Summary of the invention
The centrifugal compressor that provides a kind of diffuser vane to vibrate is provided the problem that the present invention solves, can effectively improve the separation of unit internal flow characteristics, minimizing flow process, the scope of expansion steady working condition, make impeller mate and control with mobile being optimized between Diffuser.
The present invention is achieved through the following technical solutions:
The centrifugal compressor that a kind of diffuser vane can vibrate, comprise suction chamber, impeller, Diffuser, bend, return channel and volute casing, it is characterized in that, in Diffuser, be provided with water conservancy diversion diffuser vane, diffuser vane is connected with dividing plate by diffuser vane running shaft;
Vibration exciter is connected with diffuser vane by driving mechanism, produces vibration when vibration exciter is worked, and passes to diffuser vane, and diffuser vane, around the vibration of diffuser vane running shaft, carries out ACTIVE CONTROL to Diffuser flow field;
Or diffuser vane is connected with elastic element by driving mechanism, in Diffuser, there is gas flow out-of-date, diffuser vane produces self oscillations, realizes Diffuser interior flow field is carried out to self adaptive control.
Describedly by vibration exciter or elastic element, make diffuser vane produce integral oscillation, by the vibration of diffuser vane, improve the aeroperformance of Diffuser.
Describedly by vibration exciter, Diffuser flow field is carried out to ACTIVE CONTROL, during diffuser vane integral oscillation, the maximum deflection angle of diffuser vane is 10 °.
The frequency of okperation of described vibration exciter is 0.5f
n~5f
n, f
nthe frequency of lift coefficient vibration during for the stall of stationary diffuser Static Leaf.
Describedly by vibration exciter, Diffuser flow field is carried out to ACTIVE CONTROL, pitching movement during diffuser vane integral oscillation is described as α (t)=α
0+ α
asin(ω t), wherein α is diffuser vane deflection angle, and t is the time, α
0for diffuser vane initial deflection angle, α
afor the angle of vibration deflection, the frequency of okperation that ω is vibration exciter.
Described while Diffuser flow field being carried out to self adaptive control by elastic element, the intensity of elastic element is determined by the suffered gas force of diffuser vane and diffuser vane maximum deflection angle.
Described diffuser vane running shaft is arranged on the place, pressure center of diffuser vane.
Compared with prior art, the present invention has following useful technique effect:
1) compare with traditional diffuser structure, the centrifugal compressor that diffuser vane provided by the invention can vibrate is in the flow field constantly changing, blade vibrates around the shaft a little, thereby the variation that can effectively make runner be adapted to flow, reduce the separation in flowing, reduced energy loss, improved the overall performance of Diffuser, and in the situation that changing operating mode, reduced the possibility that blade path generation flow shedding causes rotating stall, thereby in the generation that has fundamentally reduced surge.
2) centrifugal compressor that diffuser vane provided by the invention can vibrate, the Diffuser with blade integral oscillating structure has simple in structure, compact, the feature of successful.When adopting vibration exciter scheme, by additional vibration system, carry out ACTIVE CONTROL, can pass through to change fast the vibration frequency of actuator, thereby effectively control the blade vibration in Diffuser, and then improve flow condition, to adapt to the requirement of different operating modes.When adopting Flexible element scheme, except structure own is very simple, as a kind of self-adaptation control method, can not need to carry out again subsequent operation, for production practices, more simple and convenient.The utilization of these controlling methods, with respect to other controlling method, has its incomparable advantage.
3) with respect to the mobile control of other parts of compressor, the for example profile setting of impeller, the variations such as blade cracks, the centrifugal compressor that diffuser vane provided by the invention can vibrate, the structure optimization of Diffuser makes to vibrate a little on blade integral, with respect to local optimization and control, the effect reaching is more obvious.
4) centrifugal compressor that diffuser vane provided by the invention can vibrate, also there is very high Security, because being realizes the integral oscillation to blade by employing distinct methods, the structure of blade itself and profile are not processed, for example blade cracks, perforate, changes profile etc., and therefore the mechanics for blade itself requires not impact.Meanwhile, owing to having reduced the generation possibility of surge, can, to the safety of compressor and steady production, play actively significant impact.
The present invention is directed to Efficiency Decreasing under the variable working condition of the existence in the middle of vane diffuser operation, thereby the easily separated relevant feature such as surge that cause flow, on the basis of proposition on traditional diffuser vane, by adopting different flow control methods, realize the vane diffuser structure of diffuser vane integral oscillation.Finally can effectively improve the separation of unit internal flow characteristics, minimizing flow process, the scope of expansion steady working condition, and provide new approach for realizing the efficient utilization of whole compressor.
By application of the present invention, can effectively improve the manufacturing efficiency of centrifugal compressor, expand steady working condition, reduce the consumption of the energy, when meeting develops relevant industrial field and national economy produces promoting effect, also can improve the development of the technology of compressor association area.
Embodiment
Below in conjunction with specific embodiment, the present invention is described in further detail, and the explanation of the invention is not limited.
The centrifugal compressor that diffuser vane provided by the invention can vibrate, is a kind of blade integral oscillating type Diffuser, makes impeller mate and control with mobile being optimized between Diffuser, thereby expands steady working condition scope and raise the efficiency.For the Efficiency Decreasing under the variable working condition existing in the middle of vane diffuser operation, thereby runner is the separated relevant feature such as surge that cause easily, proposed on the basis on traditional diffuser vane, by adopting various flows flowing control method, comprise active and adaptive approach, realize the integral oscillation of diffuser vane, thereby can effectively postpone flow separation, reduce separated region and flow losses.Meanwhile, the flow stability under variable working condition is greatly improved, has expanded the scope of steady working condition, effectively reduced the generation of rotating stall, thereby in root, suppressed compressor and occurred surge, finally reached and improved diffuser performance, the object of raising the efficiency.
The present invention is mainly by adopting two kinds of different technological schemes to realize the integral oscillation of diffuser vane:
The centrifugal compressor that a kind of diffuser vane can vibrate, comprise suction chamber, impeller, Diffuser, bend, return channel and volute casing, it is characterized in that, in Diffuser, be provided with water conservancy diversion diffuser vane, diffuser vane is connected with dividing plate by diffuser vane running shaft;
Vibration exciter is connected with diffuser vane by driving mechanism, when working, vibration exciter produces vibration, pass to diffuser vane, diffuser vane vibrates around diffuser vane running shaft, Diffuser flow field is carried out to ACTIVE CONTROL (by adopting external vibration rod system to carry out constrained vibration to diffuser vane, this is ACTIVE CONTROL);
Or, diffuser vane is connected with elastic element by driving mechanism, in Diffuser, there is gas flow out-of-date, diffuser vane produces self oscillations, realization is carried out self adaptive control (such as passing through connecting rod linking springs system at diffuser vane to Diffuser interior flow field, Gu diffuser vane produces self oscillations under stream-coupling, thereby the integral oscillation of acquisition blade is self adaptive control).
The centrifugal compressor that described diffuser vane can vibrate, makes diffuser vane produce integral oscillation by vibration exciter or elastic element, improves the aeroperformance of Diffuser by the vibration of diffuser vane.
Concrete is carrying out ACTIVE CONTROL by vibration exciter to Diffuser flow field, and during diffuser vane integral oscillation, the maximum deflection angle of diffuser vane is 10 °; The frequency of okperation of vibration exciter is 0.5f
n~5f
n, f
nthe frequency of lift coefficient vibration during for the stall of stationary diffuser Static Leaf.
Concrete when Diffuser flow field being carried out to self adaptive control by elastic element, the intensity of elastic element is determined by the suffered gas force of diffuser vane and diffuser vane maximum deflection angle; Described diffuser vane running shaft is arranged on the place, pressure center of diffuser vane.
In conjunction with Fig. 1, Fig. 2, Fig. 3, Fig. 4, provide following specific embodiment.
Embodiment 1
The present embodiment carries out the integral oscillation of blade by vibration exciter:
Vibration exciter is connected with diffuser vane by driving mechanism, produces vibration when vibration exciter is worked, and passes to diffuser vane, and diffuser vane, around the vibration of diffuser vane running shaft, carries out ACTIVE CONTROL to Diffuser flow field.Connecting rod is arranged in diffuser vane pilot hole below as main driving mechanism, and the gearing by connecting rod realizes diffuser vane is connected with vibration system.
Vibration exciter amplitude is 5mm, and vibration frequency changes between can be from 0Hz to 200Hz, when vibration exciter is when certain sets excited frequency, by connecting rod, excitation is delivered to blade, blade is vibrated a little, as Fig. 1, shown in Fig. 2 around pilot hole.By the double vibrations of vibration exciter, finally realize the whole constrained vibration of blade.This kind of mobile control that mode is a kind of active.
Embodiment 2
The present embodiment carries out the integral oscillation of blade by elastic element:
Diffuser vane is connected with elastic element by driving mechanism, has gas flow out-of-date in Diffuser, and diffuser vane produces self oscillations, realizes Diffuser interior flow field is carried out to self adaptive control.Concrete elastic element adopts spring, and connecting rod is arranged in diffuser vane pilot hole below as main driving mechanism, and the gearing by connecting rod realizes diffuser vane is connected with vibration system.Under the effect of the inner incoming flow of Diffuser, because Gu blade exists strong stream-coupling with air-flow in Diffuser, blade deflection drivening rod rotates the spring system that makes to be connected on connecting rod and deforms, and the distortion of spring finally reacts on blade structure, by connecting rod transfer function power, make blade deflection, and then changed flow condition, thereby realize the self oscillations that the blade of blade vibrates around the shaft a little.This kind of mode is a kind of self adaptive control.
The present invention by adopting various flows flowing control method, comprises initiatively and adaptive approach, realizes the integral oscillation of diffuser vane, thereby effectively improve the performance in flow field.In order to verify the good effect of blade integral vibration, by blade being installed around join, a little carry out a little oscillating process and carry out numerical simulation and analyze the blade impact of pitching movement on Diffuser interior flow field of vibrating.Here, by setting the rule of blade oscillatory movement, pitching blade motion be set be:
α(t)=α
0+α
Asin(ωt)
Wherein: wherein α is diffuser vane deflection angle, t is the time, α
0for diffuser vane initial deflection angle, α
afor the angle of vibration deflection, the frequency of okperation that ω is vibration exciter;
Concrete a
0=10 °, α
aget respectively 2 °, 6 °, 10 °; ω=2 π f.F gets 0.5fn, 2fn, 5fn, and fn is the frequency of vibrating when angle of attack=10 ° lift coefficient in static stall, can access from the curve of its lift coefficient and time.
In simulation process, having chosen reynolds' number is 10500, and airfoil fan is α at the initial angle of attack
0near state while doing integral oscillation pitching movement=10 °.And study by the pitching blade exercise data arranging under three groups of different frequencies and amplitude, and contrast with the blade movement situation under state of rest, by some result of calculations above, the integral oscillation that has obtained airfoil fan can slow down the fast development in the main whirlpool of leading edge and come off, there is significant effect in whirlpool, can effectively delay stall generation and improve the kinetic characteristic of blade in flow field.Coincide with the effect that integral oscillation formula diffuser vane presented above will reach.For different frequencies and the amplitude of extrinsic motivated, for the motion effects of blade, also done effective analysis, obtained optimum frequency and amplitude simultaneously.
Figure 5 shows that fixedly lift coefficient curve comparison figure (Re=10500, the α of airfoil fan and integral oscillation formula airfoil fan
0=10 °, α
a=6 °, f=2f
n), from figure, can find out significantly that the lift coefficient of integral oscillation formula airfoil fan increases significantly than stator blade, and can find out that the angle of attack of dynamic stall also increases than the angle of attack of static stall and stepped back a lot.What lift coefficient was played a major role is that the separated main whirlpool of leading edge stops time and the angle of attack scope of (being that staying of separated whirlpool is vertical) at Loads On Oscillating Wings.Therefore, whole vibrating type airfoil fan keeps higher lift coefficient at vibration processes.
Figure 6 shows that the face upward evolution situation of stage vortex structure of airfoil fan, (Re=10500, α
0=10 °, α
a=10 °, f=2f
n), in the stage of facing upward, when angle of attack=7.43 °, integral oscillation formula airfoil fan surface fluidal texture is Laminar Flow, at blade upper surface, streamline passes wall from blade inlet edge, penetrates wall again from trailing edge, this shows that airfoil fan wall fluid is moving with wall, and flows to trailing edge from leading edge.Along with the angle of attack increases to α=10.293 °, there is separated whirlpool and start to be shed in tail in trailing edge now.When the angle of attack increases to α=16.83 °, blade inlet edge starts to occur separated whirlpool.During in angle of attack=18.87 °, the eddy structure yardstick of blade surface is just larger, occurs the whirlpool of large scale, but does not come off.
Figure 7 shows that the evolution situation of airfoil fan nutation stage vortex structure, (Re=10500, α
0=10 °, α
a=10 °, f=2f
n), in the whole nutation stage, integral oscillation formula airfoil fan surface fluidal texture presents adhering to of large scale whirlpool and comes off, though at nutation the angle of attack in the stage less in, large scale eddy also exists.When the angle of attack reduces to α=17.03 °, there is secondary vortices structure in blade inlet edge, and along with the reducing gradually of the angle of attack, the whirlpool of the large scale of blade surface starts to come off gradually afterwards, until during α=3 °, the large scale eddy of blade surface is just shed in tail completely.
Figure 8 shows that the lift coefficient curve of different frequency oscillating airfoil blade under the different angles of attack (angle of blade and air-flow), wherein (a) angle of attack is 2 °, (b) angle of attack is 6 °, (c) angle of attack is 10 °, can find out, under identical angle of attack amplitude, different vibration frequencies, lift coefficient hysteresis loop wire shaped is different.In this example, frequency is larger, and the lift coefficient under its corresponding angle of attack is larger.
While Figure 9 shows that various amplitude, the lift coefficient curve of oscillating airfoil blade, (chooses Re=10500, α
0=10 °, f=0.5f
n), the amplitude in the time of angle of attack variation is also for affecting another important parameter of integral oscillation formula airfoil fan dynamic stall characteristic.As can be seen from Figure 9, under same frequency, the shape of the hysteresis loop curve of the lift coefficient of various amplitude is also different, in up process, amplitude is larger, lift coefficient under the same angle of attack is larger, but when amplitude is 6 ° and 10 °, the difference of the lift coefficient under the identical angle of attack is relatively a little bit smaller.In descending process, amplitude is larger, and the lift coefficient under the same angle of attack changes little, changes large angle of attack region also near the static stall angle of attack.
Table 1 is the average lift coefficient Cl under different frequency and amplitude, can obviously find out, for frequency from table 1, when frequency f=0, no matter amplitude is much, and reality is the circumferential motion problem of static airfoil fan, so lift coefficient is all the lift coefficient of static airfoil fan; Along with the increase of frequency, average lift coefficient, also along with increase, that is to say, in got frequency range, frequency is larger, and the average lift coefficient of blade is also larger, becomes positive correlation.For amplitude, same, when amplitude is zero, reality is streamed for static airfoil fan, and lift coefficient is all the lift coefficient under the static angle of attack.From table 1, also can find out, along with the increase of amplitude, average lift coefficient, also along with increase, that is to say, in got amplitude range, amplitude is larger, and the average lift coefficient of blade is also larger, becomes positive correlation.
Average lift coefficient C under table 1 different frequency and amplitude
l(Re=10500, α
0=10 °)
Above content is in conjunction with concrete preferred implementation further description made for the present invention; can not assert that the specific embodiment of the present invention only limits to this; for general technical staff of the technical field of the invention; do not departing under the prerequisite of the present invention's design (realizing the integral oscillation of diffuser vane); can also make some simple deduction or replace, all should be considered as belonging to the present invention and determine scope of patent protection by submitted to claims.