DE1945921A1 - Combustion chamber - Google Patents

Description

ENGINE AND TURBINE UNION
MUNICH GMBH.

Munich, September 5th, 1969

Combustion chamber

The invention relates to a combustion chamber for gas turbine engines, whose flame tube is equipped with openings for the admixture of secondary air.

The secondary air admixture in the combustion chamber of the combustion chamber is provided in order to increase the amount required for the combustion process To supplement air requirements.

It is known that in a gas turbine engine the compressor end pressure increases with increasing speed and thus the amount of combustion air conveyed by the compressor to the combustion chamber, the amount of fuel to be supplied to the combustion chamber also increasing. Based on the well-known conditions ser prepares it remains difficult to provide a combustion chamber, which is characterized over a wide operating range by a good burn-out, low Druekverluste, a favorable ZUnd- and VerlÖBchverhalten.

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In an effort to reliably ignite the fuel / air mixture in the primary zone of the combustion chamber and furthermore to achieve a relatively good degree of efficiency of the combustion chamber in the partial load operation of the gas turbine engine, the inflow cross-sections for the primary and secondary air are selected to be relatively small in known combustion chambers. However, this measure leads to increased pressure losses in the full load range of the gas turbine engine.

In addition, it cannot be ruled out that, in such known combustion chambers, the inflow cross-sections chosen to be relatively small are already too large for reliable ignition of the fuel / air mixture and a faultless one To be able to achieve burnout of the combustion chamber during the starting process of the gas turbine engine, since the inflow speed the primary air is very low during the start-up phase. This particularly applies to the combustion chambers of gas turbine engines, which are equipped with a heat exchanger.

The invention is therefore based on the problem of addressing these disadvantages in known combustion chambers within the framework of the problems outlined to eliminate and to create a combustion chamber, which extends over the entire operating range of a gas turbine engine due to a good degree of burnout as well as further low ones

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Pressure losses, especially at full load and further through a characterized by favorable ignition and extinguishing behavior.

The invention proposes to solve the problem a combustion chamber of the type mentioned at the beginning, that the inflow cross-sections for the secondary air are variable.

According to the invention, the inflow cross-sections can also be a function be variable from the compressor discharge pressure or the combustion chamber inlet pressure.

The invention enables, for example, during the starting process of the gas turbine engine to partially or completely close the inflow cross-sections for the secondary air, whereby the amount of primary air is increased. This has an advantageous effect on the ignition behavior and the burnout of the combustion chamber and also enables a higher amount of fuel during the acceleration phase, as a result of which the gas turbine engine reaches the rated speed more quickly. With increasing The speed and the resulting increasing compressor pressure can continuously increase the inflow cross-sections for the secondary air so that with appropriate dimensioning of the inflow transverse section, the pressure loss at full load of the gas turbine engine can be kept very low.

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In a further, expedient embodiment of the subject matter of the invention can be axially or in the circumferential direction of the combustion chamber to change the inflow cross-sections, the Outer jacket surrounding the flame tube may be provided. This outer jacket can be equipped with openings, the cross-sections of which and shapes correspond to those of the inflow cross-sections of the flame tube, so that in one end position this Outer jacket, for example for the full load operation ™ of the gas turbine engine, the inflow cross-sections of the flame tube can be fully open.

According to the invention, the outer jacket can be displaced by an actuator, for example a spring-loaded piston. The piston can thus be used as control variables for the under the effect of the compressor end pressure or the combustion chamber inlet pressure Inflow cross sections are actuated.

k An embodiment of the invention is detailed below explained in the drawings; is in the drawings

Fig. 1 is the central longitudinal section of an according to the invention Combustion chamber and

FIG. 2 is a section along the line A-B of FIG. 1.

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Figure 1 illustrates the invention in a reverse combustion chamber, whose outer housing 1 runs out on the left side in a fuel injection cone 2, which is centered by a Fuel injector J5 is penetrated. Running coaxially to the longitudinal axis 4 of the reverse combustion chamber is in the outer housing 1 a flame tube 5 used, which on the left - between the outer housing 1 and the injection kergel 2 - a rounded Has edges equipped, bead-like displacement body 6, whereby a flow-favorable primary air reversal channel 7 is created. The primary air reversal duct is via a between the outer housing 1 and the flame tube 5 formed annular channel 8 in the direction of arrow F of compressor air a gas turbine engine not shown in the drawings flows through. The compressor air is used as the primary air via this primary air reversal channel 7 into the flame tube 5

With 9 are circular and with Io are slot-like inflow cross-sections for the supply of a part of the flowing into the annular channel 8 and from this into the flame tube 5 Secondary air designated (arrow direction G).

The secondary air can only enter the flame tube via the inflow cross-sections 9, Io flow in when an outer jacket 11 movably enclosing the flame tube 5 as far in the circumferential direction (Arrow H) of the combustion chamber is rotated until its associated openings, for example 12 (Fig. 2), the inflow

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Release cross-sections Io. The same applies to in the drawings Not shown, circular openings of the outer shell 11, which if necessary, depending on the movement of the outer shell 11 (arrow H), the inflow cross sections 9 can more or less free. The inflow cross-sections 13 of the flame tube 5 are in the present example unaffected by the movement of the outer jacket 11.

A depending on the increasing compressor pressure (arrow V) Fig. 2) via a line 14 in a housing 15 against a return spring 16 displaceable piston .17 is connected to an actuator 19 displaceably arranged in an elongated hole 18 of the outer housing 1, which is in a holder 2o (Fig. 1) of the outer jacket 11 engages. In this way, the inflow cross-sections 9, Io are variable or, if necessary, completely closable depending on the compressor end pressure, for example for the start-up process of the gas turbine engine, as can be seen from the position of the inflow cross-section Io to the opening 12 of the outer shell 11, according to FIG. 2.

The invention can also be used in purely annular combustion chambers or, for example, in the case of combustion chambers with an annular outer housing and several individual flame tubes inserted therein.

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Claims (5)

sr / kn S ENGINE AND TURBINE UNION
MUNICH GMBH. Munich, September 5th, 1969 Claims / 1. ^ Combustion chamber for gas turbine engines, the flame tube with Inflow cross-sections is equipped for the secondary air, characterized in that the inflow cross-sections (9, lo) for the secondary air are variable. 2. Combustion chamber according to claim 1, characterized in that the inflow cross-sections (9, lo) as a function of the compressor end pressure or the combustion chamber inlet pressure variable are. J. Combustion chamber according to Claims 1 and 2, characterized in that that to change the inflow cross-sections an axially or in the circumferential direction of the combustion chamber, the flame tube (5) enclosing the outer jacket (11) is provided. 4. Combustion chamber according to claims 1, 2 and 3, characterized in that that the outer jacket (11) can be displaced by an actuator, for example a spring-loaded piston (I7) is. 109813/0796 Blank page