting portion, and FIGS. 7 and 8 are longitudinal cross-sectional views of a conventional combustor. 1... Orifice, 5... Wrapper, 7... Barrel, 9... First stage support ring.゛Kunino certain figure 1000-figure roots of a rod ＼ Mazu figure upper side - inside V ball 4 force gradient - tip of the 11th rod et al.

Claims (1)

[Scope of Claims] 1. In a gas turbine combustor comprising an inner cylinder, an outer cylinder, a transition piece, a fuel nozzle, and an air chamber, the inner cylinder is provided in a cooling air passage between the inner cylinder and the outer cylinder. A gas turbine combustor characterized by having one or more circular or elliptical orifices concentrically or eccentrically installed.