DE1947762A1 - Combustion chamber for gas turbines - Google Patents

Description

JOSEPH LUCAS (INDUSTRIES) LIMITED Birmingham (UK)

Combustion chamber for gas turbines

The invention relates to combustion chambers for gas turbines. Its purpose is to create a combustion chamber in an appropriate form.

A combustion chamber according to the invention has a primary air inlet duct, Secondary air inlet nozzles and dilution air inlet nozzles, the respective air inlet point being a fluidic air flow control device contains, which is arranged so that the parts of the entering through the respective air inlet points Total air flow can be changed without changing the total resistance of the combustion chamber to the air flow flowing through.

Wa / Hö ■ - 2 -

0098U / U23

The invention is described below on the basis of exemplary embodiments explained in more detail with reference to the drawings.

In the drawings are:

Fig. 1 A detail in section through a ring

shaped combustion chamber as an embodiment the invention,

Fig. 2 is an enlarged detail from Pig. I.

and

Pig. 5 and 4 are schematic representations of two views

part of a combustion chamber in an alternative embodiment. ♦

The combustion chamber b- 'has an inner wall 10 and an outer wall 11 which are formed so that they unite in a round front end in which primary air inlet ducts 12 are formed. The respective primary air inlet guide 12 has a swirler 13 which contains Eegel nozzle holes 14 through which air under high pressure can be introduced. These holes

14 are arranged around the outer periphery of the swirler 13, so that when compressed air is introduced, the effective cross section of the swirler is reduced in terms of pressure medium by reduce the flow of air through the primary air inlet ducts. Conversely, when air is blown through the holes 14 of the effective cross section of the swirler is enlarged in terms of pressure medium in order to increase the air flow through the primary air inlet guide.

The walls 10 and 11 of the combustion chamber at the inlet end thereof are provided with secondary air inlet nozzles 15 which extend inwardly through directed puddles are formed on the walls. The nozzles

15 is assigned an annular shell 16 which has an annular air chamber 17 forms. Holes are drilled in the puddles which open into the nozzles 15 on the inlet sides thereof. If the Chambers 17 are acted upon with air under high pressure, occur Jets of air into the nozzles 15 and throttle the flow of air into the combustion chamber in terms of pressure medium. On the other hand, if the

0098U / U23 _{& AD}

Kanunern 17 is withdrawn, the effective (cross-section of the Nozzles 15 enlarged, so that an increased air flow through the nozzles 15 is effected.

The walls 10 and 11 have the nozzles 15 downstream dilution air inlet nozzles 18, which are similar to nozzles I5. These nozzles 18 similarly have associated fluidic flow control devices, which are formed by bores in the nozzle flanges which open in chambers 19 to which air is supplied is to reduce the effective area of the nozzles 18, and from which air is extracted, to the effective area to increase.

By having the fluidic control bores only on the inlet side of the nozzles are provided, there arises the effect of changing the direction of the air flow through the nozzles and reducing the effective one Cross-sectional area of the nozzles.

Under operating conditions of the turbine, such as the smaller overall mixing ratios of air and fuel for the combustion chamber are assigned, for example exit flight conditions of aircraft, the fluidic devices, as described above, are operated so that the flow through the primary and secondary air nozzles is reduced to a minimum while air is drawn from the chambers 19 to allow air to flow through to increase the nozzles 18 to a maximum. In running conditions of the turbine, the higher total mixing ratios of air and fuel for -the combustion chamber are assigned, for example in aircraft take-off conditions, the supply of compressed air to the holes 14 is cut off and air is released from the chambers 17 deducted so that the primary and secondary air flows are increased. The chambers 19 are pressurized to reduce the dilution air flow. That changes the scheme of the airflow in the combustion chamber in such a way that the amount of air available to the burners is increased, which is in the suffered by the respective swirlers 15 are located. The change in direction of the secondary air flow

0098U / U23

BATH

causes an increased backflow of secondary air to increase the hatred of mixing fuel and air.

The top half of the pig. Fig. 1 shows low flow air flow conditions and the lower half shows conditions as they exist at high flow.

The fluidics used in nozzles 15 and 18 may alternatively take the form of vortex enhancers such as that in Pig. 5 ^and 4. Hegel bores are provided that can direct tangential air jets into the nozzles in order to create a turbulence that effectively reduces the cross-sectional area of the nozzles.

In one case, as in the other, the cross-sectional areas are of the nozzles, the sizes of the control bores and the control pressures used are selected so that there is no change in the total resistance the combustion chamber occurs against an air flow when a change from one flow state to another is taking place.

Claims;

0098 U / U2 3 * BAD

Claims (6)

Claims 1./ Combustion chamber for gas turbines, marked through a primary air inlet guide (12), secondary air inlet nozzles (15) and dilution air inlet nozzles (IB), wherein the respective air inlet point a fluidic air flow igloo device contains, which is arranged so that the parts of the entering through the respective air inlet points Total air flow can be changed without changing the total resistance of the combustion chamber to the air flow flowing through are. 2. Combustion chamber according to claim 1, characterized in that e t that the primary air inlet guide (12) contains holes (I4), can be introduced or withdrawn through the air in such a way that the effective cross section of the guide (12) increases or decreases can be. p. A combustor according to claim 2, characterized in that the holes are formed (I4) in outer <u ^e periphery of the guide (12). /]. Combustion chamber according to one of Claims 1-5, characterized in that that the secondary inlet nozzles (15) are formed by inwardly directed flanges on the walls of the chamber are. 5. Combustion chamber according to one of claims 1-4 »characterized in that that the dilution air inlet nozzles (18) through inwardly directed flanges on the walls of the chamber are formed. 6. A combustor according to claim 4 or 5 »characterized in that the flanges are provided with holes at the sides of inlet" transit the air so introduced or peelable 390 Wa / Hö - 2 - 0098U / U23 BATH ORIGINAL is that the effective cross-sectional areas of the nozzles (15 "or 18) can be decreased or increased. 7 · Combustion chamber according to claim 4 or 5 »characterized in that that the flanges are provided with holes through which the air, which is under high pressure during operation, is tangential can be introduced into the nozzles (15 or 18). Combustion chamber according to one of claims 1-4 »characterized in that that ring-shaped parts (16) surround the flanges and, together with these, ring-shaped air chambers (17) form. BAD OBtOtNAL 009814/1423 Blank page