RU2245447C1 - Combustion chamber igniter - Google Patents

Abstract

FIELD: igniting main combustion chambers of aircraft gas-turbine engines.

SUBSTANCE: proposed igniter has cylindrical body with air admission hole and inner space with partition and three chambers. First chamber accommodates electrical ignition plug, second one holds fuel injector, and third chamber communicates with two first ones and with radial outlet pipe connection. Air admission hole is made in body wall between injector nozzle and partition. Partition has hole providing communication between first and second chambers; volume of the latter is more than twice as large as that of first chamber and ratio of third chamber volume to total volume of two first chambers is lower than 2 and higher than Ѕ. In addition oxidant inlet holes are provided in body wall of second chamber. Made in body wall of third chamber around radial pipe connection are holes disposed on same circumference, every next one having different diameter; ratio of total areas of holes of one diameter to those of other diameter is 2 to 2.5 and ratio of flow area of radial outlet pipe connection to total area of these holes is 8 to 9.

EFFECT: enlarged reliable ignition range of combustion chamber.

3 cl, 1 dwg

Description

The invention relates to aircraft engine building, in particular to igniters, intended primarily for the main combustion chambers, and can be used in the starting system of gas turbine engines.

A known igniter of a combustion chamber of a gas turbine engine, comprising a housing connected to the igniter tube, a deflector installed inside the housing, a spark plug, a fuel nozzle with a spray and a screen, the latter being made with cut out central sector and side segments and placed perpendicular to the axis of the spray, and the screen sector is directed in the direction of the spark plug (see patent of the Russian Federation No. 2083858, IPC 7 F 02 C 7/26, 07/10/1997).

However, such a design of the swirler does not provide a high degree of reliable ignition of the air-fuel mixture and reliability, since when the combustion chamber is started, the flame stabilizes at the edges of the screen sector and causes it to burn out.

A combustor igniter is also known, the closest in technical essence to the invention, containing a cylindrical body with an air inlet and an internal cavity with a partition and three chambers, the first of which is a candle, the second is a nozzle, and the third is in communication with the first two and with a radial output pipe (see application UK No. 1507815, IPC 7 F 02 C 7/266, 04/19/1978).

However, the known igniter in low gas modes has disruptions.

The objective of the invention is to expand the range of reliable ignition of the combustion chamber of a gas turbine engine.

The specified technical result is achieved due to the fact that the igniter contains a cylindrical body with a hole for supplying air and an internal cavity with a partition and three chambers, the first of which has an electric candle, the second has a fuel nozzle, and the third is connected with the first two and with radial the outlet pipe, while the hole for supplying air is made in the wall of the housing between the nozzle of the nozzle and the partition, in the latter there is a hole communicating the first chamber with the second, the volume of the second chamber s more than two times the volume of the first chamber and the third chamber volume ratio to the total volume of the first two chambers and at least two greater than 1/2. In addition, in the wall of the housing in the second chamber, additional openings are made for supplying an oxidizing agent, and in the wall of the housing of the third chamber around the radial nozzle, holes are made on the same circumference with different diameters through one, and the ratio of the total area of one hole to another is from 2 up to 2.5, and the ratio of the passage area of the radial outlet pipe to the total area of these holes is from 8 to 9.

The invention is illustrated in the drawing, which shows a longitudinal section of the igniter.

The igniter of the combustion chamber contains a cast cylindrical body 1 with an opening 2 for air supply and an internal cavity with a partition 3 with the formation of three chambers 4, 5 and 6, in the first of which there is a fuel nozzle 7, in the second - an electric candle 8, and the third chamber 6 communicated with the first two and with the radial outlet pipe 9. A hole 2 for supplying air is made in the housing 1 between the outlet nozzle 10 of the nozzle 7 and the partition 3, in the latter there is a hole 11 communicating between the first chamber 4 with the second chamber 5, volume V ₂ which more than doubles the volume V _{3 of the} third chamber 6 to the sum of the volumes (V ₁ + V ₂ ) of the first two chambers 4 and 5 is less than two and more than 1/2

.

.

In the housing 1 there are additional openings 12 for supplying an oxidizing agent, for example, oxygen, located in the second chamber 5 between the candle 8 and the partition 3.

In addition, in the wall of the housing 1, forming the third chamber 6 in front of the outlet, openings 13 and 14 are made for supplying air from the annular channel of the combustion chamber (not shown) to the third chamber 6 when operating without an oxidizing agent. The holes 13 and 14 are located on the same circle through one, taking into account the following relationships: the ratio of the total areas 13 and 14 is from 2 to 2.5 (∑F ₁₄ / ∑F ₁₃ = 2-2.5), and the ratio of the passage area the radial nozzle of the outlet pipe 9 to the total area of all holes 13 and 14 is from 8 to 9 (F _nozzle / F ₁₃ + F ₁₄ = 8-9).

The process of ignition of the air-fuel mixture is as follows.

From the output nozzle 10 of the nozzle 7, fuel (for example, kerosene) is supplied to the first chamber 4 in an amount sufficient for a large enrichment of the mixture. The received fuel in a significant amount settles on the partition 3 and is blown off in the form of a film from the hole 2 into the third chamber 6, spraying on the edge of the partition 3. Moreover, the mixture is leaner in the volume of the first chamber 4 and the velocities in it are sufficiently small, which creates favorable conditions for ignition and burnout with high temperature from an electric spark of a candle 8.

From the second chamber 5, hot combustion products enter the third chamber 6, where they are mixed with the mixture coming from the first chamber 4. When mixing, individual moles of the mixture are ignited and the active products of incomplete combustion are released. All this mixture, consisting of hot gases, burning moles of fuel and active products of incomplete combustion, through the pipe 9 enters the flame tube of the combustion chamber (not shown in the drawing), providing active ignition and starting of the combustion chamber.

To increase the yield of active products and improve the conditions for igniting the mixture, oxygen can be supplied to the second chamber 5 through additional openings 12. In this case, when working with oxygen (oxidizing agent), the openings 13 and 14 are plugged. The volume of the third chamber 6 is selected from the condition of ensuring the residence time of the mixture necessary for its ignition, and is associated with the following relations with the volume V _{1 of the} first chamber 4 and the volume V _{2 of the} second chamber 5:

V ₂ / V ₁ >2;

If it is not possible to use the oxygen supply through the openings 12, an air supply from the annular channel of the combustion chamber through the openings 13 and 14 should be applied. The air entering through the openings 13 and 14 forms recirculation zones and improves mixture formation. In this case, the characteristics of the igniter are slightly worse than when the oxidizing agent was supplied through the openings 12. Joint supply of the oxidizing agent through the openings 12 and air through the openings 13 and 14 is not allowed.

Claims (3)

1. The igniter of the combustion chamber, comprising a cylindrical body with an opening for air supply and an internal cavity with a partition and three chambers, in the first of which is an electric candle, in the second - a fuel nozzle, and the third is in communication with the first two and with a radial outlet pipe, this hole for supplying air is made in the wall of the housing between the nozzle of the nozzle and the baffle, in the latter there is a hole communicating the first chamber with the second, the volume of the second chamber is more than twice the volume of the first th camera, and the ratio of the volume of the third camera to the sum of the volumes of the first two cameras is less than two and more than 1/2. 2. The ignitor according to claim 1, characterized in that in the wall of the housing in the second chamber there are additional openings for supplying an oxidizing agent. 3. Igniter according to any one of claims 1 and 2, characterized in that in the wall of the third chamber housing around the radial nozzle, holes are arranged on the same circumference with different diameters through one, and the ratio of the total area of one hole to another is 2 ÷ 2.5 and the ratio of the passage area of the radial outlet pipe to the total area of these holes is 8 ÷ 9.