CN108223023A - Flow control method and device based on groove jet stream - Google Patents

Abstract

The invention discloses a flow control method and device based on a grooved jet, in which a groove is opened at the blade chord position at the top of the blade and at a preset distance from the edge of the blade to form a grooved jet, wherein the method includes the following steps: according to The first control equation curve based on the quadratic function is obtained for the blade thickness; the second control equation curve based on the quadratic function is obtained according to the width of the groove and the blade thickness; the groove is controlled respectively according to the first control equation curve and the second control equation curve The molded lines on both sides of the blade control the width of the groove to gradually decrease from the front of the blade to the back of the blade, so that the slotted jet and the main leakage vortex form a nearly right-angle impact and weaken the leakage vortex. This method can significantly weaken the leakage vortex of the blade tip clearance while ensuring the energy characteristics of the blade, thereby optimizing the flow form in the flow channel, and the slotting structure is simple and easy to implement, which can better ensure the high efficiency and stability of various impellers using blades run.

Description

Flow control method and device based on groove jet

technical field

The invention relates to the technical field of impeller blades, in particular to a flow control method and device based on groove jet flow.

Background technique

Energy is the foundation of human survival and development, how to utilize and convert energy has become one of the hot issues that human beings pay attention to. As the core conversion equipment of energy, the performance of the impeller blade has a key impact on the energy conversion efficiency. Among them, the blade tip clearance is the gap between the top of the blade and the inner wall of the casing, and its size is usually small, but the phenomena such as leakage flow and vortex motion caused by it have an important impact on the internal flow shape of the impeller, and then affect the operating efficiency of the impeller and stability.

At present, the mechanism of the tip clearance flow has been studied in depth, but the method of controlling the tip clearance flow in the impeller is still rare. In order to optimize the flow shape in the impeller and reduce the influence of the gap leakage vortex on its performance, a new method of flow control is urgently needed.

Contents of the invention

The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

Therefore, an object of the present invention is to propose a flow control method based on grooved jets, which can better ensure the efficient and stable operation of various types of impellers using blades.

Another object of the present invention is to propose a groove jet based flow control device.

In order to achieve the above-mentioned purpose, an embodiment of the present invention proposes a flow control method based on grooved jets, in which grooves are opened at the blade chord position at the top of the blade and at a predetermined distance from the edge of the blade to form a grooved jet, wherein , the method includes the steps of: obtaining a first control equation curve based on a quadratic function according to the blade thickness; obtaining a second control equation curve based on a quadratic function according to the width of the groove and the blade thickness; according to the The first control equation curve and the second control equation curve respectively control the profile lines on both sides of the groove, so as to control the width of the groove to gradually decrease from the front of the blade to the back of the blade, so that the slotted jet and the main The leakage vortex forms a nearly right-angle impact and weakens the leakage vortex.

In the flow control method based on grooved jets in the embodiment of the present invention, the profile lines on both sides of the groove can be controlled respectively according to the first control equation curve and the second control equation curve, so as to control the width of the groove to gradually decrease from the front of the blade to the back of the blade. Small, so that the slotted jet and the main leakage vortex form a nearly right-angle impact, while ensuring the energy characteristics of the blade, it significantly weakens the leakage vortex in the blade tip clearance, thereby optimizing the flow form in the flow channel, and better ensuring various types of impellers using blades efficient and stable operation.

In addition, the groove jet-based flow control method according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

Further, in one embodiment of the present invention, the first control equation curve is

Wherein, _t3 is the thickness of the blade corresponding to the first curve, b is the coefficient of the quadratic function, and z is the z-axis coordinate in the Cartesian coordinate system.

Further, in one embodiment of the present invention, the second control equation curve is:

Wherein, _t4 is the thickness of the blade corresponding to the second curve, and w is the groove width.

Further, in one embodiment of the present invention, it also includes: adjusting the depth of the groove, so as to adjust the depth according to the quadratic function coefficient, the width of the groove, the depth of the groove, and the rotation angle The interaction effect between the slotted jet and the main leakage vortex is ensured.

Further, in one embodiment of the present invention, the depth of the groove is 20%-50% of the value of the blade tip clearance, and the chord position of the preset distance is 10%-50% from the leading edge of the blade. 30% leaf chord position.

In order to achieve the above-mentioned purpose, another embodiment of the present invention proposes a flow control device based on grooved jets, in which grooves are opened at the blade chord position at the top of the blade and at a predetermined distance from the edge of the blade to form a grooved jet, Wherein, the device includes: a first acquisition module, used to obtain the first control equation curve based on the quadratic function according to the thickness of the blade; a second acquisition module, used to obtain the curve based on the quadratic function according to the width of the groove and the thickness of the blade The second control equation curve of the quadratic function; the control module is used to control the two sides of the groove respectively according to the first control equation curve and the second control equation curve, so as to control the width of the groove It gradually decreases from the front of the blade to the back of the blade, so that the slotted jet forms a nearly right-angle impact with the main leakage vortex, weakening the leakage vortex.

The flow control device based on the grooved jet in the embodiment of the present invention can control the profile lines on both sides of the groove respectively according to the first control equation curve and the second control equation curve, so as to control the width of the groove to gradually decrease from the front of the blade to the back of the blade. Small, so that the slotted jet and the main leakage vortex form a nearly right-angle impact, while ensuring the energy characteristics of the blade, it significantly weakens the leakage vortex in the blade tip clearance, thereby optimizing the flow form in the flow channel, and better ensuring various types of impellers using blades efficient and stable operation.

In addition, the groove jet-based flow control device according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

Further, in one embodiment of the present invention, the first control equation curve is

Wherein, _t3 is the thickness of the blade corresponding to the first curve, b is the coefficient of the quadratic function, and z is the z-axis coordinate in the Cartesian coordinate system.

Further, in one embodiment of the present invention, the second control equation curve is:

Wherein, _t4 is the thickness of the blade corresponding to the second curve, and w is the groove width.

Further, in one embodiment of the present invention, it also includes: an adjustment module, configured to adjust the depth of the groove, so as to , the rotation angle guarantees the interaction effect between the slotted jet and the main leakage vortex.

Further, in one embodiment of the present invention, the depth of the groove is 20%-50% of the value of the blade tip clearance, and the chord position of the preset distance is 10%-50% from the leading edge of the blade. 30% leaf chord position.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

1 is a flowchart of a flow control method based on grooved jets according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of the mold lines on both sides of the groove according to an embodiment of the present invention;

3 is a schematic diagram of a three-dimensional shape of a blade and a groove structure according to an embodiment of the present invention;

Fig. 4 is a schematic diagram of the simulation calculation results of the flow control method based on the groove jet according to an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a groove jet-based flow control device according to an embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

The flow control method and device based on the groove jet according to the embodiment of the present invention will be described below with reference to the accompanying drawings. First, the flow control method based on the groove jet according to the embodiment of the present invention will be described with reference to the accompanying drawings.

Fig. 1 is a flow chart of a groove jet-based flow control method according to an embodiment of the present invention.

As shown in Figure 1, the groove jet-based flow control includes the following steps:

In step S101, a first control equation curve based on a quadratic function is obtained according to the thickness of the blade.

Wherein, in one embodiment of the present invention, the first governing equation curve is

Wherein, t ₃ is the thickness of the blade corresponding to the first curve, b is the quadratic function coefficient, and z is the z-axis coordinate in the Cartesian coordinate system, that is, the coordinate along the blade thickness direction.

It can be understood that, as shown in Figure 2, in order to control the jet velocity and jet direction in the embodiment of the present invention, the profile lines on both sides of the groove can be controlled by two curves based on quadratic functions, so that the width w of the groove is from the front of the blade to the The back gradually decreases.

Among them, the governing equation of edge 3, that is, the first governing equation curve is t ₃ is the thickness of the blade corresponding to the edge 3, and in the embodiment of the present invention, different edge forms can be realized by changing the value of b, wherein

In step S102, a second control equation curve based on a quadratic function is obtained according to the width of the groove and the thickness of the blade.

Wherein, in one embodiment of the present invention, the second control equation curve is:

Wherein, _t4 is the thickness of the blade corresponding to the second curve, and w is the width of the groove.

It can be understood that, as shown in Figure 2, in the groove structure, the governing equation of edge 4, that is, the second governing equation curve is defined by the curve Obtained by rotating angle α around point A, _t4 is the blade thickness corresponding to sideline 4, and the value of b is consistent with the curve of the first control equation,

In step S103, according to the first control equation curve and the second control equation curve, the two sides of the groove are respectively controlled to control the width of the groove to gradually decrease from the front of the blade to the back of the blade, so that the slotted jet and the main leakage vortex A nearly right-angle impact is formed to weaken the leakage vortex.

Further, in one embodiment of the present invention, the method of the embodiment of the present invention also includes: adjusting the depth of the groove, so as to ensure that the grooved jet flow Effect with the main leakage vortex.

It can be understood that, as shown in Figure 2, as the working conditions change, the embodiment of the present invention can change the quadratic function coefficient b, groove width w, rotation angle α, and groove depth of the two sides of the groove. h to change the effect of the slotted jet and the main leakage vortex.

Further, in one embodiment of the present invention, the depth of the groove is 20%-50% of the value of the blade tip clearance, and the preset distance of the blade chord is 10%-30% of the blade chord from the leading edge of the blade. s position.

It can be understood that, in the embodiment of the present invention, grooves can be opened at the top of the blade, 10%-30% of the chord from the leading edge of the blade, to form slotted jets, and the jets can form a nearly right-angle impact with the main leakage vortex, so that the leakage The vortex is significantly weakened, the groove depth h can be adjusted, and the groove depth h is 20%-50% of the blade tip clearance value δ.

In addition, as shown in Figure 3, x is the span direction of the blade, y is the direction of the chord length of the blade, and z is the direction of the thickness of the blade. The embodiment of the present invention can be at the top of the blade 1, 10%-30% of the chord position from the leading edge of the blade. Open through the groove 2 to form a slotted jet, which forms a nearly right-angle impact with the main leakage vortex, so that the leakage vortex is significantly weakened. In a specific embodiment of the present invention, the flow control based on the grooved jet of the embodiment of the present invention The steps of the method are as follows:

As shown in Fig. 2 and Fig. 3, the embodiment of the present invention is to control the jet velocity and jet direction, and the profile lines on both sides of the groove are controlled by two curves based on quadratic functions, so that the groove width w gradually decreases from the front to the back of the blade. Small. where the first governing equation is t ₃ is the blade thickness corresponding to the first control equation; different edge forms can be realized by changing the value of b, where The second governing equation can be given by the curve Obtained by rotating the angle α around point A, _t4 is the blade thickness corresponding to the second control equation, where the value of b is consistent with the first control equation,

As shown in Fig. 4, Fig. 4 shows the three-dimensional structure of the leakage vortex in the flow channel of the embodiment of the present invention (defined by the Q criterion, with a value of 3×10 ⁷ s ^-2 ). Wherein, Fig. 4 (a) is a schematic diagram of not slotting, and Fig. 4 (b) is a schematic diagram of slotting according to an embodiment of the present invention. As can be seen from Fig. 4, the slotting jet caused by the groove 2 and the main leakage vortex form nearly Right-angle impact (shown in the dotted box in Figure 4(b)), through calculation, it is found that the amount of vortex in the flow channel is reduced by nearly 20% after the groove 2 is added, so that the main leakage vortex is significantly attenuated.

In addition, the depth h of the groove 2 can be adjusted, and the depth h of the groove 2 is 20%-50% of the blade tip clearance value δ; as the working conditions change, the quadratic function of the profile line on both sides of the groove can be changed Coefficient b, groove width w, rotation angle α, and groove depth h are used to change the effect of the slotted jet and the main leakage vortex.

According to the flow control method based on the groove jet proposed in the embodiment of the present invention, the profile lines on both sides of the groove can be controlled respectively according to the first control equation curve and the second control equation curve, so as to control the width of the groove from the front of the blade to the back of the blade Gradually decreases, so that the slotted jet and the main leakage vortex form a nearly right-angle impact, while ensuring the energy characteristics of the blade, it significantly weakens the leakage vortex in the tip clearance, thereby optimizing the flow form in the flow channel, and better ensuring the use of various types of blades. The efficient and stable operation of the impeller-like impeller has a simple groove structure, which has little influence on the blade structure, is easy to process and manufacture, and has a wide range of applications, and can be used for blades in various impellers.

Next, the groove jet-based flow control device proposed according to the embodiments of the present invention will be described with reference to the accompanying drawings.

Fig. 5 is a schematic structural diagram of a groove jet-based flow control device according to an embodiment of the present invention.

As shown in FIG. 5 , the groove jet-based flow control device 10 includes: a first acquisition module 100 , a second acquisition module 200 and a control module 300 .

Wherein, the first obtaining module 100 is used to obtain the first control equation curve based on the quadratic function according to the thickness of the blade. The second acquisition module 200 is used to obtain a second control equation curve based on a quadratic function according to the width of the groove and the thickness of the blade. The control module 300 is used to control the profile lines of both sides of the groove respectively according to the first control equation curve and the second control equation curve, so as to control the width of the groove to gradually decrease from the front of the blade to the back of the blade, so that the slotted jet flow and the main leakage vortex A nearly right-angle impact is formed to weaken the leakage vortex. The device 10 of the embodiment of the present invention can significantly weaken the leakage vortex of the blade tip clearance while ensuring the energy characteristics of the blade, thereby optimizing the flow form in the flow channel, and the slotting structure is simple and easy to implement, which can better ensure that the blades are used. Efficient and stable operation of similar impellers.

Further, in one embodiment of the present invention, the first control equation curve is

Wherein, t ₃ is the thickness of the blade corresponding to the first curve, b is the quadratic function coefficient, and z is the z-axis coordinate in the Cartesian coordinate system, that is, the coordinate along the blade thickness direction.

Further, in one embodiment of the present invention, the second control equation curve is:

Wherein, _t4 is the thickness of the blade corresponding to the second curve, and w is the groove width.

Further, in an embodiment of the present invention, the device 10 of the embodiment of the present invention further includes: an adjustment module. Wherein, the adjustment module is used to adjust the depth of the groove, so as to ensure the effect of the slotted jet and the main leakage vortex according to the quadratic function coefficient, the width of the groove, the depth of the groove, and the rotation angle.

Further, in one embodiment of the present invention, the depth of the groove is 20%-50% of the value of the blade tip clearance, and the preset distance of the blade chord is 10%-30% of the blade chord from the leading edge of the blade. s position.

It should be noted that the foregoing explanations on the embodiment of the groove jet-based flow control method are also applicable to the groove jet-based flow control device of this embodiment, which will not be repeated here.

According to the flow control device based on the groove jet proposed in the embodiment of the present invention, the profile lines on both sides of the groove can be controlled respectively according to the first control equation curve and the second control equation curve, so as to control the width of the groove from the front of the blade to the back of the blade Gradually decreases, so that the slotted jet and the main leakage vortex form a nearly right-angle impact, while ensuring the energy characteristics of the blade, it significantly weakens the leakage vortex in the tip clearance, thereby optimizing the flow form in the flow channel, and better ensuring the use of various types of blades. The efficient and stable operation of the impeller-like impeller has a simple groove structure, which has little influence on the blade structure, is easy to process and manufacture, and has a wide range of applications, and can be used for blades in various impellers.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship indicated by "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device or element Must be in a particular orientation, be constructed in a particular orientation, and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection , or integrated; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise specified limit. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In the present invention, unless otherwise clearly specified and limited, the first feature may be in direct contact with the first feature or the first and second feature may be in direct contact with the second feature through an intermediary. touch. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (10)

1. a kind of flow control method based on groove jet stream, which is characterized in that vane tip and away from blade edge preset away from From chord of foil position open perforation groove, to form fluting jet stream, wherein, the described method comprises the following steps：

The first governing equation curve based on quadratic function is obtained according to vane thickness；

The second governing equation curve based on quadratic function is obtained according to the width of the groove and the vane thickness；And

Control the both sides molded line of the groove respectively according to the first governing equation curve and the second governing equation curve, It is gradually reduced from face of blade to vacuum side of blade with the width for controlling the groove so that the fluting jet stream and major leak volute It is impacted into nearly right angle, weakens leakage vortex.

2. the flow control method according to claim 1 based on groove jet stream, which is characterized in that first controlling party Journey curve is

Wherein, t₃For the thickness of the corresponding blade of first curve, b is quadratic function coefficient, and z is cartesian coordinate system Middle z-axis direction coordinate.

3. the flow control method according to claim 2 based on groove jet stream, which is characterized in that second controlling party Journey curve is：

Wherein, t₄For the thickness of the blade corresponding to second curve, w is recess width.

4. the flow control method according to claim 3 based on groove jet stream, which is characterized in that further include：

Adjust the depth of the groove, with according to the quadratic function coefficient, the groove width, the depth of the groove, The rotation angle ensures the fluting jet stream and the function and effect in the major leak whirlpool.

5. the flow control method according to claim 4 based on groove jet stream, which is characterized in that the depth of the groove For the 20%-50% of taken blade tip clearance value, and the chord of foil position of the pre-determined distance is away from blade inlet edge 10%-30% chord of foils Position.

6. a kind of flow control apparatus based on groove jet stream, which is characterized in that vane tip and away from blade edge preset away from From chord of foil position open perforation groove, to form fluting jet stream, wherein, described device includes：

First acquisition module, for obtaining the first governing equation curve based on quadratic function according to vane thickness；

Second acquisition module obtains the second control based on quadratic function for the width according to the groove and the vane thickness Equation curve processed；And

Control module is described recessed for being controlled respectively according to the first governing equation curve and the second governing equation curve The both sides molded line of slot, is gradually reduced with the width for controlling the groove from face of blade to vacuum side of blade so that the fluting is penetrated Stream is impacted with major leak volute into nearly right angle, weakens leakage vortex.

7. the flow control apparatus according to claim 6 based on groove jet stream, which is characterized in that first controlling party Journey curve is

Wherein, t₃For the thickness of the corresponding blade of first curve, b is quadratic function coefficient, and z is cartesian coordinate system Middle z-axis direction coordinate.

8. the flow control apparatus according to claim 7 based on groove jet stream, which is characterized in that second controlling party Journey curve is：

Wherein, t₄For the thickness of the blade corresponding to second curve, w is recess width.

9. the flow control apparatus according to claim 8 based on groove jet stream, which is characterized in that further include：

Adjust module, for adjusting the depth of the groove, with according to the quadratic function coefficient, the groove width, institute State the depth of groove, the rotation angle ensures the fluting jet stream and the function and effect in the major leak whirlpool.

10. the flow control apparatus according to claim 9 based on groove jet stream, which is characterized in that the depth of the groove The 20%-50% for taken blade tip clearance value is spent, and the chord of foil position of the pre-determined distance is away from blade inlet edge 10%-30% leaves The position of string.