EP1473517A1 - Combustion chamber - Google Patents

Abstract

A combustion chamber (4) for a gas turbine (1), the combustion chamber wall (24) of which is provided on the inside with a lining formed by a number of heat shield elements (26), should be designed for particularly high operational safety. According to the invention, there is one or a number of temperature sensors (28) between the combustion chamber wall (24) and the heat shield elements (26). <IMAGE>

Description

The invention relates to a combustion chamber for a gas turbine, whose combustion chamber wall on the inside with one of a Number of liners formed by heat shield elements is provided. The invention further relates to a gas turbine with such a combustion chamber.

Combustion chambers are u. A. Part of gas turbines, which in many areas for driving generators or work machines be used. Thereby the energy content a fuel to produce a rotational movement a turbine shaft. The fuel is used by Burners burned in the downstream combustion chambers, compressed air supplied by an air compressor becomes.

A separate combustion chamber can be assigned to each burner be, the working medium flowing out of the combustion chambers be brought together before or in the turbine unit can. Alternatively, the combustion chamber can also be used in such a way mentioned annular combustion chamber design, in which a plurality, especially all, of the burners in a common, usually annular combustion chamber open.

The combustion of the fuel turns it into a low Pressurized working medium generated at a high temperature. This working medium relaxes in the combustion chambers downstream turbine unit performing work. To the turbine unit has a number of with the turbine shaft connected, rotatable blades. The blades are arranged in a ring on the turbine shaft and thus form a number of rows of blades. Farther the turbine includes a number of fixed vanes, which is also ring-shaped with the formation of Guide vane rows attached to an inner casing of the turbine are. The blades serve to drive the Turbine shaft by momentum transfer from the turbine flowing through Working medium. The guide vanes, however, are used for Flow of the working medium between two in each Direction of flow of the working medium seen consecutive Blade rows or blade rings. A successive Pair from a wreath of guide vanes or a row of guide vanes and one in the direction of flow of the working medium downstream of rotor blades or a row of moving blades forms a turbine stage.

When designing such gas turbines in addition to achievable performance usually a particularly high efficiency a design goal. An increase in efficiency can basically be used for thermodynamic reasons by increasing the outlet temperature, with which the working medium from the combustion chamber and into the Turbine unit flows. Therefore temperatures of around Desired 1200 ° C to 1500 ° C for such gas turbines and also achieved.

At such high temperatures of the working medium, however the components and parts exposed to this medium exposed to high thermal loads. To still at high Reliability a comparatively long lifespan It is usually necessary to ensure the affected components a design with particularly heat-resistant materials and cooling the affected components, in particular the combustion chamber, necessary.

The combustion chamber wall is usually on the inside with an inner lining consisting of heat shield elements provided with particularly heat-resistant Protective layers can be provided, and by the actual Cooling the combustion chamber wall. This will usually a cooling process also referred to as "impact cooling" used. Impact cooling uses a coolant, usually cooling air, through a number of holes supplied to the heat shield elements in the combustion chamber wall, so that the coolant is substantially perpendicular to their the The outer surface facing the combustion chamber wall bounces. The coolant heated by the cooling process is then from the interior, the combustion chamber wall with the heat shield elements forms, dissipated.

To attach the heat shield elements to the combustion chamber wall on the one hand there is the possibility of using screws or connecting bolts to the combustion chamber wall. Alternatively, heat shield elements can be attached using appropriate brackets also on grooves in the combustion chamber wall, to be anchored to this.

The problem with operating a gas turbine is that Heat shield elements or sections of these from the Can solve the combustion chamber wall. This usually happens because the heat shield elements or their fasteners due to the extreme influences in the combustion chamber interior, such as the high thermal loads or shocks and vibrations the combustion chamber. This from the combustion chamber wall loosened parts pass through the flow movement of the working medium in the turbine unit, where they run and Can destroy guide vanes. With such a loss of heat shield element detached heat shield elements or parts of it, however, not in the turbine unit, since they in front of the first row of guide vanes of the first turbine stage accumulate or wedge in front of or in the guide vanes. The presence of heat shield elements or parts thereof leads in front of the turbine unit during operation of the gas turbine to flow and pressure fluctuations in the form of flow turbulence in the turbine unit. These turmoil are in usually so strong that blades like the one in particular Tear off blades of the first turbine stage and thus large parts of the turbine unit, like the neighboring ones and subsequent rows of guide vanes and blades. As a rule, in the event of a loss of the heat shield, it passes between loosening a heat shield element on the Combustion chamber wall and the first tearing of blades, caused by turbulence due to jammed heat shield elements triggered a few minutes. If the Turbine unit in addition to the repair costs fall in particular production downtimes of the gas turbine, so that very high total costs may arise.

The invention is therefore based on the object of a combustion chamber of the type mentioned above, in which a particular high operational security can be achieved.

With regard to the combustion chamber, this object is achieved according to the invention solved by between the combustion chamber wall and heat shield elements one or a number of temperature sensors arranged are.

The invention is based on the consideration that for a guarantee of a high level of operational security for the Combustion chamber a destruction of the turbine by itself Heat shield elements must be avoided. Therefore, the Gas turbine in time in the event of loss of heat shield element can be switched off if a heat shield element comes loose. To do this, the loss of a heat shield element on the The combustion chamber wall can be registered in good time. On special the simple way is the loss of a heat shield element due to the temperature change occurring on the combustion chamber wall detectable. When a heat shield is removed the otherwise cooled space becomes the combustion chamber wall between the combustion chamber wall and the heat shield element due to the lack of thermal insulation to the combustion chamber interior comparatively heat up quickly and strongly or the combustion chamber wall almost in the area of missing inner wall lining adjust to the temperatures in the combustion chamber interior. This temperature difference that occurs when a heat shield element is detached can occur with temperature-dependent sensors, where the temperature dependence is especially about given the electrical resistance or the melting behavior is measured and thus indirectly the absence of a heat shield element can be detected.

To use multiple heat shield elements with a temperature sensor Combustion chamber lining at the same time for completeness or to monitor for a possible absence a temperature sensor advantageously as one along one Component stretched direction. To this This can be positioned along the combustion chamber wall and all heat shield elements that are between Monitor the temperature sensor and the combustion chamber interior. Overall, this is also a particularly simple construction reachable.

To fix a temperature sensor on the combustion chamber wall and to lead along this is conveniently in an associated groove in the circumferential direction of the Combustion chamber wall.

To the temperature change on the combustion chamber wall in the event of loss to reliably detect a heat shield element, different versions are conceivable.

In a first variant, there is preferably a temperature sensor from an electrically conductive fuse wire. In the area a missing heat shield element melts when Exceeding the melting temperature of the wire and destroyed thereby the electrical conductivity. The resulting strong increase in resistance or the open circuit of the fuse wire can in turn be measured and thereby loss of heat shield element Show.

A fuse wire advantageously has a melting temperature between 300 ° C and 1000 ° C, preferably between 500 ° C and 700 ° C. This temperature range is chosen that the melting temperature is between the temperature of the cooled Side of the heat shield elements and the combustion chamber wall in normal operation on the one hand and the much higher temperature the unprotected combustion chamber wall, so that if the heat shield element is lost, the melting temperature comparatively quickly and clearly on the fuse wire is exceeded.

In a second variant, the temperature sensor is advantageously formed from a current-carrying wire, the has a temperature-dependent electrical conductivity, so that it does not in the event of loss of the heat shield element gets destroyed. With a temperature change in the range of Wire changes the temperature dependent resistance of the Wire and with it the current that flows through the wire whereby the loss of a heat shield element is detected leaves.

An active signal for the loss of a heat shield element to use, there is a temperature sensor expediently from a thermocouple. This can be done via a change in thermal voltage a change in temperature and thus a heat shield element loss in the area of Detect thermocouple.

So when using thermocouples for monitoring the heat shield elements with a measuring circuit several heat shield elements the combustion chamber wall lining at the same time for their completeness or for the possible absence of a There is a temperature sensor to monitor the heat shield element preferably from a series connection of Thermocouples. A triggered by an increase in temperature Voltage change of a thermocouple can be by monitoring the total voltage of the series connection monitor because the output voltages of each Add thermocouples due to the series connection.

To build a suitable measuring circuit for monitoring to make the heat shield elements as simple as possible, a temperature sensor expediently consists of a jacket thermocouple. This advantageously consists of two parallel thermal wires that are lengthwise through a material with a positive temperature coefficient from each other are isolated. With a temperature increase on one The place of the endless thermocouple is reduced Resistance in the insulation material of the heated area, so that the thermal voltage between the two thermal wires elevated. The thermal voltage therefore corresponds approximately to that highest temperature in the course of the jacket thermocouple.

To keep the entire combustion chamber open during operation monitor any loss of heat shield elements, sensors are preferably to an assigned evaluation circuit connected, the temperature distribution via the temperature sensors monitors the combustion chamber and thereby the Loss of heat shield elements or parts thereof registered.

The above-mentioned combustion chamber is preferably a component a gas turbine.

Damage caused by loosened heat shield elements or parts to avoid this in the area of the turbine unit of the gas turbine the gas turbine is advantageously via the evaluation circuit can be switched off automatically. In case of detection heat shield element loss from temperature sensors or the downstream evaluation circuit can in particular the combustion chamber as well as the turbine promptly after the loss of the heat shield element be shut down.

The advantages achieved with the invention are in particular in that by positioning temperature sensors between the combustion chamber wall and heat shield elements Combustion chamber loss of a heat shield element or parts these are reliably detectable and cause damage Avoid in the turbine unit downstream of the combustion chamber by the gas turbine in the event of heat shield loss through the downstream of the temperature sensors Evaluation circuit is turned off automatically. The Advantage of using temperature sensors, in particular are formed along a route, that is not each heat shield element individually with a temperature sensor must be provided, but several heat shield elements with a temperature sensor or a measuring circuit can be monitored are. The use of thermocouples and especially one Sheathed thermocouples have good monitoring options of the heat shield elements and easy evaluation of the output signal, the advantage that thermocouples for very high temperatures can be used and are therefore suitable for Recommend heat shield element monitoring on the combustion chamber wall.

FIG 1

einen Halbschnitt durch eine Gasturbine,

FIG 2

die Brennkammer der Gasturbine nach Fig. 1,

FIG 3

einen in Umfangsrichtung der Brennkammer angeordnete Temperatursensor,

FIG 4

einen Ausschnitt aus der Wand der Brennkammer nach Fig. 2, und

FIG 5

einen Schnitt durch ein Mantelthermoelement.

An embodiment is explained in more detail with reference to a drawing. In it show:

FIG. 1

a half-section through a gas turbine,

FIG 2

the combustion chamber of the gas turbine according to FIG. 1,

FIG 3

a temperature sensor arranged in the circumferential direction of the combustion chamber,

FIG 4

a section of the wall of the combustion chamber of FIG. 2, and

FIG 5

a section through a jacket thermocouple.

The same parts have the same reference symbols in all the figures Mistake.

The gas turbine 1 according to FIG. 1 has a compressor 2 for Combustion air, a combustion chamber 4 and a turbine 6 for Drive the compressor 2 and a generator, not shown or a work machine. To do this are the turbine 6 and the compressor 2 on a common, also called Turbine rotor designated turbine shaft 8 arranged with which also connects the generator or the working machine is, and which is rotatably mounted about its central axis 9. The Combustion chamber 4 designed in the manner of an annular combustion chamber is with a number of burners 10 for burning one liquid or gaseous fuel.

The turbine 6 has a number of with the turbine shaft 8 connected, rotatable blades 12. The blades 12 are arranged in a ring shape on the turbine shaft 8 and thus form a number of rows of blades. Farther The turbine 6 comprises a number of fixed guide vanes 14, which is also ring-shaped with the formation of Guide vane rows attached to an inner housing 16 of the turbine 6 are. The blades 12 serve to drive the turbine shaft 8 by transfer of momentum from the turbine 6 working medium flowing through M. The guide vanes 14 serve in contrast to the flow of the working medium M between seen two in the flow direction of the working medium M. successive rows of blades or blade rings. A successive pair from a wreath of Guide vanes 14 or a row of guide vanes and from one Wreath of blades 12 or a row of blades is also referred to as the turbine stage.

Each guide vane 14 has one which is also referred to as a blade root Platform 18, which is used to fix the respective guide vane 14 on the inner housing 16 of the turbine 6 as a wall element is arranged. The platform 18 is a thermal comparison heavily loaded component that the outer boundary a heating gas channel for the one flowing through the turbine 6 Working medium M forms. Each blade 12 is analog Way over a platform 20 also referred to as a blade root attached to the turbine shaft 8.

Between the spaced platforms 18 of the guide vanes 14 of two adjacent rows of guide vanes is a respective guide ring 21 on the inner housing 16 of the Turbine 6 arranged. The outer surface of each guide ring 21 is also hot, flowing through the turbine 6 Working medium M exposed and in the radial direction from the outer end 22 of the blade opposite to it 12 spaced by a gap. The one between neighboring Guide rings 21 arranged guide vane rows serve in particular as cover elements that cover the inner wall 16 or other housing installation parts before a thermal Overuse by the flowing through the turbine 6 protects hot working medium M.

The combustion chamber 4 is so-called in the exemplary embodiment Annular combustion chamber designed in which a variety of in Arranged circumferentially around the turbine shaft 8 Burners 10 open into a common combustion chamber space. To is the combustion chamber 4 in its entirety as an annular Designed structure that positioned around the turbine shaft 8 is.

To achieve a comparatively high efficiency the combustion chamber 4 for a comparatively high temperature of the working medium M from about 1000 ° C to 1600 ° C. This also applies to these operating parameters, which are unfavorable for the materials to enable a comparatively long operating time is the combustion chamber wall 24 on the working medium M facing side with one made of heat shield elements 26 provided inner lining. Any heat shield element 26 is special on the working medium side heat resistant protective layer or made of high temperature resistant Made of material. Because of the high Temperatures inside the combustion chamber 4 is also for the Heat shield elements 26 or a cooling system for their holding elements intended.

The combustion chamber 4 is particularly suitable for the detection of Losses of the heat shield elements 26 designed. To do this between the combustion chamber wall 24 and the heat shield elements 26 positioned a number of temperature sensors 28 which elongated in each case in a groove 30 of the combustion chamber wall 24 run, these the heat shield elements 26 each in Surround the circumferential direction of the combustion chamber 4, as can be seen in FIG. 2 reveals. A temperature increase due to the loss of a heat shield element 26 on the combustion chamber wall 24 To be able to, the temperature sensor 28 optionally consists of a current-carrying fuse wire, one or more Thermocouples or from a jacket thermocouple 31. The Temperature sensor 28 is in particular, as in FIG. 3 schematically shown as in the circumferential direction of the combustion chamber 4th extensive, elongated monitoring element executed.

To clarify the mode of operation of the temperature sensor 28 4 shows a detail of the combustion chamber wall 24. With intact, properly installed heat shield elements 26 these are on the working medium M from Inside the combustion chamber 4 thermally stressed, the isotherm 29, ie the contour of the same temperature, essentially runs parallel to the inner wall. About the thickness of the heat shield element 26 there is a considerable temperature gradient so that's on the cool side of the heat shield elements 26 arranged temperature sensors 28 with only comparatively lower temperature can be applied. However, if a heat shield element 26 is lost should, isotherm 29a arises. In this case the temperature sensor 28 is thus at a significantly elevated temperature acted on, so that depending on the version, for example a significant change in electrical resistance or the electrical conductivity or a melting through Fusible wire can be determined.

A cross-sectional view of this temperature sensor 28 is listed in FIG 5. As can be seen from the figure, sets the jacket thermocouple (31) consists of two arranged in parallel Thermal wires 32 together, which are in a temperature dependent Insulation material 34 and the length after are isolated from each other by this. The materials the thermal wires 32, the temperature coefficient of the insulating mass and the dimensioning of the entire jacket thermocouple are based on the temperature ranges to be measured Combustion chamber wall 24 matched so that there is a loss a heat shield element 24, the electrical resistance in Insulated material 34 of the heated area is reduced and the thermal voltage between the two thermal wires 32 elevated.

To record the loss of heat shield elements 26 centrally To be able to, all temperature sensors 28 are to the evaluation circuit 36 connected. This is especially for this designed in the loss of a heat shield element 26 the Turn off gas turbine 1. For that she is with the Relay control of the gas turbine 1 connected.

Claims (13)

Combustion chamber (4) for a gas turbine (1), the combustion chamber wall (24) on the inside with one of a number of heat shield elements (26) formed lining is provided, wherein between the combustion chamber wall (24) and heat shield elements (26) a number of temperature sensors (28) is arranged. Combustion chamber (4) according to claim 1, whose temperature sensors (28) as a component extended along an extension direction are trained. Combustion chamber (4) according to claim 1 or 2, the temperature sensor (28) in an associated circumferential direction Groove (30) is arranged in the combustion chamber wall (24). Combustion chamber (4) according to one of claims 1 to 3, the Temperature sensors (28) each made of an electrically conductive Fusible wire are formed. Combustion chamber (4) according to claim 4, the respective electrical conductive fuse wire a melting temperature between about 300 ° C and about 1000 ° C. Combustion chamber (4) according to one of claims 1 to 5, in which the or each temperature sensor (28) consists of one current-carrying one Wire is formed which is temperature dependent has electrical conductivity. Combustion chamber (4) according to one of claims 1 to 6, in which at least some of the temperature sensors (28) made of thermocouples are formed. Combustion chamber (4) according to one of claims 1 to 7, in which at least some of the temperature sensors (28) each from one Series connection of thermocouples are composed. Combustion chamber (4) according to one of claims 1 to 8, the Temperature sensors (28) from a jacket thermocouple (31) are formed. Combustion chamber (4) according to claim 9, wherein the or each Sheathed thermocouple (31) consisting of two parallel thermal wires (32) composed by a temperature dependent length Isolating material (34) separated from each other are. Combustion chamber (4) according to any one of claims 1 to 10, the Temperature sensors (28) to an assigned evaluation circuit (36) are connected. Gas turbine (1) with a combustion chamber (4) according to one of the Claims 1 to 11. Gas turbine (1) according to claim 12 in conjunction with claim 11, automatically via the evaluation circuit (36) can be switched off.

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