CN117588444A - Flow control method and structure for coupling blade slotting and self-circulation processing casing - Google Patents
Flow control method and structure for coupling blade slotting and self-circulation processing casing Download PDFInfo
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/52—Casings; Connections of working fluid for axial pumps
- F04D29/54—Fluid-guiding means, e.g. diffusers
- F04D29/541—Specially adapted for elastic fluid pumps
- F04D29/542—Bladed diffusers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/52—Casings; Connections of working fluid for axial pumps
- F04D29/54—Fluid-guiding means, e.g. diffusers
- F04D29/541—Specially adapted for elastic fluid pumps
- F04D29/542—Bladed diffusers
- F04D29/544—Blade shapes
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Abstract
The invention relates to a flow control method and a flow control structure for coupling a blade slotting and a self-circulation processing casing, belonging to the technical field of flow control in impeller machinery; jet grooves are formed in the stator blades; a deflector is arranged in the jet flow groove to split jet flow entering from the inlet of the jet flow groove; a self-circulation structure is arranged between the jet flow groove and the rotor blade top; under the action of the pressure difference of the suction surface and the pressure surface of the static blade, the self-adaptive jet flows in from an inlet on the pressure surface side of the jet flow groove, flows through the guide plate, and a part of the self-adaptive jet flows to the top of the jet flow groove under the action of the guide plate, enters a self-circulation structure and finally flows into a main flow channel at the top of the rotor blade; the other part of the self-adaptive jet flows out from an outlet on the suction surface side under the action of a guide plate. The invention solves the technical problems that the stable working range of the compressor is enlarged by the traditional self-circulation casing, but the efficiency of a design point is lost.
Description
Technical Field
The invention belongs to the technical field of internal flow control of impeller machines, and particularly relates to a flow control method and structure for coupling a blade slot and a self-circulation processing casing.
Background
Modern high performance aeroengines are moving towards high thrust-weight ratios, low fuel consumption and high reliability, and researchers desire to trade fewer compressor stages for higher total compressor pressure ratios by technological means, which places higher demands on the overall performance and stability of single stage compressors. The self-circulation processing casing is used as an effective stability expanding measure, so that the stability of the air compressor can be improved, and meanwhile, the efficiency of the design working condition of the air compressor is considered, and the self-circulation processing casing is widely applied to engineering. On the other hand, as the single-stage load of the compressor is increased, a strong reverse pressure gradient exists in the blade channel of the compressor, and the airflow is easy to separate from the surface layer at the suction surface of the blade, so that the flow loss is increased. The blade slotting is used as a passive control measure, and can form self-adaptive jet flow by utilizing the pressure difference between the pressure surface and the suction surface of the blade, and the effective flow area in the blade channel is enlarged and the flow loss is reduced by improving the fluid kinetic energy in a low-speed area. However, the axial flow compressor has a reverse pressure gradient in the axial direction, and the purpose of expanding the stability of the compressor can not be achieved only by slotting the blades.
Therefore, based on the technical problems, the blade slotting and the self-circulation processing casing are coupled, and the novel flow control method for coupling the blade slotting and the self-circulation processing casing is designed, so that the design targets of reducing the flow loss in the blade channel and improving the stability of the air compressor can be realized.
Disclosure of Invention
The technical problems to be solved are as follows:
in order to avoid the defects of the prior art, reduce the flow loss in the stator blade channel and enlarge the stable working range of the compressor, the invention provides a flow control method and a flow control structure for coupling a blade slotting and a self-circulation processing casing. Three jet flow grooves are formed in the stationary blade, an airflow baffle plate capable of adjusting radial positions is arranged in each jet flow groove, and an air guiding port of the self-circulation structure is connected with the top of each jet flow groove (at the position of the casing). Compared with the traditional self-circulation casing, the novel flow control method of blade slotting and self-circulation processing casing coupling not only enlarges the stable working range of the compressor, but also can reduce the flow loss generated by boundary layer separation in the stator blade channel. The technical problem that the stable working range of the compressor is enlarged by the traditional self-circulation casing, but the efficiency of a design point is lost is solved.
The technical scheme of the invention is as follows: a flow control method for coupling blade slotting and self-circulation processing casing comprises the following specific steps:
jet grooves are formed in the stator blades;
a deflector is arranged in the jet flow groove to split jet flow entering from the inlet of the jet flow groove;
a self-circulation structure is arranged between the jet flow groove and the rotor blade top;
under the action of the pressure difference of the suction surface and the pressure surface of the static blade, the self-adaptive jet flows in from an inlet on the pressure surface side of the jet flow groove, flows through the guide plate, and a part of the self-adaptive jet flows to the top of the jet flow groove under the action of the guide plate, enters a self-circulation structure and finally flows into a main flow channel at the top of the rotor blade; the other part of the self-adaptive jet flows out from an outlet on the suction surface side under the action of a guide plate.
The invention further adopts the technical scheme that: the method for splitting the jet flow by the guide plate is that the guide plate is obliquely arranged in the jet flow groove, the position height of one end of the guide plate near the suction surface is set to be larger than the position height of one end of the pressure inlet surface, and the split flow of the two parts is controlled by adjusting the inclination; when the inclined direction of the guide plate is closer to the radial direction, the airflow flowing into the self-circulation structure is increased, and the airflow flowing out of the suction surface is reduced; when the inclined direction of the deflector is closer to the axial direction, the airflow flowing into the self-circulation structure is reduced, and the airflow flowing out of the suction surface is increased.
The flow control structure comprises jet grooves which are arranged on stationary blades and used for communicating a pressure surface and a suction surface, guide plates which are arranged in the jet grooves and used for controlling flow, and a self-circulation structure which is used for communicating the jet grooves and the tops of rotor blades;
the jet flow is introduced into the inlet at the pressure surface side of the jet flow groove, flows through the guide plate, and a part of jet flow flows to the top of the jet flow groove under the action of the guide plate, enters a self-circulation structure and finally flows into the main flow channel at the top of the rotor blade; the other part of jet flows out from the outlet on the suction surface side under the action of the guide plate.
The invention further adopts the technical scheme that: three jet grooves are arranged on the static blade, and the radial positions of the three jet grooves are in a 25% -100% blade height range; the entrance of the jet slot is positioned at the pressure surface side, and the width is 8 percent Ca; the jet flow groove outlet is positioned on the suction surface side, and the width is 5% Ca.
The invention further adopts the technical scheme that: the near suction face one end of guide plate is installed in leaf top department, and the radial height of near pressure face one end can be adjusted according to the flow demand.
The invention further adopts the technical scheme that: the height of the guide plate is adjustable, and the lower the radial height of the guide plate is, the more air flows into the self-circulation structure, the less air flows out of the suction surface; the higher its radial position, the less airflow flows into the self-circulating structure and the more airflow flows out of the suction side.
The invention further adopts the technical scheme that: the self-circulation structure comprises an air-entraining section, a bridge circuit and an air-jetting section which are sequentially arranged, wherein an air-entraining port of the air-entraining section is positioned in the radial extending direction of the jet flow groove and is communicated with an opening at the top of the jet flow groove, and jet flow in the jet flow groove, which is split by a guide plate, is led into the self-circulation structure; the bridge extends along the direction of the rotor facing the casing wall, the air-entraining end introduces jet flow into the bridge through the transition section, and the inlet section of the transition section rotates 60 degrees towards the main flow incoming direction to obtain the outlet section connected with the bridge; the inlet of the air injection section is connected with the outlet of the bridge, and the nozzle faces the front edge of the blade top of the rotor.
The invention further adopts the technical scheme that: the bridge channels are separated by built-in baffles and are divided into bridge channels which are in one-to-one correspondence with the number of jet flow grooves and air entraining sections;
or the channels in the bridge are integral channels, and jet flows of a plurality of air entraining sections are converged; by adopting the integral channel, the air flow static pressure at the outlets of the three air entraining sections is required to be ensured to be approximately equal, otherwise, due to the difference between the static pressure values of the three independent air entraining sources, the air entraining sources with lower static pressure can have the phenomenon of countercurrent or non-circulation.
The invention further adopts the technical scheme that: the jet section is designed by adopting a Coanda curve, the throat height is 0.16mm, the included angle between the jet direction of the circulating airflow and the main flow is 10 degrees, the axial distance of the jet port is 3mm, the circumferential coverage rate is 12.5%, and the axial position of the tail edge of the jet port is the same as the axial position of the front edge of the rotor blade top.
A compressor comprises a flow control structure which is coupled with novel blade slotting and self-circulation processing casings, wherein the number of the novel blade slotting and the self-circulation processing casings are consistent with that of static blades, and the novel blade slotting and the self-circulation processing casings are arranged in a one-to-one correspondence mode.
Advantageous effects
The invention has the beneficial effects that: by applying the novel flow control method of blade slotting and self-circulation processing casing coupling on the single-stage subsonic axial flow compressor, the comprehensive stall margin of the compressor is improved by 3.7%, and the isentropic efficiency absolute quantity of the compressor under the condition that the solid wall casing is close to stall is improved by 1.1%. Compared with the traditional self-circulation casing, the novel flow control method of blade slotting and self-circulation processing casing coupling not only improves the comprehensive stall margin of the compressor, but also obtains considerable efficiency increment under stall working conditions. The novel flow control method for coupling the blade slotting and the self-circulation processing casing solves the problem that isentropic efficiency of a compressor is lost to a certain extent when the traditional self-circulation processing casing expands and stabilizes.
When the single-stage subsonic axial flow compressor is under the working condition of small flow, the boundary layer of the suction surface of the static blade of the compressor can be separated due to the overlarge attack angle of the airflow, so that a large amount of low-speed fluid is generated and loss is caused. Moreover, due to expansion and disruption of the rotor tip leakage flow, a large area of low velocity region is also created within the rotor tip channel, inducing compressor instability as the compressor flow is further reduced. The air guiding port of the self-circulation structure guides the air flow of the static blade pressure surface into the self-circulation casing under the action of the air flow baffle in the jet flow groove, and the circulating air flow with higher jet speed effectively blows off low-speed fluid in the rotor blade top channel, so that the effect of improving the stability of the compressor is finally achieved. The other part of jet flow is directly sprayed out of the suction surface of the blade, so that the kinetic energy of the gas which is removed from the surface of the suction surface at a low speed is increased, the flow loss in the blade channel is reduced, and the efficiency of the gas compressor is improved.
Drawings
FIG. 1 is an overall three-dimensional view of a novel vane slot and self-circulating process cartridge coupled flow control method.
FIG. 2 is a schematic diagram of a three-dimensional geometry of a self-circulating processing casing in a novel flow control method of blade slotting and self-circulating processing casing coupling.
FIG. 3 is a partial enlarged view of a turning portion of a flow direction of a segment caused by a self-circulating processing casing in a novel flow control method in which blade slotting is coupled with the self-circulating processing casing.
FIG. 4 is a schematic diagram of the relative axial positions of the jet ports of the self-circulating processing casing and the leading edge of the tip of the rotor blade in the novel flow control method of blade slotting and self-circulating processing casing coupling.
FIG. 5 is a schematic diagram of a three-stage design of vane jet slots in a novel flow control method of vane slotting and self-circulating processing casing coupling.
Fig. 6 is a schematic view of vane jet slots and baffle structures in the jet slots in the novel flow control method of vane slotting and self-circulation processing casing coupling (only one vane suction slot and baffle structure is shown for clear and tidy pictures).
FIG. 7 is a schematic diagram of the airflow direction of the novel vane slot and self-circulation processing casing coupled flow control method, wherein solid arrows represent main flow direction, dashed arrows represent jet flow direction, and dashed arrows represent circulating airflow direction.
Reference numerals illustrate: 1. a rotor; 2. a stationary blade; 3. stationary blade jet grooves; 4. a bleed section (bleed port) of the self-circulating structure; 5. a bridge of self-circulating construction; 6. jet section (jet port) of self-circulation structure; 7. the flow guiding plate can be adjusted in the flow guiding groove.
Detailed Description
The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.
The designations defining the directions are: axial-along the direction of the cylinder axis; radial-along the radial direction of the section (perpendicular to the axis); the circumferential direction (the axial direction is perpendicular to the axis and the radius of the section) around the cylinder, the blade top, the side of the blade close to the casing is the blade top, and the blade root, the side of the blade close to the hub is the blade root.
Because the single-stage subsonic axial flow compressor is under the working condition of small flow, the boundary layer of the suction surface of the static blade of the compressor can be separated due to the overlarge attack angle of the airflow, a large amount of low-speed fluid is generated, and loss is caused. Moreover, due to expansion and disruption of the rotor tip leakage flow, a large area of low velocity region is also created within the rotor tip channel, inducing compressor instability as the compressor flow is further reduced. The invention provides a novel flow control method and a system for coupling blade slotting and a self-circulation processing casing, wherein the method comprises the following steps:
jet grooves are formed in the stator blades;
a deflector is arranged in the jet flow groove to split jet flow entering from the inlet of the jet flow groove;
a self-circulation structure is arranged between the jet flow groove and the rotor blade top;
under the action of the pressure difference of the suction surface and the pressure surface of the static blade, the self-adaptive jet flows in from an inlet on the pressure surface side of the jet flow groove, flows through the guide plate, and a part of the self-adaptive jet flows to the top of the jet flow groove under the action of the guide plate, enters a self-circulation structure and finally flows into a main flow channel at the top of the rotor blade; the other part of the self-adaptive jet flows out from an outlet on the suction surface side under the action of a guide plate.
Specifically, the method for splitting the jet flow by the guide plate is that the guide plate is obliquely arranged in the jet flow groove, the position height of one end of the guide plate near the suction surface is set to be larger than the position height of one end of the pressure inlet surface, and the split flow of the two parts is controlled by adjusting the inclination; when the inclined direction of the guide plate is closer to the radial direction, the airflow flowing into the self-circulation structure is increased, and the airflow flowing out of the suction surface is reduced; when the inclined direction of the deflector is closer to the axial direction, the airflow flowing into the self-circulation structure is reduced, and the airflow flowing out of the suction surface is increased.
Compared with a single self-circulation processing casing and a single blade slotting flow control strategy, the novel blade slotting and self-circulation processing casing coupling flow control method can utilize circulating air flow to improve the stability of the compressor; secondly, the self-adaptive jet flow can be utilized to blow off low-speed fluid generated by separation of the auxiliary surface layers, so that the flow loss in the stator blade channel is reduced; in addition, the self-circulation airflow flow and the self-adaptive jet flow can be adjusted by adjusting the radial height of the near-pressure surface end of the baffle.
Referring to fig. 1, the flow control structure of the novel blade slotting and self-circulation processing casing coupling comprises a jet slot arranged on a stator blade and used for communicating a pressure surface and a suction surface, a guide plate arranged in the jet slot and used for controlling flow, and a self-circulation structure used for communicating the jet slot and a rotor blade top; the jet flow is introduced into the inlet at the pressure surface side of the jet flow groove, flows through the guide plate, and a part of jet flow flows to the top of the jet flow groove under the action of the guide plate, enters a self-circulation structure and finally flows into the main flow channel at the top of the rotor blade; the other part of jet flows out from the outlet on the suction surface side under the action of the guide plate.
Specifically, referring to fig. 5, three jet grooves are arranged on the stator blade, the radial range of the three jet grooves is 25% -100% of the blade height, and the widths of the inlet and outlet of the jet grooves are 8% Ca and 5% Ca respectively. The jet flow groove adopts a three-section design of an inlet section, a transition section and an outlet section. For blades of smaller thickness, a two-stage design of the inlet and outlet sections may be employed.
Specifically, referring to fig. 6, a baffle is disposed in the jet slot, and the radial height of one end of the baffle near the suction surface is fixed at the top of the blade, and the radial height of one end near the pressure surface is adjustable. Referring to fig. 7, the pressure surface of the blade absorbs and the pressure surface is differential, so that the adaptive jet flow flowing in from the pressure surface to the suction surface and flowing out from the suction surface is generated in the jet groove. Under the action of the baffle plate, a part of the self-adaptive jet flows towards the top of the jet flow groove (the case) along the baffle plate, and is finally sucked into the self-circulation structure by the self-circulation air-entraining port; the other part of the adaptive jet flows out of the suction surface of the blade.
Specifically, for the baffle near pressure surface end with adjustable radial height, the lower the radial height is, the more airflow flows into the self-circulation structure, and the less airflow flows out of the suction surface; the higher its radial position, the less airflow flows into the self-circulating structure and the more airflow flows out of the suction side.
Specifically, referring to fig. 2, the self-circulation processing casing part is composed of a bleed air section, a bridge circuit and an air injection section by adopting a traditional self-circulation casing design method, but the bleed air section is provided with three bleed air ports corresponding to three independent bleed air sources respectively, and the bleed air section inlet is connected with the top of the jet slot (near the casing).
Specifically, referring to fig. 7, the flow direction of the air flow in the compressor can be summarized as: because the differential pressure effect of the static blade suction pressure surface forms self-adaptive jet flow, one part of self-adaptive jet flow flows out from the suction surface, and the other part of air flow flows upwards into the self-circulation structure under the effect of the baffle plate, and finally flows into the main flow channel at the top of the rotor blade after passing through the air entraining section, the bridge circuit and the air injection section of the self-circulation structure.
Specifically, referring to fig. 3, for the design of the transition portion of the bleed air section of the self-circulation structure, a method of rotating the inlet section of the transition portion by 60 degrees to the main flow incoming direction (reverse direction of the Z axis) is adopted.
Specifically, the bridge of the self-circulation processing casing can be divided into three independent bridge channels with smaller flow areas by using two built-in baffles, and the baffles can be removed to design the bridge channels with larger flow areas. When the bridge is designed as a channel with a larger flow area by removing the baffle plates, the static pressure of the air flow at the outlets of the three air entraining sections is required to be approximately equal, otherwise, due to the difference between the static pressure values of the three independent air entraining sources, the phenomenon of countercurrent or non-circulation of the air entraining sources with lower static pressure can occur.
Specifically, the method for ensuring that the static pressure of the air flows of the outlets of the three bleed air sections is approximately equal is to adjust the area of the outlets of the bleed air sections so as to achieve the purpose of controlling the static pressure of the air flows of the outlets of the three bleed air sections to be approximately equal. The specific calculation process is as follows: existing Bernoulli equation (equation 1) and conservation of mass equation (equation 2)
ρ in A in v in ＝ρ out A out v out (2)
Wherein, the subscript "in" represents the connection section of the air entraining section of the self-circulation structure and the jet flow groove, the subscript "out" represents the connection section of the air entraining section of the self-circulation structure and the bridge passage, and the ρ is considered as in ＝ρ out . The total airflow pressure of a certain bleed section of the circulating structure can be measured, and after the static pressure value of the outlet airflow of the bleed section is determined, the airflow velocity v of the cross section of the bleed section connected with the bridge can be calculated by the formula (2) out . Calculating the connection cross-sectional area A of the air entraining section and the bridge according to the formula (1) out And finally, ensuring that the static pressure of air flow at the outlets of the three air entraining sections is approximately equal.
Specifically, referring to fig. 1, the jet section is designed by Coanda curve, the throat height is 0.16mm, the included angle between the jet direction of the circulating air flow and the main flow is 10 degrees, the axial distance of the jet port is 3mm, the circumferential coverage rate is 12.5%, and the axial position of the tail edge of the jet port is the same as the axial position of the front edge of the rotor blade top.
In the compressor of the embodiment, 20 self-circulation structures are arranged in the full circumferential range, and the number of the self-circulation structures is the same as that of the static blades.
The above technical scheme is further described below through specific experiments.
Referring to fig. 1 to 6, in the flow control method for coupling a novel blade slotting and a self-circulation processing casing according to the embodiment, the air-entraining position of the self-circulation structure is arranged above a stator blade channel, three jet slots are formed in the stator blade, radial baffles are arranged in the jet slots, an air-entraining port of the self-circulation processing casing is connected with the top end of the jet slot of the stator blade, and the axial position of the tail edge of the air-entraining port is the same as the axial position of the front edge of the blade top of the rotor. In addition, the self-circulation structure is circumferentially arranged with 20, which is consistent in the number of blades. The novel flow control method for coupling blade slotting with the self-circulation processing casing has the advantages that: on one hand, because the pressure difference exists on the suction pressure surface of the stator blade, the jet flow promotes the kinetic energy of low-speed fluid on the suction surface of the stator blade, enlarges the effective flow area, effectively reduces the flow loss in the channel of the stator blade, and improves the efficiency of the compressor; on the other hand, the self-circulation structure can suck partial air flow from the stator blade channel by using the baffle plate in the jet slot and jet the partial air flow in the rotor blade top channel so as to increase the kinetic energy of low-speed fluid in the rotor blade top channel and achieve the aim of improving the stability of the air compressor.
A novel flow control method based on the coupling of blade slotting and self-circulation processing casing of a single-stage subsonic axial flow compressor is characterized by comprising the following steps:
step one: three jet flow grooves are formed in the static blade of the air compressor, and the axial positions of the outlets of the jet flow grooves are as follows: 15% Ca, 50% Ca and 85% Ca (Ca represents the axial chord length of the stator blade tip), each groove has a width of 8% Ca (which can be selected from the range of 8% Ca to 13% Ca), and the radial range of the jet grooves has a blade height of 25% to 100% (the radial range can be selected and designed according to the separation degree of the boundary layers of different blade high sections).
Step two: an air flow baffle is arranged in the jet flow groove, so that partial jet flow is sucked into the self-circulation structure by the air entraining port under the action of the baffle. The larger the radial range of the baffle plate is, the larger the flow of the circulating airflow is, and the lower the jet flow is; the smaller the radial extent of the baffle, the smaller the flow of the circulating gas stream and the higher the jet flow.
Step three: the axial position of the front edge of the air jet of the self-circulation structure is the same as that of the front edge of the rotor blade top. The self-circulation structure jet section line is designed by adopting a Coanda curve, the throat height is 0.16mm, the jet angle is 10 degrees, and the distance between the suction surface and the pressure surface of the jet port is 3mm. .
Step four: and designing the air entraining section of the self-circulation structure according to the maximum height of the air injecting section of the self-circulation structure. To ensure that the static pressure of the connecting sections of the three bleed air sections and the bridge is the same, the corresponding bleed air section outlet cross-sectional area is calculated according to Bernoulli equation (formula 1) and mass conservation equation (formula 2). The transition part of the air flow direction of the air entraining section adopts an arc design, and the rotation angle is 60 degrees.
Step five: and horizontally extending an inlet molded line of the jet section of the self-circulation structure to the direction of the static blade to form a bridge, wherein the length of the bridge is 50mm.
Step six: the direction transition part of the bleed air section is connected with the inlet section of the bridge by a straight line, and finally a complete airflow passage is formed.
Step seven: the self-circulation structures generated in the first to sixth steps are circumferentially arranged in 20 numbers and are consistent with the number of the static blades.
The invention is applied to a single-stage subsonic axial flow compressor of northwest industrial university, and main parameters of the compressor are shown in table 1.
TABLE 1 design parameters for single stage subsonic axial flow compressor at northwest industrial university
The experimental method takes a single-stage subsonic axial flow compressor of northwest industrial university as a research object, and develops unsteady numerical simulation research of a novel flow control method of blade slotting and self-circulation processing casing coupling, and the implementation process is as follows:
1. and (3) carrying out structural grid division on the grid of the blade channels of the air compressor by using an Autogrid5 module of the NUMECA software installation package.
2. And (3) meshing the stator blade jet grooves and the self-circulation structure by using an IGG module of the NUMECA software installation package.
3. The method comprises the steps of carrying out numerical calculation by using a Fine-Turbo module of a NUMECA software installation package, carrying out full three-dimensional calculation on a generated numerical calculation grid by using a Euranus solver, and specifically configuring that the rotating speed of a rotor of a gas compressor is 10765r/Min (70% of design rotating speed), a space discrete format of a control equation adopts a symmetry TVD scheme of a second-order windward format, an oscillation limit type of a linear domain and nonlinear domain numerical solution selects a MinMod format, time discrete of the control equation adopts a fourth-order range-Kutta method, unsteady calculation adopts a double-time-step propulsion method, the number of physical time steps of the rotor rotating through a blade grid channel is set to be 20, and 20 virtual time steps are set under each physical time step. And the convergence rate is increased by adopting a multi-grid method, a local time step, implicit residual error fairing and other methods.
4. And acquiring a numerical value calculation result by using a CFView module of the NUMECA software installation package, and performing data processing. And taking the gas compressor prototype as a reference, and obtaining the comprehensive stall margin improvement quantity and the efficiency improvement quantity of the static blade suction type self-circulation processing casing.
The research results show that: the comprehensive stall margin high improvement amount of the novel flow control method of blade slotting and self-circulation processing casing coupling is 3.7%, and the isentropic efficiency absolute amount of the compressor is improved by 1.1% under the near stall working condition. The novel flow control method of blade slotting and self-circulation processing casing coupling can improve the stable working margin of the compressor and greatly improve the isentropic efficiency of the compressor under the near stall working condition.
Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations may be made in the above embodiments by those skilled in the art without departing from the spirit and principles of the invention.
Claims (10)
1. A novel flow control method for coupling blade slotting and self-circulation processing cases is characterized by comprising the following specific steps:
jet grooves are formed in the stator blades;
a deflector is arranged in the jet flow groove to split jet flow entering from the inlet of the jet flow groove;
a self-circulation structure is arranged between the jet flow groove and the rotor blade top;
under the action of the pressure difference of the suction surface and the pressure surface of the static blade, the self-adaptive jet flows in from an inlet on the pressure surface side of the jet flow groove, flows through the guide plate, and a part of the self-adaptive jet flows to the top of the jet flow groove under the action of the guide plate, enters a self-circulation structure and finally flows into a main flow channel at the top of the rotor blade; the other part of the self-adaptive jet flows out from an outlet on the suction surface side under the action of a guide plate.
2. The method of flow control for a novel vane slot and self-circulating process cartridge of claim 1, wherein: the method for splitting the jet flow by the guide plate is that the guide plate is obliquely arranged in the jet flow groove, the position height of one end of the guide plate near the suction surface is set to be larger than the position height of one end of the pressure inlet surface, and the split flow of the two parts is controlled by adjusting the inclination; when the inclined direction of the guide plate is closer to the radial direction, the airflow flowing into the self-circulation structure is increased, and the airflow flowing out of the suction surface is reduced; when the inclined direction of the deflector is closer to the axial direction, the airflow flowing into the self-circulation structure is reduced, and the airflow flowing out of the suction surface is increased.
3. Novel flow control structure of blade fluting and coupling of self-loopa processing machine casket, its characterized in that: the flow control method for implementing the novel blade slotting and self-circulation processing casing coupling of claim 1 or 2, comprising a jet slot arranged on the stator blade and used for communicating a pressure surface and a suction surface, a guide plate arranged in the jet slot and used for controlling flow, and a self-circulation structure used for communicating the jet slot and a rotor blade top;
the jet flow is introduced into the inlet at the pressure surface side of the jet flow groove, flows through the guide plate, and a part of jet flow flows to the top of the jet flow groove under the action of the guide plate, enters a self-circulation structure and finally flows into the main flow channel at the top of the rotor blade; the other part of jet flows out from the outlet on the suction surface side under the action of the guide plate.
4. A novel vane slotting and self-circulating processing casing coupled flow control structure as claimed in claim 3, wherein: three jet grooves are arranged on the static blade, and the radial positions of the three jet grooves are in a 25% -100% blade height range; the entrance of the jet slot is positioned at the pressure surface side, and the width is 8 percent Ca; the jet flow groove outlet is positioned on the suction surface side, and the width is 5% Ca.
5. A novel vane slotting and self-circulating processing casing coupled flow control structure as claimed in claim 3, wherein: the near suction face one end of guide plate is installed in leaf top department, and the radial height of near pressure face one end can be adjusted according to the flow demand.
6. The flow control structure of claim 5, wherein the flow control structure is coupled to the self-circulating processing casing and comprises: the height of the guide plate is adjustable, and the lower the radial height of the guide plate is, the more air flows into the self-circulation structure, the less air flows out of the suction surface; the higher its radial position, the less airflow flows into the self-circulating structure and the more airflow flows out of the suction side.
7. A novel vane slotting and self-circulating processing casing coupled flow control structure as claimed in claim 3, wherein: the self-circulation structure comprises an air-entraining section, a bridge circuit and an air-jetting section which are sequentially arranged, wherein an air-entraining port of the air-entraining section is positioned in the radial extending direction of the jet flow groove and is communicated with an opening at the top of the jet flow groove, and jet flow in the jet flow groove, which is split by a guide plate, is led into the self-circulation structure; the bridge extends along the direction of the rotor facing the casing wall, the air-entraining end introduces jet flow into the bridge through the transition section, and the inlet section of the transition section rotates 60 degrees towards the main flow incoming direction to obtain the outlet section connected with the bridge; the inlet of the air injection section is connected with the outlet of the bridge, and the nozzle faces the front edge of the blade top of the rotor.
8. The flow control structure of claim 7, wherein the vane slot is coupled to the self-circulating processing casing, and wherein: the bridge channels are separated by built-in baffles and are divided into bridge channels which are in one-to-one correspondence with the number of jet flow grooves and air entraining sections;
or the channels in the bridge are integral channels, and jet flows of a plurality of air entraining sections are converged; by adopting the integral channel, the air flow static pressure at the outlets of the three air entraining sections is required to be ensured to be approximately equal, otherwise, due to the difference between the static pressure values of the three independent air entraining sources, the air entraining sources with lower static pressure can have the phenomenon of countercurrent or non-circulation.
9. The flow control structure of claim 7, wherein the vane slot is coupled to the self-circulating processing casing, and wherein: the jet section is designed by adopting a Coanda curve, the throat height is 0.16mm, the included angle between the jet direction of the circulating airflow and the main flow is 10 degrees, the axial distance of the jet port is 3mm, the circumferential coverage rate is 12.5%, and the axial position of the tail edge of the jet port is the same as the axial position of the front edge of the rotor blade top.
10. A compressor, characterized in that: a flow control structure comprising the novel vane slot of any one of claims 3-9 coupled to a self-circulating processing casing, the number of flow control structure being identical to the number of vanes and being arranged in a one-to-one correspondence.
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| CN202311373052.9A CN117588444A (en) | 2023-10-23 | 2023-10-23 | Flow control method and structure for coupling blade slotting and self-circulation processing casing |
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| CN202311373052.9A CN117588444A (en) | 2023-10-23 | 2023-10-23 | Flow control method and structure for coupling blade slotting and self-circulation processing casing |
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