CN106570254B - Design method based on the anti-knock backhaul architecture in complete CCW theory circular passage - Google Patents
Design method based on the anti-knock backhaul architecture in complete CCW theory circular passage Download PDFInfo
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Abstract
The invention discloses a kind of design methods based on the anti-knock backhaul architecture in complete CCW theory circular passage, incident shock Propagation first, first segment is encountered to turn back face AB, it is reflected in wall surface, incident shock Mach 2 ship 1.6, first segment turn back face starting wedge surface angle be 25 °, incident shock encounters second segment and turns back face BC, it is reflected in wall surface, incident shock Mach 2 ship 1.913, the turn back starting wedge surface angle in face of second segment is 35 °, is turned back face CN when incident shock encounters third section, it is reflected in wall surface, incident shock Mach number Mw2Be 2.31, third section turn back face starting wedge surface angle be 30 °.Shock strength at annular channel outlet of the present invention is than original incident shock wave enhancing 68.1%, compared with 90 ° of prominent type annular channels of directly turning back, the shock wave focus moment is advanced by 8 μ s, and surge pressure of the concave surface bottom of chamber portion caused by shock wave focus and peak temperature improve 76.5% and 32.1%.
Description
Technical field
The invention belongs to the flow field controls of pulse-knocking engine research field and explosion-proof seismic wave to return technology, and in particular to
A kind of anti-knock backhaul architecture in circular passage based on complete CCW theory is designed, purpose is returned for controlling flow field and explosion-proof seismic wave
It passes.
Background technique
Pulse-knocking engine (Pulse Detonation Engine, abbreviation PDE) is a kind of new concept engine.It is quick-fried
Shake burning is different from common isobaric combustion.For the pressure and temperature of detonating combustion product than deflagration wave height, detonation wave speed is fast, and one
As 1000m/s magnitude.Compared to isobaric combustion, the thermal efficiency of detonating combustion is higher by 30%~40% or so.And PDE is opposite
It has many good qualities for conventional power plants.PDE structure is simple, light-weight, working range is wide, oil consumption rate is low, thrust ratio and
Specific impulse is big.
PDE needs the valve of quick response there is also the distance of DDT is longer at present, detonation tube when using liquid fuel
The problems such as size is larger low with detonation frequency.2001, Russian researchers Levin etc. proposed one kind and is referred to as later
Two-stage PDE(2-Stage Pulse Detonation Engine) novel PDE.It is reported that the working frequency of two-stage PDE can
Up to 24~25kHz, using operated pneumatic valve, without additional priming device, and the advantages that conventional liquid fuel can be used, compared with
Good solves the problems, such as that the PDE of traditional straight tube form exists.
However, there is also some problems for two-stage PDE.If detonation wave is after the intracavitary detonation in concave surface, ring can be passed through
On the one hand the upstream anti-pass of shape spout brings very big pressure fluctuation, easily cause level-one precombustion chamber flame-out；On the other hand, may be used
Can make the explosive mixture rich in activated group and intermediate product before entering concave surface chamber just burning totally, cause second it is quick-fried
Shake circulation can not carry out.Therefore, it is necessary to which the anti-knock passback mechanism of reliable design can just ensure that 2-stage PDE is continuous, high frequency
Work.
In fact, Prerry and Kantrowitz encountered this when studying the poly- heart of shock wave and colliding earliest early in nineteen fifty-one
A problem, using 90 ° of prominent transition channels.This scheme is not only without any theoretical foundation, and effect is very unsatisfactory.This
Kind of design structure has a significant impact to the uniformity of the SHOCK WAVE STABILITY after turning back and flow field after wave, it may appear that excessive pressure
Gradient and air-flow stagnation region, cause detonation wave preinitiation, directly influence the effect of shock wave focus.
Then, Takayama compares 90 ° of right angles and 6 kinds of faces of turning back with different-diameter rounded corner by testing, but by
In theoretical foundation deficiency, only it is difficult to find real optimal type face by limited test.
Later, Wu et al. was theoretical according to the CCW simplified, was carried out the incident direction of shock wave using three sections of face segmentations of turning back
It turns back, has received good effect.But he has carried out many simplification in calculating and design, such as, it is assumed that incident shock Mach
Number is infinitely great, this obviously has very big difference with actual conditions.In addition, his design is limited to the final outlet size in channel, because
There is no defer to CCW theory completely for this.
Therefore, a kind of circular passage based on complete CCW theory is designed, seems ten for steady flow condition and anti-knock passback
Divide important.
Summary of the invention
The object of the present invention is to provide a kind of design sides based on the anti-knock backhaul architecture in complete CCW theory circular passage
Method, for controlling flow field and the passback of explosion-proof seismic wave.
The technical scheme adopted by the invention is that
Design method based on the anti-knock backhaul architecture in complete CCW theory circular passage, it is characterised in that: including following step
It is rapid:
Step 1,
1.1 incident shock I firstoIt is axial to propagate to the right, when encounter first segment turn back face AB after, incident shock IoIn wall surface
It reflects, incident shock IoMach number MoIt is 1.6, first segment is turned back the starting wedge surface angle θ in face125 ° are taken as, according to following public affairs
Formula
Wherein, Mw0It turns back the Mach number that Mach is dry in face for first segment；
Unique solution M is obtained with the precision search of 8.5e-6 in root interval [ 1,3 ] using genetic algorithmw0=1.913；
1.2 by Mw0=1.913 substitute into following formula:
Obtain χ1=9.4357 °, wherein χ1It turns back the angle of three wave point tracks and wedge surface in face for first segment；It is namely incident
Shock wave by first segment turn back face during, three wave points will be along dotted line AA', with the track with the face AB at 9.4357 ° of angles
Move to A' point；In the process, Mach does Mw0Constantly increase, has arrived A' point, risen to circular passage A'B sections of height；
1.3 Mach of dry Mw0It will be as next section A'B' sections of incident shock I1Continuation downstream promotes, and intensity is compared with IoPhase
Than significantly improving；Better than the height MM'=200mm of flat segments, therefore, AA' sections of horizontal distance are as follows:
Step 2,
2.1 work as incident shock I1Second segment is encountered to turn back face BC, incident shock I1It is reflected in wall surface, incident shock I1
Mach number Mw0It is 1.913, second segment is turned back the starting wedge surface angle θ in face235 ° are taken as, according to the following formula
Wherein, Mw2Turn back the Mach number that Mach is dry in face for second segment, using genetic algorithm in root interval [ 1,3 ] with
The precision search of 8.5e-6 obtains unique solution Mw2=2.31；
2.2 by Mw2=2.31 substitute into following formula:
Obtain χ2=10.382 °, wherein χ2It turns back the angle of three wave point tracks and wedge surface in face for second segment；It is namely incident
Shock wave I1By second segment turn back face during, three wave points will be along dotted line BB', with the rail with the face BC at 10.382 ° of angles
Mark moves to B' point；In the process, Mach does Mw2Constantly increase, has arrived B' point, risen to circular passage B'C sections of height
Degree；
2.3 Mach of dry Mw2It will be as next section B'C' sections of incident shock I2Continuation downstream promotes, and intensity is compared with I1Phase
Than significantly improving；BB' sections along I1Length in incident direction are as follows:
In order to allow incident shock I1Stablize a distance, A'B sections along I1Incident direction on take 30mm；Likewise, in order to allow
Mw2Stablize and propagate a distance, takes B'C along I3Length on the direction of propagation is 30mm；
Step 3,
3.1 work as incident shock I2Third section is encountered to turn back face CN, incident shock I2It is reflected in wall surface, incident shock I2
Mach number Mw2It is 2.31, third section is turned back the starting wedge surface angle θ in face330 ° are taken as, according to the following formula
Wherein, Mw3Turn back the Mach number that Mach is dry in face for third section, using genetic algorithm in root interval [ 1,3 ] with
The precision search of 8.5e-6 obtains unique solution Mw3=2.81；
1.2 by Mw3=2.81 substitute into following formula:
Obtain χ3=11.7737 °, wherein χ3It turns back the angle of three wave point tracks and wedge surface in face for third section；Namely enter
Penetrate shock wave I2By third section turn back face during, three wave points will along dotted line CC', with the face CN at 11.7737 ° of angles
Track moves to N' point；In the process, Mach does Mw3Constantly increase, has arrived N' point；
3.3CC' sections along I3Length in incident direction are as follows:
Thus the annular jet width obtained are as follows:
The beneficial effects of the present invention are:
(1) the circular passage type face obtained according to complete CCW theoretical calculation can make three sections of the shock wave being axially moved point
Turn back, the end in face of turning back at every section, Shock-Shock structure can be eliminated, and then eliminate flow separation and it is leading swash
What is occurred after wave suppresses force gradient, and makes at shock wave one turning angle of every arrival, the Mach that intensity and length constantly increase
It is dry all just downstream to be moved as incident shock continuation.Finally, the incident shock wave surface obtained at annular channel outlet
Smooth, intensity is remarkably reinforced compared with the original incident shock wave generated after rupture of membranes, even flow field after wave, and flow losses are small.
(2) it is compared by numerical simulation, according to the circular passage of CCW theoretical optimization, the shock strength in exit is than initial
Incident shock enhancing 68.1%.Compared with 90 ° of the prominent type annular channel of directly turning back, the shock wave focus moment is advanced by 8 μ s, recessed
76.5% and 32.1% has been respectively increased in surge pressure of the face bottom of chamber portion caused by shock wave focus and peak temperature.
Detailed description of the invention
Fig. 1 is that the present invention is based on the circular passage quasi spline schematic diagrams of complete CCW theory；
Fig. 2 a be incident shock reach first segment turn back face end when, flow field pressure (on), temperature (under) cloud atlas；Fig. 2 b
Be incident shock reach first segment turn back face end when, numerical value schlieren figure (right side)；
Fig. 3 is 90 ° of turn back face and influence comparison diagrams the present invention is based on the circular passage of CCW theory to shock wave focus effect
(Fig. 3 a is the pressure timing comparison diagram of concave surface bottom of chamber portion apex, and Fig. 3 b is the temperature sequence comparison of concave surface bottom of chamber portion apex
Figure)；
Fig. 4 is that the computation model for inhibiting detonation wave revolving structure is constructed the present invention is based on gradually type annular channel；
Fig. 5 a be the anti-knock intracavitary portion in revolving structure concave surface in circular passage of the present invention pressure (on) and temperature (under) cloud atlas
(μ s of t=300.505)；Fig. 5 b be the anti-knock revolving structure concave surface chamber internal numeric schlieren in circular passage of the present invention and 95% OH it is dense
It spends isopleth (μ s of t=300.505)；
Fig. 6 a is the anti-knock revolving structure in circular passage of the present invention, and pinking sharp side has been approached the pressure cloud atlas of concave surface chamber outlet
(on) and temperature cloud picture (under) (μ s of t=313.891)；Fig. 6 b is the anti-knock revolving structure in circular passage of the present invention, and pinking sharp side is
Close to concave surface chamber export numerical value schlieren and 95% OH concentration isopleth (μ s of t=313.891)；
Fig. 7 a is the anti-knock revolving structure in circular passage of the present invention, and detonation wave reaches pressure cloud when concave surface chamber near exit
Figure (on) and temperature cloud picture (under) (μ s of t=314.398)；Fig. 7 b is the anti-knock revolving structure in circular passage of the present invention, and detonation wave arrives
Numerical value schlieren when up to concave surface chamber near exit and 95% OH concentration isopleth (μ s of t=314.398)；
Fig. 8 a is the anti-knock revolving structure in circular passage of the present invention, and detonation wave passes through the outlet of concave surface chamber and circular passage entrance
When the sudden expansion structure of composition pressure cloud atlas (on) and temperature cloud picture (under) (μ s of t=320.371)；Fig. 8 b is that annular of the invention is logical
The anti-knock revolving structure in road, numerical value schlieren when detonation wave is by the outlet of concave surface chamber and the sudden expansion structure of circular passage entrance composition
And 95% OH concentration isopleth (μ s of t=320.371)；
Fig. 9 (a-1) is the μ of t=320.371 s moment, the change curve of flow field temperature No. 1 reference line along Fig. 8 a；Fig. 9
It (a-2) is the μ of t=320.371 s moment, the change curve of flow field temperature No. 2 reference lines along Fig. 8 a；Fig. 9 (a-3) be t=
320.371 μ s moment, the change curve of flow field temperature No. 3 reference lines along Fig. 8 a；When Fig. 9 (a-4) is the μ s of t=320.371
It carves, the change curve of flow field temperature No. 4 reference lines along Fig. 8 a；Fig. 9 (a-5) is the μ of t=320.371 s moment, flow field temperature edge
The change curve of No. 5 reference lines in Fig. 8 a；
Fig. 9 (b-1) is the μ of t=320.371 s moment, the change curve of pressure No. 1 reference line along Fig. 8 a；Fig. 9 (b-2)
For the μ s moment of t=320.371, the change curve of pressure No. 2 reference lines along Fig. 8 a；When Fig. 9 (b-3) is the μ s of t=320.371
It carves, the change curve of pressure No. 3 reference lines along Fig. 8 a；Fig. 9 (b-4) is the μ of the t=320.371 s moment, and pressure is 4 along Fig. 8 a
The change curve of number reference line；Fig. 9 (b-5) is the μ of the t=320.371 s moment, and the variation of pressure No. 5 reference lines along Fig. 8 a is bent
Line chart；
Fig. 9 (c-1) is the μ of t=320.371 s moment, the change curve of density No. 1 reference line along Fig. 8 a；Fig. 9 (c-2)
For the μ s moment of t=320.371, the change curve of density No. 2 reference lines along Fig. 8 a；When Fig. 9 (c-3) is the μ s of t=320.371
It carves, the change curve of density No. 3 reference lines along Fig. 8 a；Fig. 9 (c-4) is the μ of the t=320.371 s moment, and density is 4 along Fig. 8 a
The change curve of number reference line；Fig. 9 (c-5) is the μ of the t=320.371 s moment, and the variation of density No. 5 reference lines along Fig. 8 a is bent
Line chart；
Fig. 9 (d-1) is the μ of the t=320.371 s moment, with H2No. 1 reference along Fig. 8 a of the chemical reaction course variable of O characterization
The change curve of line；Fig. 9 (d-2) is the μ of the t=320.371 s moment, with H2The chemical reaction course variable of O characterization is 2 along Fig. 8 a
The change curve of number reference line；Fig. 9 (d-3) is the μ of the t=320.371 s moment, with H2The chemical reaction course variable edge of O characterization
The change curve of No. 3 reference lines in Fig. 8 a；Fig. 9 (d-4) is the μ of the t=320.371 s moment, with H2The chemical reaction course of O characterization
The change curve of variable No. 4 reference lines along Fig. 8 a；Fig. 9 (d-5) is the μ of the t=320.371 s moment, with H2The chemistry of O characterization is anti-
Answer the change curve of process variable No. 5 reference lines along Fig. 8 a；
Figure 10 a is the anti-knock revolving structure in circular passage of the present invention, when the μ s of t=324.359, pressure cloud atlas (on) and temperature
Cloud atlas (under)；Figure 10 b is the anti-knock revolving structure in circular passage of the present invention, when the μ s of t=324.359, numerical value schlieren and 95% OH
Concentration isogram；
Figure 11 a is the anti-knock revolving structure in circular passage of the present invention, when t=451.243 μ s, pressure cloud atlas (on) and temperature
Cloud atlas (under)；Figure 11 b is the anti-knock revolving structure in circular passage of the present invention, when t=451.243 μ s, numerical value schlieren and 30%
OH concentration isogram；
Figure 12 is different location monitoring point P6, P8, P10, P11, P12, P13 in the anti-knock revolution knot in circular passage of the present invention
Location map in structure；
Figure 13 (1) is the temperature versus time curve figure of the monitoring point P6 in Figure 12；Figure 13 (2) is that P8 is monitored in Figure 12
The temperature versus time curve figure of point；Figure 13 (3) is the temperature versus time curve figure of the monitoring point P10 in Figure 12；
Figure 13 (4) is the temperature versus time curve figure of the monitoring point P11 in Figure 12；Figure 13 (5) is the temperature of the monitoring point P12 in Figure 12
Spend versus time curve figure；Figure 13 (6) is the temperature versus time curve figure of the monitoring point P13 in Figure 12；
Figure 14 (1) is the pressure versus time curve figure of the monitoring point P6 in Figure 12；Figure 14 (2) is that P8 is monitored in Figure 12
The pressure versus time curve figure of point；Figure 14 (3) is the pressure versus time curve figure of the monitoring point P10 in Figure 12；
Figure 14 (4) is the pressure versus time curve figure of the monitoring point P11 in Figure 12；Figure 14 (5) is the pressure of the monitoring point P12 in Figure 12
Power versus time curve figure；Figure 14 (6) is the pressure versus time curve figure of the monitoring point P13 in Figure 12；
Figure 15 (1) be in Figure 12 the monitoring point P6 with H2The chemical reaction course variable versus time curve figure of O characterization；
Figure 15 (2) be in Figure 12 the monitoring point P8 with H2The chemical reaction course variable versus time curve figure of O characterization；Figure 15 (3)
Be in Figure 12 the monitoring point P10 with H2The chemical reaction course variable versus time curve figure of O characterization；Figure 15 (4) is Figure 12
The middle monitoring point P11 is with H2The chemical reaction course variable versus time curve figure of O characterization；
Figure 16 is the pressure and temperature versus time curve figure of the monitoring point P15 in Figure 12；
Figure 17 is the chemical reaction course versus time curve figure of the monitoring point P15 in Figure 12.
Specific embodiment
The present invention is described in detail with reference to the accompanying drawing:
CCW theory, which is Chester, Chisnell and Whitham, passed through three kinds of differences respectively at 1953,1957 and 1958 years
The obtained Shock-Motion Mach number M of method with cross sectional area A variation relation, i.e.,
Wherein,
DM is Mach number infinitesimal；
DA is area element；
K (M) is the function about independent variable Mach number M:
γ is adiabatic exponent；
Parameter μ is also the function about independent variable Mach number M,
According to the work characteristics of 2-stage PDE, the design of anti-knock passback mechanism has a following requirement: first, when fair current
Flow losses are small, and flow losses are big when adverse current；Second, detonation wave passback distance is as short as possible, to put out as early as possible quick-fried；Third, when anti-
After answering area and leading shock wave to decouple, leading shock-wave attenuation is fast, and the pressure fluctuation caused by level-one precombustion chamber wants small.
The present invention provides a kind of design method based on the anti-knock backhaul architecture in complete CCW theory circular passage, sets first
The anti-knock backhaul architecture of the anti-knock backhaul architecture of convex array and end of tape gradual shrinkage circular passage is counted.And base hereafter,
New anti-knock backhaul architecture is devised in the circular passage that complete CCW Theoretical Design gradually makes the transition and on this basis.Most
Afterwards, using H2/O2/N29 component, 48 step reaction mechanism, block structure adaptive mesh refinement and MUSCL-Roe/HLL hybrid algorithm
And semi-implicit Runge-Kutta algorithm has solved the multicomponent Eulerian equation with chemical reaction, analyzes detonation wave and is passing through suppression
Propagation law and flow field evolution Feature when backhaul architecture processed compared the superiority and inferiority of three kinds of anti-knock backhaul architectures of form, disclose
Inhibit the mechanism of detonation wave passback.
The design method of the anti-knock backhaul architecture of the present invention, the specific steps are as follows:
As shown in Figure 1, being one section of straight channel MAM'A' before entering the channel ABCNA'B'C'N' that continuously turns back.This
When, incident shock I0It is propagated to the right along axial direction from left to right.
Step 1, when encounter first segment turn back face AB after, incident shock is reflected in wall surface, reflection type depend on into
Penetrate shock mach number and starting wedge surface angle θw.According to document, in the range of incident Mach 2 ship 1~2, as long as θw23.7 ° of < is just
It is not in regular reflection.Therefore, it in the case where first segment is turned back in face and incident shock intensity is little, preferably uses smaller
θw, to guarantee that incident shock is reflected into Mach reflection on the face of turning back.For M0=1.6 incident shock, takes θ1=25 °,
It is available:
Wherein, M is taken0And Mw0Respectively original incident shock mach number and first segment is turned back the Mach number that Mach is dry in face,
θ1It turns back the starting wedge surface angle in face for first segment.Using genetic algorithm with the precision search of 8.5e-6 in root interval [1,3]
Obtain unique solution Mw0=1.913, substituted into following formula:
Obtain χ1=9.4357 °, wherein χ1It turns back the angle of three wave point tracks and wedge surface in face for first segment.Incident shock
By first segment turn back face during, three wave points will be moved to the face AB at the track at 9.4357 ° of angles along dotted line AA'
A' point.In the process, Mach does Mw0Constantly increase, has arrived A' point, risen to circular passage A'B sections of height.Hereafter, horse
He Gan Mw0It will be as next section A'B' sections of incident shock I1Continuation downstream promotes, and intensity is compared with I0Compared to significantly improving.It is excellent
In the height MM'=200mm of flat segments, therefore, AA' sections of horizontal distance are as follows:
Step 2, as incident shock I1Second segment is encountered to turn back face BC, incident shock I1It is reflected in wall surface, incident shock
I1Mach number Mw0It is 1.913, second segment is turned back the starting wedge surface angle θ in face235 ° are taken as, according to the following formula
Wherein, Mw2Turn back the Mach number that Mach is dry in face for second segment, using genetic algorithm in root interval [ 1,3 ] with
The precision search of 8.5e-6 obtains unique solution Mw2=2.31；
By Mw2=2.31 substitute into following formula:
Obtain χ2=10.382 °, wherein χ2It turns back the angle of three wave point tracks and wedge surface in face for second segment；It is namely incident
Shock wave I1By second segment turn back face during, three wave points will be along dotted line BB', with the face BC at the track at 10.382 ° of angles
Move to B' point；In the process, Mach does Mw2Constantly increase, has arrived B' point, risen to circular passage B'C sections of height；
Mach does Mw2It will be as next section B'C' sections of incident shock I2Continuation downstream promotes, and intensity is compared with I1Compared to bright
It is aobvious to improve；BB' sections along I1Length in incident direction is
In order to allow incident shock I1Stablize a distance, A'B sections along I1Incident direction on take 30mm；Likewise, in order to allow
Mw2Stablize and propagate a distance, takes B'C along I3Length on the direction of propagation is 30mm；
Step 3, as incident shock I2Third section is encountered to turn back face CN, incident shock I2It is reflected in wall surface, incident shock
I2Mach number Mw2It is 2.31, third section is turned back the starting wedge surface angle θ in face330 ° are taken as, according to the following formula
Wherein, Mw3Turn back the Mach number that Mach is dry in face for third section, using genetic algorithm in root interval [ 1,3 ] with
The precision search of 8.5e-6 obtains unique solution Mw3=2.81；
By Mw3=2.81 substitute into following formula:
Obtain χ3=11.7737 °, wherein χ3It turns back the angle of three wave point tracks and wedge surface in face for third section；Namely enter
Penetrate shock wave I2By third section turn back face during, three wave points will be along dotted line CC', with the face CN at the rail at 11.7737 ° of angles
Mark moves to N' point；In the process, Mach does Mw3Constantly increase, has arrived N' point；
CC' sections along I3Length in incident direction is
Thus the annular jet width obtained is
As shown in Fig. 2, the first segment face of turning back according to CCW Theoretical Design can make incident shock turn back 25 ° without generation office
The excessively high temperature and pressure in portion.High temperature, higher-pressure region concentrate on after reflected shock wave, maximum pressure 0.39MPa, and maximum temperature is
482K.On the one hand fuel premature ignition before the chamber of concave surface is avoided, while also ensures the uniformity in flow field.
Fig. 3 a, Fig. 3 b are the computation model (the present invention is based on the circular passages of CCW theory) of new experimental provision, old reality respectively
The pressure and temperature timing comparison diagram of computation model (90 ° of faces of turning back) concave surface bottom of chamber portion apex of experiment device.As can be seen that this
Based in the gradually computation model in type annular channel, the shock wave focus moment is advanced by 8 μ s, surge pressure 3.49MPa for invention, than
The 1.96MPa of old computation model improves 76.5%；Peak temperature is 1155K, and the 874K than old computation model improves 32.1%.
Below to the present invention is based on the anti-knock backhaul architectures in gradually type annular channel to carry out numerical simulation analysis:
Suppression of the present invention is constructed based on gradually type annular channel (d=4.228mm) and concave surface chamber outlet diameter, D=50mm
Detonation wave backhaul architecture processed, establishes computation model as shown in Figure 4.
After shock wave focuses in concave surface bottom of chamber portion, the high hot spot of energy density is formd, almost having detonated immediately, it is quick-fried to drive
Shake.Then, the concave surface chamber that pinking wave direction sectional area increases rapidly, which exports, to be propagated, and C-J pinking is gradually decayed to.Fig. 5 a is concave surface chamber
Internal temperature and pressure cloud atlas.It can be seen that the leading shock wave sharp side of top half and the reaction zone sharp side of lower half portion
It is close-coupled.Fig. 5 b gives the OH concentration isopleth of corresponding density gradient cloud atlas and 95%, it is seen then that dense with 95% OH
Degree isopleth is the reaction zone sharp side of mark and leading shock wave sharp side is close-coupled.
In Fig. 6, pinking sharp side has been approached the outlet of concave surface chamber.In concave surface, chamber cross-sectional area is increased rapidly and annular jet
Under the double action of outlet inside vortex, detonation wave becomes more unstable.The pinking cutting edge of a knife or a sword of high-visible fold from Fig. 6 b
Face, and it is divided into the 95%OH concentration isopleth of several discontinuous segmental arcs, these phenomenons are all the enhancings of detonation wave unstability
Performance.The reflected shock wave that detonation wave generates on the cavity wall face of concave surface generates weak compressional wave in the reaction zone on pinking sharp side, this
The heat that a little compressional waves are constantly discharged in the reaction zone of pinking sharp side is reinforced, and crossed shock is finally superposed to.Temperature from Fig. 6 a
If degree and pressure cloud atlas are as it can be seen that tow the longer dark trace in arterial highway, these are crossed shocks after pinking sharp side.
When detonation wave reaches concave surface chamber near exit, interact with the vortex at annular channel outlet.Due to whirlpool
Stream area is low temperature, low-pressure area (Fig. 7 a), therefore reaction sharp side herein lags behind leading shock wave, and detonation wave starts to decouple, such as Fig. 7 b
It is shown.
As shown in Figure 1, circular passage is a size relatively untethered region bigger relative to concave surface chamber outlet diameter.
Therefore, chamber outlet in concave surface constitutes a sudden expansion structure with circular passage entrance, and detonation wave will pass through this by the part of near wall
A turning is to annular jet upstream diffraction.
The diverging of the flow tube as caused by the effect and section sudden expansion of corner's dilatational wave, finally determines detonation wave in concave surface
Chamber outlet is diffracted to subcritical diffraction, and detonation wave gradually decouples, as shown in figs. 8 a and 8b.
Fig. 9 (a-1)~Fig. 9 (d-5) gives the μ s moment of t=320.371, flow field temperature, pressure, density and reaction process
Variable is along 1~5(of reference line Fig. 8 a) change curve.Peak value along each thermodynamic parameter of 1# reference line is still the largest.Note
It anticipates and arrives, along 4# and 5# reference line, a biggish bust can all occur in temperature, pressure and density, this is because passing through vortex
Caused by area.Near corresponding position, with H2The chemical reaction course variable of O characterization is also reduced to 0, this shows attached in vortex
Close detonation wave extinguishes completely, and chemical reaction terminates.Then, there is a jumping again in these thermodynamic parameters, in density and
It is particularly evident in pressue-graph, this is because having passed through caused by the secondary shock high temperature relevant with detonation wave, high-pressure area.It is logical
Chemical reaction course variable curve is crossed it is found that chemical reaction in this area is acutely and complete.
At the μ s moment of t=324.359, by Figure 10 b, as it can be seen that 95%OH isopleth is only left, several sections of very short segmental arcs are fragmentary to be dissipated
Cloth is on pinking sharp side, and by Figure 10 a as it can be seen that pressure and temperature also declines much after wave, detonation wave is obviously decayed.From schlieren figure
In, it is clear that the detonation wave to the anti-pass of annular jet upstream is full decoupled, leading shock wave and reaction zone sharp side
It is kept completely separate.And at this point, reaction zone has not caught up with the movement of leading shock wave yet near symmetry axis, pinking sharp side starts to solve
Coupling.
Since the sectional area of circular passage is diverging along updrift side, shock wave can decay rapidly, the leading shock wave of decoupling
With flame front after entering circular passage will not secondary coupling again, as shown in Figure 11 a and Figure 11 b.From the 30%OH etc. in Figure 11 b
It is worth line as it can be seen that reaction zone and leading shock wave are full decoupled.
Figure 13 (1)~Figure 13 (6) is that different location monitoring point P6, P8, P10, P11, P12, P13(specific location is shown in Figure 12)
Temperature versus time curve.Notice two monitoring points P12 and P13, their peak temperature illustrates quick-fried less than 750K
Seismic wave has put out quick-fried when reaching herein.
Figure 14 (1)~Figure 14 (6) is that pressure changes with time at monitoring point P6, P8, P10, P11, P12, P13 in Figure 12
Curve, visible pressure substantially rises to twice in figure, for the first time for caused by incident shock, second is caused by passback wave.Lower-left
The enlarged drawing at angle is passback wave region, it is found that the surge pressure at the P13 of annular jet outlet upstream is
Very little, about 0.25MPa.
Figure 15 (1)~Figure 15 (4) be in Figure 12 at monitoring point P6, P8, P10, P11 with H2The chemical reaction course of O characterization
Variable versus time curve.Obviously, chemical reaction course variable is always 0 at monitoring point P12 and monitoring point P13.It is logical
Cross analysis shows, chemical reaction terminated between P11 and P12, i.e., flame is in annular jet outlet upstream 0mm
Extinguish to the somewhere of 8mm.
Figure 16 is the pressure and temperature versus time curve of monitoring point P15 in Figure 12.P15 is located at first segment and turns back face
Inlet upstream, the horizontal distance away from annular jet outlet center are 46mm, vertical range 56mm.Obviously, before passback
It leads shock wave to reach at P15 in the μ s moment of t=319.7, surge pressure at this time has decayed to 0.13MPa, is fire point peak value pressure
The 0.9% of power 13.59MPa, peak temperature are no more than 550K.Meanwhile the chemical reaction course from monitoring point P15 in Figure 17 becomes
Amount versus time curve can be seen that respectively with H2The chemical reaction course variable of O and OH characterization is always 0.This shows
Away from annular jet outlet central horizontal distance 46mm, vertical range is to return at 56mm without flame.
It is anti-much smaller than what the concave surface chamber (D=50mm) of critical pipe diameter designed using outlet diameter based on gradually type annular channel
Pinking backhaul architecture effectively can inhibit detonation wave to return.
(1) in numerical simulation, it is located at upstream, away from annular jet outlet central point horizontal distance 46mm, vertical range
At 56mm monitoring point statistics indicate that without flame return, return shock wave after surge pressure decayed to 0.13MPa, be fire point
The 0.9% of surge pressure 13.59MPa, peak temperature is no more than 550K, with OH and H2The chemical reaction course variable of O characterization is always
It is 0, shows no flame passback.
(2) mechanism of action that this anti-knock backhaul architecture can effectively inhibit detonation wave to return can be summarized as following four
Point: first, concave surface chamber outlet diameter is much smaller than critical pipe diameter；Second, annular jet exit, the vortex temperature of jet stream induction
It is lower with pressure, cause chemical reaction rate to reduce, or even terminate reaction；Third；Gradually type annular based on CCW Theoretical Design
Channel can detonate pinking under conditions of driving pressure is very low, and therefore, the over-drive value of detonation wave is lower, in diffraction process
It is easy to put out quick-fried；4th, since circular passage is diverging along the sectional area of updrift side, the pinking sharp side of decoupling is in circular passage
In propagation be equivalent to the cylinder pinking of a diverging, leading shock wave decays rapidly, and chemical reaction rate declines rapidly, therefore decouples
Pinking sharp side decay always without coupling again.
Claims (1)
1. the design method based on the anti-knock backhaul architecture in complete CCW theory circular passage, it is characterised in that: including following step
It is rapid:
Step 1,
1.1 incident shock I firstoIt is axial to propagate to the right, when encounter first segment turn back face AB after, incident shock IoOccur in wall surface
Reflection, incident shock IoMach number MoIt is 1.6, first segment is turned back the starting wedge surface angle θ in face125 ° are taken as, according to the following formula
Wherein, Mw0It turns back the Mach number that Mach is dry in face for first segment；
Unique solution M is obtained with the precision search of 8.5e-6 in root interval [1,3] using genetic algorithmw0=1.913；
1.2 by Mw0=1.913 substitute into following formula:
Obtain χ1=9.4357 °, wherein χ1It turns back the angle of three wave point tracks and wedge surface in face for first segment；It is namely incident to swash
Wave by first segment turn back face during, three wave points will be along dotted line AA', to transport with the face AB at the track at 9.4357 ° of angles
It moves to A' point；In the process, Mach does Mw0Constantly increase, has arrived A' point, risen to circular passage A'B sections of height；
1.3 Mach of dry Mw0It will be as next section A'B' sections of incident shock I1Continuation downstream promotes, and intensity is compared with IoCompared to obvious
It improves；Better than the height MM'=200mm of flat segments, therefore, AA' sections of horizontal distance are as follows:
Step 2,
2.1 work as incident shock I1Second segment is encountered to turn back face BC, incident shock I1It is reflected in wall surface, incident shock I1Mach
Number Mw0It is 1.913, second segment is turned back the starting wedge surface angle θ in face235 ° are taken as, according to the following formula
Wherein, Mw2Turn back the Mach number that Mach is dry in face for second segment, using genetic algorithm in root interval [1,3] with
The precision search of 8.5e-6 obtains unique solution Mw2=2.31；
2.2 by Mw2=2.31 substitute into following formula:
Obtain χ2=10.382 °, wherein χ2It turns back the angle of three wave point tracks and wedge surface in face for second segment；It is namely incident to swash
Wave I1By second segment turn back face during, three wave points will be along dotted line BB', with the track with the face BC at 10.382 ° of angles
Move to B' point；In the process, Mach does Mw2Constantly increase, has arrived B' point, risen to circular passage B'C sections of height；
2.3 Mach of dry Mw2It will be as next section B'C' sections of incident shock I2Continuation downstream promotes, and intensity is compared with I1Compared to obvious
It improves；BB' sections along I1Length in incident direction are as follows:
In order to allow incident shock I1Stablize a distance, A'B sections along I1Incident direction on take 30mm；Likewise, in order to allow Mw2Surely
Surely a distance is propagated, takes B'C along I3Length on the direction of propagation is 30mm；
Step 3,
3.1 work as incident shock I2Third section is encountered to turn back face CN, incident shock I2It is reflected in wall surface, incident shock I2Mach
Number Mw2It is 2.31, third section is turned back the starting wedge surface angle θ in face330 ° are taken as, according to the following formula
Wherein, Mw3Turn back the Mach number that Mach is dry in face for third section, using genetic algorithm in root interval [1,3] with
The precision search of 8.5e-6 obtains unique solution Mw3=2.81；
3.2 by Mw3=2.81 substitute into following formula:
Obtain χ3=11.7737 °, wherein χ3It turns back the angle of three wave point tracks and wedge surface in face for third section；It is namely incident to swash
Wave I2By third section turn back face during, three wave points will be along dotted line CC', with the track with the face CN at 11.7737 ° of angles
Move to N' point；In the process, Mach does Mw3Constantly increase, has arrived N' point；
3.3CC' sections along I3Length in incident direction are as follows:
Thus the annular jet width obtained are as follows:
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