CN113266436B - Channel structure for cooling inside of gas turbine stationary blade and gas turbine stationary blade - Google Patents

Abstract

The invention belongs to the field of gas turbines, and discloses a channel structure for cooling the interior of a gas turbine stator and a gas turbine stator, comprising a plurality of straight channels and a plurality of curved channels; the plurality of straight channels are arranged in parallel, and two adjacent straight channels are connected by the curved channels; It is defined that the wall surface located on the upper side of the main flow direction in the straight channel is the suction surface; the wall surface located on the lower side of the main flow direction is the pressure surface; the suction surface and the pressure surface are provided with a number of inclined ribs; the wall surface connected to the downstream end of the inclined rib in the straight channel A number of transverse ribs are arranged on it, and the downstream end of the inclined rib is the end located downstream in the projection of the inclined rib on the main flow direction; one end of the transverse rib is connected to the inclined rib on the suction surface, and the other end is connected to the pressure surface. Oblique ribs. It can effectively improve the heat transfer in the low Reynolds number area downstream of the fins, make the temperature distribution more uniform, eliminate the local hot spot of the gas turbine stator, improve the thermal stress, improve the stability of the gas turbine stator and prolong the service life.

Description

Channel structure for cooling inside gas turbine stator and gas turbine stator

technical field

The invention belongs to the field of gas turbines, and relates to a channel structure for cooling inside a gas turbine stator and a gas turbine stator.

Background technique

Gas turbine is a kind of power equipment with high cycle efficiency, compact structure, small size, light weight and large output power. It is widely used in important industrial fields such as aviation power, ship propulsion, and land power generation. important position in the civil field.

Studies have shown that increasing the inlet temperature of the gas turbine is an effective way to improve the cycle efficiency and output power of the gas turbine. When the gas inlet temperature increases by 100℃, the cycle specific work can be increased by 20-25%, and the fuel consumption can be reduced by 6-7%. At present, with the continuous development of gas turbine technology, the turbine inlet temperature continues to increase. For land-use heavy-duty gas turbines, the turbine inlet temperature has developed from 1200-1400 °C in the B/E/F grade to the G/H/J grade. At 1600 °C, the corresponding single cycle efficiency increased from 32% to 34% to 42%, and the combined cycle efficiency increased from 48% to 52% to 61%. In order to obtain higher heat-to-power conversion efficiency and output power, more advanced heavy-duty gas turbines with a turbine inlet temperature of 1700 °C are also being developed.

However, with the increase of the inlet temperature of the gas turbine turbine, it has far exceeded the allowable temperature of the metal material of the turbine blade. Under the erosion of the high-temperature gas, a large thermal stress will be generated, which will not only reduce the The mechanical properties of the gas turbine are not high, and the blades are easily burned, which seriously affects the economy and safety of the gas turbine operation. Therefore, gas turbine blade cooling technology is crucial.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art that, with the increase of the inlet temperature of the gas turbine turbine, the thermal stress of the gas turbine blades increases, which reduces the performance of the blades or even damages the blades, and provides a cooling system for the internal cooling of the gas turbine stator blades. The channel structure and gas turbine stator blades.

To achieve the above object, the present invention adopts the following technical solutions to realize:

In one aspect of the present invention, a channel structure for cooling inside a stator blade of a gas turbine includes a plurality of straight channels and a plurality of curved channels;

Several straight channels are arranged in parallel, and two adjacent straight channels are connected by curved channels;

Define the wall surface on the upper side of the main flow direction in the straight channel as the suction surface; the wall surface on the lower side of the main flow direction is the pressure surface; several inclined ribs are arranged on the suction surface and the pressure surface;

A number of transverse ribs are arranged on the wall connected to the downstream end of the inclined rib in the straight channel, and the downstream end of the inclined rib is the downstream end of the inclined rib in the projection of the main flow direction; one end of the transverse rib is connected to the suction surface The inclined rib is connected to the other end of the inclined rib on the pressure surface.

The further improvement of the channel structure used for cooling the interior of the gas turbine stator blades of the present invention is:

The angle between the inclined ribs and the main flow direction is 30°˜150°.

The aspect ratio of the straight channel is 0.25˜2.

The heights of the oblique ribs and the transverse ribs are 1-3 mm.

Several oblique ribs on the suction surface and the pressure surface are evenly distributed, and the spacing between adjacent oblique ribs is 10-20 mm.

The suction surface and the pressure surface are curved surfaces, respectively consistent with the curvature of the two outer wall surfaces of the gas turbine stator blade.

Both the suction surface and the pressure surface are provided with through ribs along the main flow direction, and the through ribs pass through several inclined ribs on the suction surface or the pressure surface in sequence.

A plurality of transverse micro-tooths are arranged on both the inclined ribs and the transverse ribs along the main flow direction.

The number of the straight channels is three.

A second aspect of the present invention provides a gas turbine stator blade, wherein the above-mentioned channel structure for cooling the inside of the gas turbine stator blade is arranged inside the gas turbine stator blade.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention is used for the channel structure for cooling inside the stator blade of the gas turbine. By arranging several oblique ribs on the suction surface and the pressure surface, and setting several transverse ribs on the wall surface connected with the downstream end of the oblique ribs in the straight channel, when cooling After the working fluid enters the channel, the separation of the boundary layer will occur at the top of the fins of the inclined ribs and reattach in the downstream inter-rib area, thereby generating a longitudinal secondary flow. The longitudinal secondary flow will develop along the direction of the fins and merge with the main secondary flow at the downstream end of the fins. Due to the existence of transverse ribs on the sidewall surface, the boundary layer along the sidewall surface will also separate and reattach at the transverse ribs. As a result, the boundary layer of the sidewall surface is continuously damaged and difficult to develop and thicken, thereby strengthening the mixing of the cooling medium in the channel, increasing the temperature gradient of the cooling medium near the wall surface, and effectively improving the low Reynolds number region downstream of the fins. The heat transfer of the gas turbine makes the temperature distribution more uniform, achieves a better cooling effect, eliminates the local hot spot on the gas turbine stator, improves the thermal stress, improves the stability of the gas turbine stator, and prolongs the gas turbine stator blade. service life.

Further, the suction surface and the pressure surface are curved surfaces, which are respectively consistent with the curvature of the two outer wall surfaces of the gas turbine stator. Heat transfer area and reduce flow loss, ultimately improve heat transfer effect.

Further, the suction surface and the pressure surface are provided with through ribs along the main flow direction, and the through ribs pass through several inclined ribs on the suction surface or the pressure surface in turn. By setting the through ribs, the heat exchange of the channel structure is more uniform and effective. Reduce flow losses.

Further, a plurality of transverse micro-tooths are arranged on both the oblique ribs and the transverse ribs along the main flow direction. By setting the micro-tooth, it helps to strengthen the longitudinal secondary flow of the cooling medium, thereby improving the heat exchange capacity.

Description of drawings

1 is a schematic diagram of a channel structure used for cooling inside a gas turbine stator blade in an embodiment of the present invention;

2 is a top view of a channel structure used for cooling inside a gas turbine stator blade in an embodiment of the present invention;

3 is a schematic diagram of the angle between the inclined rib and the main flow direction of the present invention;

4 is a schematic structural diagram of another channel for cooling the interior of a gas turbine stator blade in an embodiment of the present invention;

Fig. 5 is the temperature distribution cloud diagram of the existing channel structure used for cooling inside the gas turbine stator blade;

FIG. 6 is a temperature distribution cloud diagram of a channel structure used for cooling inside a gas turbine stator blade according to the present invention.

Among them: 1-straight channel; 2-curved channel; 3-oblique rib; 4-transverse rib; 5-through rib.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only Embodiments are part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first", "second" and the like in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used may be interchanged under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having" and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

Below in conjunction with accompanying drawing, the present invention is described in further detail:

Referring to FIGS. 1 to 3 , in an embodiment of the present invention, a channel structure for cooling the interior of a gas turbine stator blade is provided, which can effectively improve the heat transfer in the low Reynolds number area downstream of the fins, make the temperature distribution more uniform, and eliminate the static electricity of the gas turbine. The local hot spot of the blade improves the thermal stress, improves the stability of the gas turbine stator blade, and prolongs the service life of the gas turbine stator blade.

Specifically, the channel structure for cooling the interior of the gas turbine stator includes several straight channels 1 and several curved channels 2; several straight channels 1 are arranged in parallel, and two adjacent straight channels 1 are connected by the curved channel 2; The wall surface on the upper side of the main flow direction is the suction surface; the wall surface located on the lower side of the main flow direction is the pressure surface; the suction surface and the pressure surface are provided with a number of inclined ribs 3; the wall surface connected with the downstream end of the inclined ribs 3 in the straight channel 1 A number of transverse ribs 4 are arranged on the upper part, and the downstream end of the inclined rib 3 is the end located downstream in the projection of the inclined rib 3 on the main flow direction; one end of the transverse rib 4 is connected to the inclined rib 3 on the suction surface, and the other end is Connect the inclined ribs 3 on the pressure surface. Among them, the main flow direction is the direction from the inlet to the outlet of the entire channel structure, and the cooling medium generally adopts compressed cold air.

In this embodiment, three straight channels 1 and two curved channels 2 are provided, and the three straight channels 1 are arranged in parallel and are connected by two curved channels 2 to form an s-shaped three-flow channel.

During specific operation, after the cooling medium enters the channel, the boundary layer will be separated at the top of the fins of the inclined ribs 3, and will be reattached in the downstream inter-rib area, thereby generating a longitudinal secondary flow. The longitudinal secondary flow will develop along the direction of the fins and merge with the main secondary flow at the downstream end of the fins. Due to the existence of the transverse ribs 4 on the side wall surface, the boundary layer along the side wall surface will also produce separation and separation at the transverse rib 4. The phenomenon of re-attachment leads to the continuous damage of the boundary layer of the side wall, which is difficult to develop and thicken, thereby strengthening the mixing of the cooling medium in the channel, increasing the temperature gradient of the cooling medium near the wall, and effectively improving the heat transfer downstream of the fins. Mass transfer makes the temperature distribution more uniform, achieves better cooling effect, eliminates local hot spots on gas turbine stator blades, improves thermal stress, improves the stability of gas turbine stator blades, and prolongs the use of gas turbine stator blades. life.

Preferably, the angle α between the inclined ribs 3 and the main flow direction is 30°˜150°, and preferably, the angle α between the inclined ribs 3 and the main flow direction is 60°.

Preferably, the aspect ratio of the straight channel 1 is 0.25˜2, and preferably, the aspect ratio of the straight channel 1 is 1.

Preferably, the heights of the oblique ribs 3 and the transverse ribs 4 are 1-3 mm, and preferably, the heights of the oblique ribs 3 and the transverse ribs 4 are 2 mm.

Preferably, the several inclined ribs 3 on the suction surface and the pressure surface are evenly distributed, and the spacing between adjacent inclined ribs 3 is 10-20 mm. Preferably, the spacing between adjacent inclined ribs 3 is 16mm.

Preferably, the suction surface and the pressure surface are curved surfaces, respectively consistent with the curvature of the two outer wall surfaces of the gas turbine stator blade. By setting the suction surface and the pressure surface as curved surfaces consistent with the curvature of the two outer wall surfaces of the gas turbine stator blade, the heat exchange area is effectively increased, the flow loss is reduced, and the heat exchange effect is finally improved.

Preferably, referring to FIG. 4 , both the suction surface and the pressure surface are provided with through ribs 5 along the main flow direction, and the through ribs 5 pass through several inclined ribs 3 on the suction surface or the pressure surface in sequence. By arranging the through ribs 5, the heat exchange of the channel structure is more uniform, and the flow loss is effectively reduced.

Preferably, the inclined ribs 3 and the transverse ribs 4 are provided with a plurality of transverse micro teeth along the main flow direction. Wherein, the width of the micro teeth is 0.87mm, the height is 0.5mm, and the distance between adjacent micro teeth is 0.87mm. By arranging micro teeth on the rib surfaces of the inclined ribs 3 and the transverse ribs 4, it is helpful to strengthen the longitudinal secondary flow of the cooling medium and improve the heat exchange capacity.

Referring to Figures 5 and 6, it shows the simulation schematic diagram of the cooling effect of the existing channel structure used for cooling inside the gas turbine stator and the channel structure used for cooling the inside of the gas turbine stator according to the present invention. In this embodiment, the present invention is used for the gas turbine. In the channel structure for cooling inside the stator, the angle between the oblique ribs 3 and the main flow direction is 60°, the aspect ratio of the straight channel 1 is 1, the height of the oblique ribs 3 and the transverse ribs 4 is 2 mm, and the adjacent oblique ribs 3 and 4 have a height of 2 mm. The spacing between the ribs 3 is 16mm.

It can be seen from the figure that the lighter the color, the higher the surface temperature. The existing channel structure used for cooling the interior of the gas turbine stator has obvious high temperature areas downstream of the fins of the three channels, and the temperature is high, close to the gas turbine. Mainstream working fluid temperature. Such a high temperature area will generate large thermal stress, which will not only reduce the mechanical properties of the metal blades, but also easily cause the blades to burn, thus seriously affecting the economy and safety of gas turbine operation. The channel structure used for cooling the interior of the gas turbine stator can greatly reduce the area of the high temperature area downstream of the fins, and the area of the high temperature area can be reduced by more than 50% at the front and middle of the three channels. It is worth noting that the boundary conditions and working fluid inlet parameters used in the two simulations are exactly the same. Due to the limited cooling effect of the existing channel structure used for cooling the interior of the gas turbine stator blade and the large area of the high temperature area, the heat absorption of the working medium is less than that of the channel structure used for cooling the interior of the gas turbine stator blade according to the present invention. The temperature of the working fluid is lower than that of the present invention, so the area reduction effect of the high temperature area is not obvious near the outlet of the channel. The cooling effect of the channel structure for cooling inside the stator vanes of the gas turbine is obviously better than that of the existing structure.

It can be seen from the above that, compared with the existing channel structure for cooling the interior of gas turbine stator blades, the channel structure of the present invention can significantly reduce the area of high-temperature hot spots, eliminate some hot spots, and reduce heat Stress, improve the mechanical properties of the metal blade, and increase the area of the low temperature area, so that the wall temperature distribution is more uniform, and the heat transfer effect is strengthened.

In an embodiment of the present invention, a gas turbine stator blade is provided, and the above-mentioned channel structure for cooling the inside of the gas turbine stator blade is arranged inside the gas turbine stator blade. The gas turbine stator blade of the present invention realizes the internal cooling of the gas turbine stator blade by digging the channel structure of the present invention for cooling the interior of the gas turbine stator blade in the existing gas turbine stator blade.

The above content is only to illustrate the technical idea of the present invention, and cannot limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention all fall within the scope of the claims of the present invention. within the scope of protection.

Claims (4)

1. A channel structure for cooling the inside of a stationary blade of a gas turbine is characterized by comprising a plurality of straight channels (1) and a plurality of curved channels (2);

a plurality of straight channels (1) are arranged in parallel, and two adjacent straight channels (1) are connected through a bent channel (2);

defining the wall surface at the upper side of the main flow direction in the straight channel (1) as a suction surface; the wall surface positioned at the lower side of the main flow direction is a pressure surface; the suction surface and the pressure surface are both provided with a plurality of inclined ribs (3);

a plurality of transverse ribs (4) are arranged on the wall surface connected with the downstream ends of the inclined ribs (3) in the straight channel (1), and the downstream ends of the inclined ribs (3) are the downstream ends of the inclined ribs (3) in the projection of the inclined ribs (3) in the main flow direction; one end of the transverse rib (4) is connected with the inclined rib (3) on the suction surface, and the other end is connected with the inclined rib (3) on the pressure surface;

the included angle between the inclined rib (3) and the main flow direction is 30-150 degrees;

the width-to-height ratio of the straight channel (1) is 0.25-2;

the height of the inclined ribs (3) and the transverse ribs (4) is 1-3 mm;

the inclined ribs (3) on the suction surface and the pressure surface are uniformly distributed, and the distance between every two adjacent inclined ribs (3) is 10-20 mm;

the suction surface and the pressure surface are both provided with penetrating ribs (5) along the main flow direction, and the penetrating ribs (5) sequentially penetrate through a plurality of obliquely arranged ribs (3) on the suction surface or the pressure surface;

a plurality of transverse micro-teeth are arranged on the inclined ribs (3) and the transverse ribs (4) along the main flow direction.

2. The channel structure for internal cooling of a gas turbine vane as claimed in claim 1, wherein the suction surface and the pressure surface are curved surfaces respectively conforming to the curvature of both outer wall surfaces of the gas turbine vane.

3. Channel structure for the internal cooling of gas turbine vanes according to claim 1, characterised in that the number of straight channels (1) is 3.

4. A gas turbine stationary blade characterized in that the passage structure for internal cooling of a gas turbine stationary blade according to any one of claims 1 to 3 is provided inside the gas turbine stationary blade.

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