EP2025945B1 - Flow working machine with ring canal wall fitting - Google Patents

Description

The aerodynamic load capacity and efficiency of fluid flow machines, such as fans, compressors, pumps and fans, is limited in particular by the growth and separation of boundary layers in the rotor and stator tip region near the housing or hub wall. This results in blade rows with running gap at higher load to Rückströmerscheinungen and the occurrence of instability of the machine. Prior art fluid power machines either have no special features to remedy this problem (see Fig.1 ) or as a countermeasure so-called "Casing Treatments" are used, which consist of various configurations of chambers and / or angular slots, mostly in the housing above the rotor.

• US 2005/0226717 A1 (Flow Control Arrangement)
• DE 101 35 003 C1 (Verdichtergehäusestruktur)
• DE 103 30 084 A1 (Rezirkulationsstruktur für Turboverdichter)

Known solutions are disclosed, for example, in the following documents:

• US 2005/0226717 A1 (Flow Control Arrangement)
• DE 101 35 003 C1 (Compressor housing structure)
• DE 103 30 084 A1 (Recirculation structure for turbocompressors)

The present invention thus relates to fluid flow machines such as fans, compressors, pumps and fans, in both axial, semi-axial and radial designs. The working medium or fluid may be gaseous or liquid.

The turbomachine according to the invention may comprise one or more stages, each with a rotor and a stator.

According to the invention, the rotor consists of a number of blades, which are connected to the rotating shaft of the fluid flow machine and energy to the Release working medium. The rotor is designed with a free blade end on the housing. The stator according to the invention consists of a number of fixed blades, which are designed on the housing side with a fixed blade end.

According to the invention, the turbomachine in front of the first rotor may have a special form of stator, a so-called leading wheel.

According to the invention, at least one stator or Vorleitrad may be rotatably mounted deviating from the immovable fixation in order to change the angle of attack. An adjustment is made for example by a spindle accessible from outside the annular channel.

In a particular embodiment, the turbomachine may have at least one row of adjustable rotors.

According to the invention, the fluid flow machine can alternatively also have a bypass configuration such that the single-flow annular channel divides behind a specific row of blades into two concentric annular channels, which in turn each comprise at least one further row of blades. Fig. 2 shows examples according to the invention relevant flow machines.

Simple existing concepts of "casing treatments" in the form of slots and / or chambers in the annular channel wall provide an increase in the stability of the fluid power machine. However, this is achieved due to the unfavorably chosen arrangement or shaping only at loss of efficiency.

In particular, the invention relates to the shape of a portion of the annular channel wall and the arrangement and shaping of recesses in said annular channel wall portion in the region of a blade row with free end and running gap of a fluid flow machine.

From the DE 103 30 084 A1 a recirculation structure for turbo compressors is previously known, which shows a circumferential annular chamber. At the rear end, seen in the flow direction, fluid enters around the entire circumference of the annular chamber, is then directed counter to the direction of flow and is conducted between vanes which are scoop-shaped and cause a swirl change of the flow. After flowing through the guide elements, the flow enters an annular region of the annular chamber and flows from there back into the flow path.

The present invention has for its object to provide a fluid flow machine of the type mentioned, which has an effective boundary layer influence in the blade tip area while avoiding the disadvantages of the prior art.

According to the invention the object is achieved by the feature combination of the main claim, the subclaims show further advantageous embodiments of the invention.

Fig.1:

eine Skizze des Standes der Technik;

Fig.2:

Beispiele erfindungsgemäß relevanter Strömungsarbeitsmaschinen;

Fig.3:

eine Skizze der erfindungsgemäßen Lösung;

Fig.4:

eine Definition erfindungsrelevanter Größen, Teil 1, Meridianschnitt;

Fig. 5a:

eine Definition erfindungsrelevanter Größen, Teil 2, Meridianschnitt;

Fig. 5b:

erfindungsgemäße Umrissformen der Ringkanalwandausnehmung;

Fig. 6:

eine Definition erfindungsrelevanter Größen, Ansicht Y-Y;

Fig. 7a:

eine Ansicht Z-Z, Teil 1;

Fig. 7b:

eine Ansicht Z-Z, Teil 2;

Fig. 7c:

eine Ansicht Z-Z, Teil 3.

In the following the invention will be described by means of embodiments in conjunction with the figures. Showing:

Fig.1:

a sketch of the prior art;

Figure 2:

Examples of relevant flow working machines according to the invention;

Figure 3:

a sketch of the solution according to the invention;

Figure 4:

a definition of variables relevant to the invention, part 1, meridian section;

Fig. 5a:

a definition of variables relevant to the invention, part 2, meridian section;

Fig. 5b:

Outline of the invention Ringkanalwandausnehmung;

Fig. 6:

a definition of invention-relevant variables, view YY;

Fig. 7a:

a view ZZ, part 1;

Fig. 7b:

a view ZZ, part 2;

Fig. 7c:

a view ZZ, Part 3.

The Fig. 1 shows, marked by dashed borders, the invention relevant zones, namely areas of the fluid flow machine with free blade ends with running gap.

The Figure 3 shows a sketch of a solution according to the invention with at least one recess which is characterized by a partial overlap with the running path of the relevant row of blades. It may also be advantageous to let the recess or the recess group also partially extend into the bladed region of a possibly upstream blade row.

The Figure 4 shows a relevant to the invention section of the flow machine, consisting of the portion of a hub or housing assembly with the annular channel wall formed thereby and the blade row located in this area. The configuration may be either a pair of rotor blade rows and a housing assembly, or a pair of stator blade rows and a hub assembly. Also shown are an optionally upstream arranged row of blades as well as the projected into the illustrated meridian plane outline of the invention Ringkanalwandausnehmung. A small arrow indicates the machine axis direction and a thick arrow indicates the main flow direction. Furthermore, there are six characteristic points of the configuration. These are first the blade tip points at the leading and trailing edges A and B. The front and rear boundaries of the annular channel wall recess on the main flow path are marked with the points E and F. In addition, two additional auxiliary points C and D are found upstream of the relevant blade row, with the help of which the course of the annular channel wall is characterized.

The 5a shows a reduced representation of the features Figure 4 , but now with more points and geometrical details. Between the blade tip points A and B, the reference chord length L is defined. All distances given are in the illustrated meridian plane (plane formed by axial direction x and radial direction r) parallel to the course of the blade tip, ie parallel to the connecting line AB measured. The auxiliary point D lies upstream of A at a distance d = 0.25 L.

The auxiliary point C lies upstream of A at a distance c = 0.75 L. A straight line through the auxiliary points C and D encloses a straight line through the blade tip points A and B the angle alpha.

According to the invention, the angle alpha in the indicated directional convention is between -15 ° and 30 °.

According to the invention, the front boundary point of the annular channel wall recess E is located at a distance e> 0 in front of the leading edge point A. In special cases, point E can also be arranged in the bladed region of another row of blades possibly located upstream of the blade row.

According to the invention, the rear boundary point of the annular channel wall recess F is at a distance f behind the leading edge point A, where 0.5 L> f> 0.

The orthogonal on the line A-B through the point A gives the point S as an intersection with the projected outline of the Ringkanalwandausnehmung.

According to the invention, the angle beta is positive in the drawn direction and is given between the straight line through the blade tip points A and B and a tangent to the contour of the annular channel wall recess, at least at one point in the outline of the recess between S and F given in the meridian section minimum 15 ° and maximum 70 °. In this way, it is ensured that the fluid which is pressed into the recess by the blade in the overlap region (region between points S and B), passes in an effective manner upstream of the blade row.

In a particularly favorable embodiment of the annular channel wall recess, the angle beta is at least at one point of the outline given in the meridian section of the recess between E and S between 15 ° and 40 °. In this way, a particularly gentle re-entry of the fluid upstream of the blade row is made possible in the main flow path.

5 b shows some possible according to the invention outline shapes of the Ringkanalwandausnehmung. In this case, the outline shape can be completely curved or straight. As production technology easily achievable formation of the recess according to the invention is particularly the bottom left and right in 5 b illustrated triangular shape.

The Figure 6 shows the view YY, as in Fig. 5a is drawn. Shown here is a pair of rotor blade row and housing, but the following statements also apply to the analogue representable pairing of stator blade row and hub.

The figure shows two blade tips in the vicinity of a portion of the housing wall. The annular channel wall (here exemplary housing) has a number of recesses which are arranged distributed in the circumferential direction. In a particularly advantageous solution according to the invention, the recesses, unlike in Figure 6 shown, arranged at different distances in the circumferential direction to each other. The recesses are shown approximately at the position of their maximum penetration depth into the channel wall. The recesses according to the invention have an angle of inclination gamma against the radial direction of the machine. The inclination of the recesses is according to the invention 25 ° <gamma <75 ° and shows accordingly in the direction of the blades moving relative to them. The size of the penetration depth and the choice of shape at the foot of the recess are of minor importance to the present invention and therefore freely selectable. The Fig.7a to 7c each show in the view ZZ a settlement of the circumference of the fluid flow machine in the region of the Ringkanalwandausnehmung. Dotted indicate two blades of the relevant row of blades, on which the recess is arranged. Shown are, in partial overlap with the blade row, the openings of an array of recesses on the annular channel wall. According to the invention, the openings in the flow direction of slender nature, ie, the extent in the circumferential direction is smaller than the extent perpendicular thereto.

The Fig. 7a shows the alignment of the recess openings in the direction of the machine axis (left half of the picture) and a further arrangement according to the invention, in which the slender openings of the recesses are inclined against the machine axis direction by the angle delta. According to the invention, the angle delta can assume values of up to 35 ° and thus guarantees an opposite staggering of the recess openings and the profiles of the relevant row of blades.

The Fig. 7b shows two arrangements according to the invention, which are used in the invention differently long and / or differently positioned recesses along the circumference.

The Fig. 7c shows two arrangements according to the invention, in which a variation of the width of the recess opening in the longitudinal direction is provided in the invention.

In the flow machine according to the invention thus a previously unattained level of space-saving Randströmungsbeeinflussung is achieved, which also allows a significant reduction in construction and cost (less variable stators and Zwischenstufenabblasung), the Prior art machines would be required to provide sufficient operating range. This is possible with different types of fluid flow machines such as fans, compressors, pumps and fans. Depending on the degree of utilization of the concept, reductions in costs and weight for the turbomachine of 10% to 20% can be achieved. In addition, there is an improvement in the efficiency, which is to be quantified with 0.2% to 0.5%.

LIST OF REFERENCE NUMBERS

1

casing

2

wave

3

rotor blade

4

stator

5

recess

6

machine axis

Claims (9)

1. Fluid-flow machine with a flow path provided by a casing (1) and a rotating shaft (2), in which path rows of rotor blades (3) and stator blades (4) are arranged, characterized in that a row of recesses (5) arranged distributed in the circumferential direction is disposed in a blade (3, 4) tip area in an annulus duct wall of the casing (1) and/ or the shaft (2), where the cross-section and the position of each recess (5) are defined as follows:

   - a limit point E of the recess (5) upstreamly arranged in the flow direction features a distance e > 0 to the forward blade tip point A,

   - a limit point F of the recess (5) downstreamly arranged in the flow direction features a distance f to the forward blade tip point A,

   - where the following applies: 0.5 L > f > 0,

   - with L being defined as the distance between the blade tip points A and B,

   - with the wall of the recess (5) including a point S, which is arranged on an orthogonal on line A-B through the point S,

   - with a straight line through the blade tip points A and B and a tangent to the wall of the recess (5) including an angle beta amounting to 15° ≤ beta ≤ 70° in at least one point of the wall of the recess (5) provided in a meridional section between the points S and F,

   - with all points lying in a meridional plane established by an axial direction x of the axis (6) of the fluid-flow machine and a radial direction r,

   - with all distances being measured parallelly to a line connecting a forward blade tip point A and a rearward blade tip point B,

   - with two further points C and D characterizing the course of the annulus duct wall upstream of the recess, C at a distance of 0.75 L to the blade tip point A and D at a distance of 0.25 L to the blade tip point A, and

   - with the connecting line A-B and the connecting line C-D including an angle -15° < alpha < 30°.
2. Fluid-flow machine in accordance with Claim 1, characterized in that the angle beta amounts to 15° ≤ beta ≤ 40°.
3. Fluid-flow machine in accordance with one of the Claims 1 or 2, characterized in that the point E is arranged in the bladed area of a further blade row disposed upstream of the blades (3, 4) under consideration.
4. Fluid-flow machine in accordance with one of the Claims 1 to 3, characterized in that the wall of the recess (5) is given a completely curved shape.
5. Fluid-flow machine in accordance with one of the Claims 1 to 3, characterized in that the wall of the recess (5) extends rectilinearly, at least in a partial area.
6. Fluid-flow machine in accordance with one of the Claims 1 to 5, characterized in that the recess (5) features an inclination angle gamma amounting to 25° ≤ gamma ≤ 75° towards the radial direction r of the fluid-flow machine.
7. Fluid-flow machine in accordance with one of the Claims 1 to 6, characterized in that one longitudinal edge of the recess (5) is inclined against the direction of the machine axis (6) by an angle delta amounting to delta ≤ 35°.
8. Fluid-flow machine in accordance with one of the Claims 1 to 7, characterized in that at least one recess (5) in its opening section on the annulus duct wall features a varying width or extension in the circumferential direction.
9. Fluid-flow machine in accordance with one of the Claims 1 to 8, characterized in that, in the case of several recesses (5), two circumferentially adjacent recesses feature different positions or extensions (both in the axial and in the circumferential direction).

Images