CN109790752B - Device for introducing an additional mass flow into a main mass flow - Google Patents

Abstract

The invention relates to a device (1) for introducing an additional mass flow into a main mass flow, wherein the main mass flow flows along an axis of rotation, wherein the feed line and the axis of rotation are formed obliquely to each other.

Description

Device for introducing additional mass flow into the main mass flow

technical field

The invention relates to a device for introducing an additional mass flow into a main mass flow, the device having a rotor mounted rotatably about an axis of rotation on which turbine rotor blades are arranged in the circumferential direction, A plurality of rotor blade rows, which are formed one after the other in the direction of rotation, are arranged therein, and the device furthermore has a housing arranged around the rotor.

Background technique

A steam power plant generally includes at least one steam generator and a steam turbine, which is fed with fresh steam from the steam generator. In this case, the steam from the steam generator flows via the live steam line into the live steam inlet of the steam turbine. Control valves and regulating valves are usually provided in the live steam line. The control valve regulates the steam mass flow in the steam line. A quick shut-off valve closes the steam delivery to the steam turbine, which may be necessary, for example, in a fault situation.

There are operating modes of steam turbines which require the introduction of an additional mass flow into the steam turbine. This additional mass flow can be used to increase power. With this additional infeed, further steam can be introduced into the region downstream of the first vane. However, undesired hydromechanical processes can then occur at this load point. The additional mass flow interferes with the main mass flow when entering the steam turbine, which is lost due to mixing of the main and additional mass flow. Furthermore, the main mass flow is deflected by the additional mass flow, which can cause the blade set to not be optimally flown against the flow.

Furthermore, the piping guides of the steam lines of the additional mass flow can disadvantageously be designed in such a way that disturbances in the upstream piping system propagate downstream and thus the additional feed of steam into the steam turbine causes the propagation of disturbances.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a device by means of which the additional mass flow can be better mixed with the main mass flow.

This object is achieved by a device for introducing an additional mass flow into the main mass flow, the device having a rotor mounted rotatably about an axis of rotation, on which turbine rotor blades are arranged in the circumferential direction , wherein a plurality of rotor blade rows are arranged one after the other in the direction of rotation, the device also has a housing arranged around the rotor, wherein a slot is arranged in the housing between the two blade rows, wherein the slot is connected to the rotor. The feed line is connected in a fluid manner, wherein the feed line and the axis of rotation form an angle α with respect to each other, wherein it applies that α≤90°, wherein the groove has an outer groove wall inclined relative to the axis of rotation, the outer The trough wall is downstream with respect to the flow direction, wherein the trough has an inner trough wall inclined with respect to the axis of rotation, the inner trough wall is upstream with respect to the flow direction, wherein the blades of the blade row are arranged upstream of the inner trough wall Having a vane length L, wherein the outer slot wall has a length H, and wherein the inner slot wall has a length Z, where it applies: 0.3*L≤H≤1.5*L.

Advantageous refinements are described in the subsequent description.

The features of the embodiments can be combined with each other in any manner.

In another advantageous development, the feed line is a drilled hole with a diameter D, wherein the distance between the outer wall and the inner wall is B, where the following applies: D≤B≤2*D.

In another advantageous development, the outer wall and the bore are arranged at an angle β with respect to each other, wherein the following applies: −60°<β<60°.

In another advantageous development, an edge with a length Y is formed between the outer wall and the bore.

In another advantageous development, the edge is formed perpendicular to the drilling axis of the drilling.

In another advantageous development, the edge is inclined by ±60° with respect to the vertical of the borehole axis of the borehole.

In another advantageous development, the inner wall and the borehole are arranged at an angle γ with respect to each other, wherein the following applies: −90°<γ<90°.

In another advantageous development, the outer wall is at a distance E from the downstream blade row, where 0<E<0.5*L applies.

In another advantageous refinement, the distance of the inner wall from the upstream blade row is F, where the following applies: 0<F<0.5*L.

The above-described characteristics, features, and advantages of the present invention, and the manner in which they are achieved, will become clearer and more easily understood in conjunction with the following description of the embodiments, which are described in greater detail in conjunction with the accompanying drawings. elaborate.

Description of drawings

Embodiments of the present invention are described next with reference to the accompanying drawings. The figures do not show embodiments to scale, rather the figures for illustration are illustrated in schematic and/or slightly distorted form.

For supplements to the teachings directly visible in the drawings, see the relevant prior art.

The attached figure shows:

Figure 1 shows a schematic diagram of the device.

Detailed ways

Figure 1 shows a schematic view of a device for introducing an additional mass flow into the main mass flow.

The device 1 also comprises a rotor (not shown) rotatably supported about an axis of rotation (not shown) on which turbine rotor blades are arranged in the circumferential direction. The flow direction 2 of the main mass flow is shown in FIG. 1 . Downstream in the flow direction 2, a vane 3 is shown symbolically. Upstream in the flow direction 2, another vane 4 is shown symbolically. These blades 3 and 4 can be rotor blades or guide blades and are arranged on the surface in the circumferential direction of the rotor, wherein a plurality of rotor blade rows are arranged one after the other in the direction of the axis of rotation 5 . The device 1 serves to mix the additional mass flow 6 with the main mass flow 7 . The device 1 is configured to enter a bore hole 8 in the casing of a steam turbine (not shown). The bore 8 opens into a groove 9 provided in the housing. The groove 9 comprises an outer wall 10 which delimits the groove 9 downstream along the flow direction 2 . Furthermore, the groove 9 has an inner wall 11 which is arranged upstream with respect to the flow direction 2 and delimits the groove 9 in the upstream direction. The edge 12 delimits the groove 9 towards the bore hole 8 . The additional mass flow 6 flows through the borehole 8 and is mixed with the main mass flow 7 . The borehole 8 is formed along the borehole direction 12 and is oriented at an angle α with respect to the flow direction 2 or the main mass flow 7 . The value α can have a value between 0° and 90°. The length L is the channel height of the adjoining guide vanes or rotor blades. The inner wall 11 has a length Z. The outer wall 10 has a length H. The applicable ones are: 0.3*L≤H≤1.5*L.

The bore 8 has a diameter D. The distance between the outer wall 10 and the inner wall 11 is B. The applicable ones are: D≤B≤2*D.

The outer wall 10 and the bore 8 are arranged at an angle β with respect to each other. Applicable: -60°<β<60°.

In Figure 1, this relationship is shown schematically by a circular enlargement (upper left of Figure 1). The edge 12 has a length Y. The edge 12 is oriented perpendicular to the drilling direction 13 of the drilled hole 8 . The edge 12 can also be formed obliquely, as is shown in the upper left circular section in FIG. 1 . The reference numeral 14 shows a vertical line with respect to the drilling direction 13 . The edge 12 is inclined at an angle δ relative to the vertical 14 . The angle δ can take values between -60° and 60°.

In FIG. 1, the relationship between the bore hole 8 and the inner wall 11 is shown in the upper right circular portion. The inner wall 11 can be formed obliquely with respect to the bore hole 8 . An angle γ is formed between the bore hole 8 and the inner wall 11 . The angle γ can take values between -90° and 90°. The outer wall 10 is at a distance E from the downstream row of rotor blades (formed by the blades 3). The applicable ones are: 0<E<L. In an alternative embodiment it applies: 0<E<0.5*L.

The distance F of the inner wall 11 from the upstream row of rotor blades 4 is F. The applicable ones are: 0<F<L. In an alternative embodiment, it applies: 0<F<0.5*L.

With the aid of the present invention, the object of delivering the additional mass flow to the main mass flow particularly slowly is pursued. The bore 8 is designed in this case in such a way that the additional mass flow flows into the blade path with minimal velocity. However, for manufacturing reasons, the maximum drill size is limited. Therefore, a circumferential groove 9 is introduced in the housing. The slot 9 has a height which is 30% to 150% of the height L of the blade located downstream thereof. Furthermore, the grooves extend in a direction perpendicular to the drilling direction 13 for one to two drilling diameters. The side of the groove 9 oriented outward on the downstream side runs parallel to the drilling direction 13 or is inclined up to ±60°. The side Z oriented upstream and outward is likewise either parallel to the drilling axis or inclined to the drilling direction 13 by up to ±90°. The side Y either extends perpendicular to the drilling direction 13 or is inclined by ±60° relative to the vertical 14 to the drilling direction 13 within one revolution. In this case, the borehole 8 can likewise be inclined radially or to the greatest extent possible in order to improve the introduction of the steam in the direction of the main mass flow. The angle α is in this case less than 90°. The distances upstream and downstream of the slot 9 from the adjacent vanes 3 and 4 have a length of 0% to 50% of the vane height L.

The hydromechanical effect is exploited by the surrounding grooves 9 . By making the groove 9 wider than the bore hole 8, the groove 9 acts as a Stoβ diffuser. This slows down the flow velocity when mixing the two streams. This is accompanied by smaller losses and less disturbance of the main mass flow. Furthermore, mixing in the circumferential direction takes place inside the groove 9 when leaving the bore hole 8 . This also causes an interaction of the two steam flows, which are thereby reduced. By the way the slot 9 is located between the vanes 3, 4 and the bore hole 8, viewed in the radial direction, the slot acts as a damping when these two flows merge, again with smaller losses and a smaller flow of the main flow interference.

Although the invention is illustrated and described in more detail by preferred embodiments, the invention is not limited to the disclosed examples, and those skilled in the art can deduce other variants therefrom without departing from the scope of protection of the invention .

Claims (9)

1. A device (1) for introducing an additional mass flow into a main mass flow, said device having a rotor mounted rotatably about an axis of rotation on which turbine rotor blades are arranged in circumferential direction , A plurality of rotor blade rows formed in succession along the rotation axis direction (5) are arranged therein, The device also has a housing disposed around the rotor, Wherein a slot (9) is provided in the housing between the two rotor blade rows, wherein the feed line is formed as a bore hole (8) in the housing and leads into the slot (9), wherein the groove is wider than the bore hole, and the groove (9) comprises an outer wall (10) and an inner wall (11), wherein the groove (9) is fluidly connected to the input pipeline, wherein the input line and the axis of rotation form an angle α with each other, Where applicable: α<90°, wherein the groove (9) has an outer groove wall inclined with respect to the axis of rotation, the outer groove wall being located downstream with respect to the flow direction, wherein said groove (9) has an inner groove wall inclined relative to the axis of rotation, said inner groove wall being located upstream with respect to the flow direction, wherein the vanes (3, 4) of the vane row arranged upstream of the inner groove wall have a vane length L, wherein the outer groove wall has a length H, wherein the inner groove wall has a length Z, The following applies: 0.3*L≦H≦1.5*L, wherein an edge ( 12 ) with a length Y is formed between the outer wall ( 10 ) and the bore hole ( 8 ). 2. The device (1) according to claim 1, Wherein the outer wall (10) and the bore hole (8) are arranged at an angle β with respect to each other, wherein it applies: -60°<β<60°. 3. The device (1) according to claim 1, The edge (12) is formed perpendicular to the drilling axis of the drilling hole (8). 4. The device (1) according to claim 1, The edge (12) is inclined by ±60° with respect to the vertical of the drilling axis of the drilling hole (8). 5. The device according to any one of claims 1 to 4, Wherein the inner wall ( 11 ) and the bore hole ( 8 ) are arranged at an angle γ relative to each other, where it applies: −90°<γ<90°. 6. The device of any one of claims 1 to 4, Wherein the distance of the outer wall (10) from the downstream row of rotor blades is E, where it applies: 0<E<L. 7. The device according to any one of claims 1 to 4, Wherein the distance of the outer wall (10) from the downstream row of rotor blades is E, where applicable: 0<E<0.5*L. 8. The device of any one of claims 1 to 4, Wherein the distance of the inner wall (11) from the upstream row of rotor blades is F, where applicable: 0<F<L. 9. The device of any one of claims 1 to 4, Wherein the distance of the inner wall (11) from the upstream rotor blade row is F, where applicable: 0<F<0.5*L.

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