EP3023593A1 - Inlet contour for single shaft configuration - Google Patents

Abstract

The invention relates to a turbomachine with a Einströmringkanal (3), which is fluidically connected to a Einströmstutzen (9), wherein the Einströmstutzen (9) is designed such that an incoming flow is initially slowed down and then accelerated and simultaneously deflected.

Description

The invention relates to a turbomachine comprising a rotor rotatably mounted about a rotation axis, a housing arranged around the rotor and a flow channel formed between the rotor and the housing, further comprising an inflow region, which has an inlet connection and opens into an inflow channel, wherein the inflow channel in Substantially has an annular channel cross-section and is fluidly connected to the flow channel, wherein the inflow channel is formed about the axis of rotation, wherein the inflow has an inflow cross section through which a flow medium flows in operation in a flow direction.

Furthermore, the invention relates to a method for connecting a Einströmstutzens to a Einströmringkanal.

Turbomachines, such as steam turbines, essentially comprise a rotor mounted rotatably about a rotation axis, which comprises rotor blades, and a housing formed with guide vanes, wherein a flow channel is formed between the rotor and the housing, which comprises the guide vanes and rotor blades. A thermal energy of the steam is converted into a mechanical energy of the rotor. There are various sub-turbines are known, which are classified for example in high-pressure, medium-pressure and / or low-pressure turbine sections. The division of the sub-turbines into a high-pressure, medium-pressure and low-pressure part is not uniformly defined in the art. In any case, the classification depends on the pressure and the temperature of the incoming and outgoing steam.

Furthermore, embodiments are known in which a high-pressure part and a medium-pressure part in a common Outer housing are arranged. Such embodiments require two inflow regions which are arranged close to each other. It is from rotor dynamic aspects required that the high pressure and medium pressure inflow are close to each other, since the axial space is limited. Furthermore, it is less expensive if the high-pressure and medium-pressure inflow regions are arranged close to each other.

Furthermore, it is known to supply the steam via valves to the flow channel. In this case, a steam flows through a Schnellschluss- and a control valve and then into an inflow and from there into an annular channel. The annular channel is formed substantially rotationally symmetrical about the axis of rotation. The velocities of the steam in the annular channel should be as even and as small as possible. In two-valve arrangements, that is, a vapor flows through two valves and thus via two inflow regions into the inflow channel, the flow conditions in the annular channel are different than in one-valve arrangements. In Einventilanordnungen the steam flows through only one inflow into the annular channel. In Einventilanordnungen the cross section of the annular channel is usually greater than the cross section of the annular channel in a two-valve arrangement. This is essentially because the flow rates are kept at a low level.

It would be possible to increase the annular channel in the radial direction, which, however, increases internal pressure driven voltages in the inner housing. On the other hand, an increase in the wall thickness would lead to a voltage reduction, which in turn would lead to an increase in the temperature-driven voltages. These two design concepts need to be optimized.

The invention has set itself the task of specifying an inflow, which leads to improved flow conditions.

This object is achieved by a turbomachine comprising a rotor rotatably mounted about a rotation axis, a housing disposed around the rotor and a flow channel formed between the rotor and the housing, further comprising an inflow portion having an inflow port and opening into an inflow channel, wherein the Inflow ring channel substantially has an annular channel cross-section and is fluidly connected to the flow channel, wherein the inflow channel is formed about the axis of rotation, wherein the inflow has an inflow cross section through which during operation a flow medium flows in a flow direction, wherein the cross section in the flow direction itself enlarged to a maximum cross-section and then reduced to the annular channel cross-section.

The invention thus pursues the approach of changing the flow velocities in the inflow region, which is achieved by a change in geometry of the inflow region. In essence, while the connection of the cross section between the inflow and the annular channel is modified, the cross-section beyond the annular channel cross-section also increases and after the slowing down of the flow a renewed acceleration, but is achieved in a different direction.

In the dependent claims advantageous developments are given. Thus, in an advantageous development, the ratio between maximum cross section A2 and inflow cross section A1 is as follows: $$\mathrm{1}.\mathrm{1}<\mathrm{A}\mathrm{2}/\mathrm{A}\mathrm{1}<\mathrm{1}.\mathrm{7th}$$

Through optimization experiments and flow models it could be determined that the above relationship leads to an optimal flow.

wobei A3 den Ringkanal-Querschnitt darstellt.Furthermore, the following relationships are shown in an advantageous development: $$\mathrm{0}.\mathrm{7}<\mathrm{<figure-callout\; id="3"\; label="A"\; filenames="imgf0001.png"\; state="\{\{state\}\}">A</figure-callout>}\mathrm{3}/\mathrm{A}\mathrm{1}<\mathrm{1}.\mathrm{0}.$$

where A3 represents the annular channel cross section.

Here, too, an optimal inflow with the aforementioned values was determined by means of models and calculations.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which will be described in connection with the drawings.

Embodiments of the invention will be described below with reference to the drawings. This is not intended to represent the embodiments significantly, but the drawing, probably useful for explanations, executed in a schematic and / or slightly consumed form. With regard to additions to the teachings directly recognizable in the drawing reference is made to the relevant prior art.

Figur 1

eine schematische Querschnittsansicht eines Einströmbereichs

Figur 2

einen Schnitt B-B aus Figur 1

Figur 3

einen Schnitt A-A aus Figur 1

Figur 4

einen Schnitt A-A aus Figur 1 in einer alternativen Ausführungsform

Figur 5

einen Schnitt A-A aus Figur 1 in einer alternativen Ausführungsform

Figur 6

eine schematische Darstellung der Strömungsverhältnisse gemäß dem Stand der Technik

Figur 7

eine schematische Darstellung der Strömungsverhältnisse gemäß der Erfindung.

Show it:

FIG. 1

a schematic cross-sectional view of an inflow region

FIG. 2

a cut BB off FIG. 1

FIG. 3

a section AA FIG. 1

FIG. 4

a section AA FIG. 1 in an alternative embodiment

FIG. 5

a section AA FIG. 1 in an alternative embodiment

FIG. 6

a schematic representation of the flow conditions according to the prior art

FIG. 7

a schematic representation of the flow conditions according to the invention.

FIG. 1 shows a cross-sectional view of an inflow region 1 of a turbomachine. The turbomachine may be a steam turbine. The steam turbine is in the FIG. 1 not shown in detail. In essence, the steam turbine comprises a rotatably mounted rotor, which is rotatably mounted about a rotation axis 2. A housing, for example an inner housing, is arranged around the rotor.

A further housing, for example an outer housing, can be arranged around the inner housing. Between the rotor and the housing, a flow channel (not shown) is formed. The rotor comprises several blades on its surface. The inner housing has a plurality of guide vanes on its inner surface. The flow channel is thus formed by the guide and moving blades, wherein in operation, a thermal energy of the steam is converted into a rotational energy of the rotor. The FIG. 1 now shows the inflow region of a steam turbine, wherein the flow channel is directed in the direction of rotation axis. The inflow region 1 comprises an inflow ring channel 3. This inflow is essentially rotationally symmetrical with respect to the rotation axis 2 and has an outer boundary 4. This outer boundary 4 is rotationally symmetrical, at least from the 6 o'clock position 5 to the 3 o'clock position 7. This means that a housing radius 8 is constant from the 6 o'clock position 6 to the 3 o'clock position 7.

The inflow region furthermore has an inlet connection 9. The inflow 9 is essentially a tubular connection which connects a steam line, not shown, with the inflow channel 3. The inflow 9 has an individual geometric shape. This form will now be described in more detail. The initial contour 10 forms the connection to a tubular steam line (not shown). The cross section of the initial contour 10 can thus be circular. But there are also other geometric tubular contours possible. This initial contour 10 comprises a lower nozzle limb 11, which is formed such that it adjoins the 6 o'clock position 5. This means that the lower nozzle limiter 11 is directed tangentially to the axis of rotation 2 to the outer boundary 4. In this case, the lower nozzle boundary 11 may well be arranged so that in the vicinity of the initial contour 10, this is arranged under the outer boundary 4 at the 6 o'clock position 5. The lower nozzle limiter 11 on the initial contour 10 is thus lower by a vertical distance 12 than the outer boundary 4 in the 6 o'clock position 5.

The inflow neck 9 further includes an upper neck boundary 13. The upper neck boundary 13 begins from the initial contour 10 and describes a semicircular arc up to the 3 o'clock position 7. At the 3 o'clock position 7, the upper neck boundary 13 closes tangentially outer boundary 4 on. The inflow pipe 9 thus opens into the inflow ring channel 3. The inflow ring channel 3 essentially has an annular channel cross-section A3 (not shown in detail) and is fluidically connected to the flow channel (not shown). For the sake of clarity is in the FIG. 1 the annular channel cross section A3 in the 9 o'clock position 14, in the 12 o'clock position 15 and in the 3 o'clock position 7 are drawn.

The inflow 9 has at the initial contour 10 an inflow cross section A1. The inflow section A1 can have a circular or oval shape. In operation, a flow medium, in particular steam in a steam turbine as an embodiment of the turbomachine flows in a flow direction 16 in the inflow channel 3. The flow of steam into the inflow channel is complex and will later in the FIG. 6 and FIG. 7 described in more detail. For the understanding of in FIG. 1 shown contour is shown for clarity, the flow through a flow line 17. The flow line 17 should be substantially represent the movement of the flow medium in the inflow channel. The flow thus begins at the initial contour 10 and is deflected approximately in the 5 o'clock position 18 in the initial direction. Along the flow line 17, the inflow cross section A1 has a certain value and increases to a maximum cross section A2. The maximum cross section is in the FIG. 1 drawn by a line, where the line also represents a section AA, in FIGS. 3, 4 and 5 will be described in more detail. According to the invention, the cross section in the flow direction 16 is thus reduced to an inflow cross section A1 and then to the annular channel cross section A3. This causes the flow to slow down and accelerate again, but in a different direction. In other words, the flow velocity is slowed down in the course of the cross-sectional inlet for entry into the annular channel and then accelerated again, wherein a portion of the velocity in the tangential direction is converted into a velocity component in the radial direction. This radial flow velocity component obstructs the path of the circumferential tangential flow and thus axially forces the vapor into the flow channel. This minimizes inflow losses.

Where: $$\mathrm{1}.\mathrm{1}<\mathrm{A}\mathrm{2}/\mathrm{A}\mathrm{1}<\mathrm{1}.\mathrm{7}\mathrm{and}\mathrm{0}.\mathrm{7}<\mathrm{A}\mathrm{3}/\mathrm{A}\mathrm{1}<\mathrm{1}.\mathrm{0}$$

The FIG. 2 shows a sectional view taken along the line II-II FIG. 1 , The line 19 shows the inflow section A1 and the lines 20, 21 and 22 three different embodiments, which are described as follows. The line 20 describes a contour in which the ratio A2 / A1 = 1. The line 21 describes a contour in which the ratio A2 / A1 = 1.25. The line 22 describes a contour in which the ratio A2 / A1 = 1.55.

The FIG. 3 shows a section along the line AA FIG. 1 , The FIGS. 4 and 5 show further cross sections, along the interface AA FIG. 1 for different circumstances. So shows FIG. 3 the ratio A2 / A1 = 1.55. The FIG. 4 shows the ratio A2 / A1 = 1.25 and the FIG. 5 shows the ratio A2 / A1 = 1.

The FIG. 6 shows a schematic representation of the flow conditions in the inflow region 1 in a lossy flow. The cutout 23 shows a perspective view of the inflow neck of the inflow region 1. The FIG. 6 shows an embodiment in which the cross section is not increased in the flow direction. In FIG. 6 In addition, it is shown that the flow in the inflow region has a strong peripheral component in a critical region 24. The FIG. 7 On the other hand, an embodiment according to the invention of the inflow neck 9 is shown. The further section 24 shows a perspective view of the inflow neck 9 of the inflow region 1. It can be seen that the cross-section A1 extending there is enlarged in the direction of flow to a maximum cross-section A2 on an initial contour 10 and subsequently is reduced to a constant annular channel cross-section A3. In the FIG. 1 embodiment shown shows a single valve arrangement. For reasons of clarity, the contour of a possible second valve guide 25 has been shown.

Although the invention has been further illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims (7)

Comprising turbomachine
a rotor rotatably mounted about a rotation axis (2), a housing arranged around the rotor and a flow passage formed between the rotor and the housing,
further comprising an inflow region (1) which has an inlet connection (9) and opens into an inflow channel (3),
wherein the inflow ring channel (3) essentially has an annular channel cross-section (A3) and is fluidically connected to the flow channel,
wherein the inflow ring channel (3) is formed around the rotation axis (2),
wherein the inflow pipe (9) has an inflow cross section (A1) through which a flow medium flows in a flow direction during operation,
wherein the cross section increases in the flow direction to a maximum cross section (A2) and then reduced to the annular channel cross section (A3). Turbomachine according to claim 1,
wherein the inflow ring channel (3) is formed substantially rotationally symmetrical about the axis of rotation (2). Turbomachine according to claim 1 or 2,
wherein the flow direction (16) in the region of the Einströmstutzens (9) is formed substantially tangentially to the inflow ring channel (3). Turbomachine according to claim 1, 2 or 3,
where: $$\mathrm{1}.\mathrm{1}<\mathrm{A}\mathrm{2}/\mathrm{A}\mathrm{1}<\mathrm{1}.\mathrm{7th}$$

Turbomachine according to one of the preceding claims, wherein: $$\mathrm{0}.\mathrm{7}<\mathrm{A}\mathrm{3}/\mathrm{A}\mathrm{1}>\mathrm{1}.\mathrm{0th}$$

Method for connecting an inflow nozzle (9) to an inflow channel (3),
wherein the cross section of the Einströmstutzens (A1) over the Einströmringkanal cross section (A3) is increased and then the cross section of the inflow (A1) is reduced. Method according to claim 6,
wherein a flow of a flow medium in the inflow pipe (9) is first accelerated and then slowed down and deflected in another direction.

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