Rectifier, flow passage structure, combined compressor, aero gas turbine engine
Technical field
Embodiments of the invention relate to aeroengine field, particularly relate to there is negative cruvature runner rectifier, combined compressor flow passage structure, there is the combined compressor of this flow passage structure and there is the aero gas turbine engine of this combined compressor.
Technical background
All adopt the multi stage axial flow compressor structural type of large discharge, high pressure ratio different from high thrust aeroengine, combined compressor is the main structure pattern of middle low thrust aeroengine compression system.
Axial flow+centrifugal combined compressor combines that axial flow runner is level and smooth, efficiency is high, and the feature that centrifugal level flow is little, operating range is broad, part is few and reliability is high, is widely used in the aero gas turbine engine of medium-small flow.
For modern high performance axial flow+centrifugal combined compressor, inter-stage usually adopts and designs without changeover portion.Owing to eliminating changeover portion, the axial length of combined compressor is shorter, and efficiency is higher.But bring certain difficulty also to axial flow level, the respective optimization of centrifugal level and both couplings without the design of changeover portion.For axial flow level, needing, by raising axial-flow blower outlet diameter, to increase its acting ability, realizing higher single-stage pressure ratio, thus the component number of minimizing gas compressor, weight and manufacture cost; And for centrifugal impeller, require large inlet area, little entrance Mach number and little entrance hub diameter, to ensure that centrifugal level has higher efficiency and surge margin, it is contradiction that this and axial flow level export larger hub ratio, and the reduction of axial flow level rectifier outlet hub diameter can bring the rising of axial flow level rectifier root load, being separated and losing the adverse effects such as larger appears in flowing.
Therefore, the novel compositions compressor passage structure that exploration one has taken into account the double requirements of axial flow compressor high outlet/entrance mean radius ratio (strengthening acting ability) and centrifugal compressor low entry hub ratio is needed badly.
Summary of the invention
In order to overcome the problem that single-stage pressure ratio is low, progression is many, weight is large, manufacture cost is high existing for existing middle-size and small-size aero gas turbine engine employing multistage axial flow or axial-flow-centrifugal combined compressor, the present invention is proposed.
An aspect according to an embodiment of the invention, proposes a kind of rectifier with negative cruvature runner, and the entrance of described rectifier is suitable for communicating with axial flow compressor, and outlet is suitable for communicating with centrifugal compressor, and described rectifier comprises: inner ring surface; Outer ring surface; Be arranged on the negative cruvature runner between inner ring surface and outer ring surface, described negative cruvature runner is made up of multiple negative cruvature pipeline, and pipeline is uniform in a circumferential direction and be spaced apart from each other and be spaced apart from each other and the outlet stream area of each pipeline falls in the scope of 1.2 ~ 1.4 with the ratio of entrance circulation area.
Alternatively, the sectional shape of described pipeline is circle, oval or class is oval.
Alternatively, the angle of the center line of each pipeline and the spin axis of axial flow compressor is 25 ° ~ 45 °; The non-dimensional ratio L/H of each pipeline is less than 1.5, and wherein, L is the axial length of pipeline, and H is the radial height of pipe outlet.
According to an embodiment of the invention on the other hand, also proposed a kind of flow passage structure of combined compressor, comprising: as the single-stage axial compressor of the first order, there is axial-flow blower; There is the rectifier of negative cruvature runner; Centrifugal compressor with as the second level, has centrifugal impeller, wherein: described rectifier is above-mentioned rectifier; The entrance of each pipeline and the outlet of axial flow compressor, the outlet of each pipeline is communicated with centrifugal compressor; Axial-flow blower entrance mean radius is less than the entrance mean radius of pipeline, and the outlet mean radius of pipeline is less than the entrance mean radius of pipeline.
Alternatively, the number of described pipeline is 1.5 ~ 2 times of the axial-flow blower number of blade.
Alternatively, the number of described pipeline is 1.5 ~ 2 times of centrifugal impellers blades number.
Alternatively, the outlet of described pipeline is along the circumferential direction upper relative to the entrance of described pipeline to be offset, and offset direction is consistent with the sense of rotation of axial-flow blower.
Embodiments of the invention also relate to a kind of combined compressor, comprising: rotating shaft; The flow passage structure of above-mentioned combined compressor; Be arranged on the radial diffuser in centrifugal impeller downstream; And be arranged on the axial Diffuser in radial diffuser downstream, wherein, the axial-flow blower of described combined compressor and centrifugal impeller axis around the shaft rotates.
Embodiments of the invention also relate to a kind of aero gas turbine engine, comprise above-mentioned Combined press mechanism of qi.
Based on the combined compressor of technological scheme of the present invention, have simple and compact for structure, component are few, rotor length is short and the processing advantages such as maintenance cost is low.
Accompanying drawing explanation
Fig. 1 is the runner schematic diagram with the combined compressor of negative cruvature pipe type rectifier of one embodiment of the present of invention.
Fig. 2 is the 3 D stereo schematic diagram with the combined compressor of negative cruvature pipe type rectifier of the present invention.
Description of reference numerals: axial-flow blower 1, rectifier 2, centrifugal impeller 3, radial diffuser 4, axial Diffuser 5, gas compressor rotating shaft 6.
Embodiment
Below by embodiment, and by reference to the accompanying drawings, technological scheme of the present invention is described in further detail.In the description, same or analogous drawing reference numeral indicates same or analogous base member.The explanation of following reference accompanying drawing to embodiment of the present invention is intended to make an explanation to present general inventive concept of the present invention, and not should be understood to one restriction of the present invention.
As shown in Figure 1, the present invention proposes a kind of rectifier 2 with negative cruvature runner, the entrance of described rectifier 2 is suitable for communicating with axial flow compressor (representing with axial-flow blower 1 in FIG), and outlet is suitable for communicating with centrifugal compressor (representing with centrifugal impeller 3 in FIG).See Fig. 1 and Fig. 2, rectifier 2 comprises: inner ring surface 21; Outer ring surface 22; Be arranged on the negative cruvature runner between inner ring surface and outer ring surface, negative cruvature runner is made up of multiple negative cruvature pipeline 23, pipeline 23 is uniform in a circumferential direction and be spaced apart from each other and the outlet stream area of each pipeline 23 falls in the scope of 1.2 ~ 1.4 with the ratio of entrance circulation area, such as this ratio can be 1.2,1.25,1.3,1.35,1.4, to realize air-flow maximal integer mass flow under the unseparated prerequisite that flows in guarantee rectifier.
Utilize this rectifier 2, the uniform stream of the in the future axial flow compressor of self-rectifying device upstream can be distributed to the centrifugal compressor in rectifier downstream.
Blade type rectifier is adopted in prior art, but Curvature varying is large, difficulty of processing is large problem that this blade type rectifier exists, and also there is airflow breakaway at the root of blade, and pipe type negative cruvature rectifier of the present invention to have structure simple, processing cost is low, avoid negative cruvature runner lower blade root separation problem simultaneously, can at utmost improve rectifier performance.
Rectifier can be formed from steel, and particularly, in the steel loop with negative cruvature, between inner ring surface and outer ring surface, directly can get out pipeline.Rectifier also can be made into integration by casting technique.
Alternatively, the sectional shape of described pipeline is circle, oval or class is oval.So, each pipeline intersecting shape becomes dove-tail form leading edge, can adapt to axial-flow blower better and export uneven incoming flow, improves rectifier performance.
As shown in Figure 1, alternatively, the angle theta of the center line of each pipeline and the spin axis of combined compressor is 25 ° ~ 45 °, the non-dimensional ratio L/H of each pipeline is less than 1.5, to ensure that rectifier has higher total pressure recovery performance and exit flow field uniformity, wherein, L is the axial length of pipeline, and H is the radial height of pipe outlet.θ can be 25 degree, 30 degree, 45 degree.
Correspondingly, present invention also proposes a kind of flow passage structure of combined compressor, as shown in Figure 1, this flow passage structure comprises: as the single-stage axial compressor of the first order, has axial-flow blower 1; The above-mentioned rectifier 2 with negative cruvature runner; With the centrifugal compressor as the second level, have centrifugal impeller 3, wherein: the entrance of each pipeline 23 and the outlet of axial flow compressor, the outlet of each pipeline 23 is communicated with centrifugal compressor; And axial-flow blower entrance mean radius R1 is less than the entrance mean radius R2 of pipeline, the outlet mean radius R3 of pipeline is less than the entrance mean radius R2 of pipeline.
As shown in Figure 1, runner first lifting gradually from entrance of axial flow compressor, making axial-flow blower entrance mean radius R1 be less than the entrance mean radius R2 of pipeline, can increase acting ability by raising axial-flow blower outlet flow external diameter; The outlet mean radius R3 of pipeline 23 is less than the entrance mean radius R2 of pipeline 23, and this can effectively reduce Centrifugal Impeller Inlet hub ratio, adapts to the requirement of centrifugal compressor entrance, reduces centrifugal compressor design difficulty.
Because the passage between the outlet of pipeline 23 and the blade of centrifugal impeller communicates, and the discharge area of pipeline 23 is greater than the inlet area of pipeline 23, therefore, preferably, also considers the relation between the number of pipeline 23 and centrifugal impellers blades number.Alternatively, the number of pipeline 23 is 1.5 ~ 2 times of axial blade number, such as, be 1.5 times, 2 times or 1.7 times of axial blade number.When pipeline 23 is along the circumferential direction uniform, this can ensure that rectifier has higher total pressure recovery performance and exit flow field uniformity.
In order to reduce flow losses, alternatively, the outlet of pipeline 23 offsets in a circumferential direction relative to the entrance of pipeline 23, and offset direction is consistent with the sense of rotation of axial-flow blower.Such as, in fig. 2, when the blade of axial impeller 1 rotates in the clockwise direction, the outlet of pipeline 23 offsets in the clockwise direction relative to entrance.
According to the flow passage structure of combined compressor of the present invention, one of the advantage at least as follows relative to traditional combined compressor runner layout can be obtained: 1. the single-stage pressure ratio of axial flow compressor is higher, gas compressor component number can be made greatly few, simple and compact for structure, obviously reduce processing, install and maintenance cost; 2. earlier stages adopts high pressure ratio single-stage axial compressor to replace multi stage axial flow compressor and shortens supporting span, reduces shafting design difficulty; 3. the axial flow that earlier stages adopts wide string to design distortion tolerance of calming the anger is high, and anti-foreign object strike ability (FOD) is strong, and the reynolds' number simultaneously based on blade chord length improves, under the low reynolds number condition of high-altitude, have higher performance.
As shown in Figure 1, present invention also proposes a kind of combined compressor, comprising: rotating shaft 6; The flow passage structure of above-mentioned combined compressor; Be arranged on the radial diffuser 4 in centrifugal impeller downstream; And be arranged on the axial Diffuser 5 in radial diffuser 4 downstream, wherein, the axial-flow blower of described combined compressor and centrifugal impeller axis around the shaft rotates.
The operation of combined compressor is described below.During combined compressor work, axial-flow blower 1 and centrifugal impeller 3 rotate around gas compressor axis 6, air-flow introduces axial-flow blower 1 by inlet casing, after axial-flow blower 1 supercharging, flows into rectifier 2 and carries out rectification, centrifugal impeller 3 is entered after rectification diffusion, after centrifugal impeller 3 further supercharging, enter blade type radial diffuser 4, supercharging of slowing down wherein, pass through the rectification further of axial Diffuser 5 again, last flowing in combustion chamber.
Axial-flow-centrifugal combined compressor according to the present invention has large bow-backed type runner, the double requirements of axial flow compressor height acting ability and the low hub ratio of centrifugal compressor can be taken into account, because single-stage axial compressor has higher level pressure ratio, therefore, the multi stage axial flow compressor before axial-flow-centrifugal combined compressor can be replaced, gas compressor component number is greatly reduced, simple and compact for structure, obviously reduce processing, install and maintenance cost.
Aero gas turbine engine can be applied to, especially the middle-size and small-size aero gas turbine engine of high-performance according to combined compressor of the present invention.
Although illustrate and describe embodiments of the invention, for the ordinary skill in the art, be appreciated that and can change these embodiments without departing from the principles and spirit of the present invention, scope of the present invention is by claims and equivalents thereof.