Liquid-liquid coaxial centrifugal nozzle combustion instability active control injection panel

Abstract

The application discloses a liquid-liquid coaxial centrifugal nozzle combustion instability active control injection panel, which comprises an upper cover plate, an internal centrifugal nozzle, an external centrifugal nozzle and a pressure measuring device; the upper cover plate comprises a cylindrical cavity A, a cylindrical cavity B and a propellant supply flow channel; the external centrifugal nozzle comprises an outer rotational flow chamber, an outer straight section and a jet base plate; the jet base plate is detachably connected with a combustion chamber in a sealing mode; a plurality of secondary propellant injection holes are uniformly arranged on the jet base plate in a circumferential direction; each secondary propellant injection hole is connected with a secondary propellant collecting cavity and the combustion chamber; the internal centrifugal nozzle comprises an inner rotational flow chamber and an inner straight section coaxially arranged at the bottom of the inner rotational flow chamber. When the liquid-liquid coaxial centrifugal nozzle is in combustion instability, the pressure oscillation amplitude in the combustion chamber is monitored, then the flow of secondary fuel injection is actively and dynamically adjusted, the pressure oscillation amplitude in the combustion chamber is continuously observed, and the active control effect is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of liquid rocket engine spray combustion, in particular to a liquid-liquid coaxial centrifugal nozzle combustion instability active control injection panel. BACKGROUND

[0002] Liquid-liquid coaxial centrifugal nozzle is widely used in domestic and foreign bipropellant liquid rocket engines due to its excellent high specific impulse performance. The liquid-liquid coaxial centrifugal nozzle can be regarded as the combination of two centrifugal nozzles. The propellants enter the nozzle from the inner and outer tangential holes to form rotating flows. The two rotating coaxial hollow annular liquid films converge near the outlet, and the mutual mixing intensifies the liquid film breakup to form a spray field, which is then combusted in the combustion chamber.

[0003] The atomization and mixing process of the liquid-liquid coaxial centrifugal nozzle is a complex physical process involving the formation of rotating vortex, the collision and convergence of double-layer rotating liquid film, the aggregation and breakup of liquid droplets, etc. The atomization effect greatly affects the evaporation, mixing and combustion of fuel in the combustion chamber, and has an important influence on combustion instability of the engine. SUMMARY

[0004] The technical problem solved by the present application is to provide a liquid-liquid coaxial centrifugal nozzle combustion instability active control injection panel to solve the problems of the prior art. The liquid-liquid coaxial centrifugal nozzle combustion instability active control injection panel can actively and dynamically adjust the flow rate of secondary fuel injection when combustion instability occurs in the liquid-liquid coaxial centrifugal nozzle by monitoring the pressure oscillation amplitude in the combustion chamber, and continuously observing the pressure oscillation amplitude in the combustion chamber to achieve active control effect.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] A liquid-liquid coaxial centrifugal nozzle combustion instability active control injection panel, comprising an upper cover plate, an inner centrifugal nozzle and an outer centrifugal nozzle.

[0007] The upper cover plate comprises a cylindrical cavity A, a cylindrical cavity B and a propellant supply flow channel.

[0008] The cylindrical cavity A and the cylindrical cavity B are coaxially arranged from top to bottom.

[0009] The propellant supply flow channel comprises a propellant A supply flow channel, a propellant B supply flow channel and a secondary propellant supply flow channel.

[0010] The outer centrifugal nozzle comprises an outer rotating flow chamber, an outer straight section and a jet bottom plate.

[0011] The outer straight section is coaxially and integrally arranged at the bottom of the outer rotating flow chamber, and the bottom is in communication with the combustion chamber.

[0012] The top outer wall of the outer swirled chamber is sealingly connected with the bottom inner wall of the cylindrical cavity A, and the bottom outer wall of the outer swirled chamber is sealingly connected with the middle part of the cylindrical cavity B, so that the cylindrical cavity A at the top of the outer swirled chamber forms a sealed propellant A collecting cavity, the cylindrical cavity B at the outer periphery of the outer swirled chamber forms a sealed propellant B collecting cavity, and the outer swirled chamber is connected with the propellant B liquid supply channel through the outer tangential hole.

[0013] The propellant A liquid supply channel is used for conveying liquid propellant A to the propellant A collecting cavity.

[0014] The propellant B liquid supply channel is used for conveying liquid propellant B to the propellant B collecting cavity.

[0015] The secondary propellant supply channel is used for conveying liquid or gas propellant A and / or propellant B to the secondary propellant collecting cavity.

[0016] The injection base plate is sealingly and detachably connected with the combustion chamber, and a plurality of secondary propellant injection holes are uniformly arranged on the injection base plate at the outer periphery of the outer straight section in the circumferential direction, each of the secondary propellant injection holes being connected with the secondary propellant collecting cavity and the combustion chamber.

[0017] The inner centrifugal nozzle is coaxially and detachably inserted into the outer centrifugal nozzle, and the inner centrifugal nozzle comprises an inner swirled chamber and an inner straight section coaxially arranged at the bottom of the inner swirled chamber.

[0018] The top of the inner swirled chamber is connected with the propellant A collecting cavity through the inner tangential hole.

[0019] The combustion chamber is provided with a pressure measuring device and a photomultiplier tube.

[0020] The pressure measuring device comprises a static pressure sensor and three high-frequency dynamic pressure sensors.

[0021] The static pressure sensor can be used for monitoring the static pressure in the combustion chamber.

[0022] The three high-frequency dynamic pressure sensors are arranged along the longitudinal direction of the combustion chamber and are respectively used for monitoring the head high-frequency pressure, the middle high-frequency pressure and the tail high-frequency pressure of the combustion chamber at each time.

[0023] The photomultiplier tube collects the CH * flame light intensity at each time in the combustion chamber, and further collects the heat release pulsation in the combustion chamber.

[0024] Through the cooperation of the pressure measuring device and the photomultiplier tube, whether longitudinal combustion instability occurs in the combustion chamber can be monitored.

[0025] The judgment method of longitudinal combustion instability in the combustion chamber is:

[0026] Step 1, judging combustion instability: when the head high frequency pressure, the middle high frequency pressure and the tail high frequency pressure are all periodically changed, record the oscillation period, the oscillation frequency and the oscillation amplitude T1 of the head high frequency pressure; then, calculate the ratio K of the oscillation amplitude T1 and the combustion chamber static pressure P1; when K≥5%, it is considered that the combustion instability occurs in the combustion chamber.

[0027] Step 2, preliminary judging longitudinal combustion instability: according to the head high frequency pressure, the middle high frequency pressure and the tail high frequency pressure at different time, draw the longitudinal pressure time phase curve of the combustion chamber, and preliminarily judge whether the combustion instability occurs longitudinally in the combustion chamber.

[0028] Step 3, secondary judging longitudinal combustion instability: when it is preliminarily judged in step 2 that the combustion instability occurs longitudinally in the combustion chamber, compare the phase difference Δ of the oscillation phase of the high frequency pressure and the phase of the heat release pulse, and when Δ<90°, it is determined that the longitudinal combustion instability occurs in the combustion chamber.

[0029] When the longitudinal combustion instability occurs in the combustion chamber, according to the ratio K at the current time, the secondary propellant injection flow rate of each secondary propellant injection hole is actively and dynamically adjusted until the stable combustion of the combustion chamber is realized.

[0030] The active and dynamic adjustment method of the secondary propellant injection flow rate in each secondary propellant injection hole comprises the following steps:

[0031] Step 4-1, setting K value levels: the K value is set to 6 levels in order from small to large.

[0032] Step 4-2, setting flow amplitude L levels: the secondary propellant injection flow rate is a sinusoidal pulse jet flow with a flow amplitude L; the flow amplitude L is set to 6 levels in order from small to large.

[0033] Step 4-3, drawing K-L correspondence table: the 6 levels of K value in step 4-1 and the 6 levels of flow amplitude L in step 4-2 are one-to-one corresponding, and the K-L correspondence table is drawn.

[0034] Step 4-4, selecting flow amplitude L: according to the ratio K calculated in step 1, the corresponding flow amplitude L is selected from the K-L correspondence table in step 4-3.

[0035] Step 4-5, determining the secondary propellant injection flow rate: each secondary propellant injection hole carries out the sinusoidal pulse jet flow of the secondary propellant with the oscillation frequency of the head high frequency pressure in step 1 as the pulse frequency and the flow amplitude L selected in step 4-4 as the pulse amplitude.

[0036] In step 4-1, the 6 levels of K value are 0%-5%, 5%-10%, 10%-20%, 20%-30%, 30%-40% and 50% respectively; in step 4-2, the 6 levels of flow amplitude L value are 0%F, 2%F, 4%F, 6%F, 8%F and 10%F respectively; wherein, when the secondary propellant is propellant A, F is the total flow of propellant A in the propellant A supply channel; when the secondary propellant is propellant B, F is the total flow of propellant B in the propellant B supply channel.

[0037] Step 4-6, finding the optimal flow amplitude L, specifically comprising the following steps.

[0038] Step 4-6a, calculating the ratio K': after setting the secondary propellant injection flow determined in step 4-5 for a certain period of time, extracting the oscillation amplitude T2 of the head high-frequency pressure at this time and the combustion chamber static pressure P2 at this time, and calculating the ratio K' = T2 / P2.

[0039] Step 4-6b, judging the combustion stability: when the ratio K' is less than the set expected ratio, it is considered that the combustion instability is suppressed.

[0040] Step 4-6c, reducing the flow amplitude L: assuming that in step 4-1, the 6 levels of ratio K are K1, K2, K3, K4, K5 and K6 in order from small to large; assuming that the ratio K calculated in step 1 is Ki; wherein, 1≤i≤6; after step 4-6b judges that the combustion instability is suppressed, then according to the ratio K calculated in step 1, the flow amplitude L' is selected, specifically:

[0041] A, when i = 1, the flow amplitude L corresponding to K1 in the K-L correspondence table is the optimal flow amplitude L.

[0042] B, when 2≤i≤6, the flow amplitude L corresponding to Ki-1 in the K-L correspondence table in step 4-3 is selected as the selected flow amplitude L'.

[0043] Step 4-6d, repeating steps 4-6a to 4-6c, under the premise that the combustion instability is suppressed, the selected minimum flow amplitude L' is taken as the optimal flow amplitude L; then, each secondary propellant injection hole performs sinusoidal pulsed jet of secondary propellant with the oscillation frequency of the head high-frequency pressure in step 1 as the pulse frequency and the optimal flow amplitude L' selected in step 4-6c or step 4-6d as the pulse amplitude.

[0044] By changing the position, injection angle, area and outlet Reynolds number of each secondary propellant injection hole respectively, the inhibitory effect of one or more influencing factors on the longitudinal combustion instability of the combustion chamber can be explored.

[0045] When each secondary propellant injection hole stops injecting secondary propellant, the length of the inner centrifugal nozzle is changed, the retracted length between the inner and outer centrifugal nozzles is changed, and the influence of the retracted length on longitudinal combustion instability of the combustion chamber is studied.

[0046] The inner swirled chamber top of the inner centrifugal nozzle and the cylinder cavity A top are connected through the mortise and tenon joint of the boss and the groove, so that the axial positioning of the inner centrifugal nozzle is realized.

[0047] The present application has the following beneficial effects:

[0048] 1. The outer centrifugal nozzle has eight secondary fuel injection holes distributed along the axial direction, the injection hole position, the injection angle, the injection hole area and the liquid nozzle outlet Reynolds number can be changed to explore the inhibition effect of the same on the combustion instability of the coaxial centrifugal nozzle.

[0049] 2. The secondary fuel injection type can be single propellant or mixture of double propellant, and even gas fuel can be used, so that the inhibition effect of the fuel type on the combustion instability of the coaxial centrifugal nozzle can be explored, and the best control scheme can be explored.

[0050] 3. When the secondary fuel is not injected, the present application is a coaxial centrifugal nozzle, so that the influence of the parameter change on the combustion instability can be studied. For example, the length of the inner centrifugal nozzle is changed to change the retracted length between the inner and outer centrifugal nozzles, and the influence of the retracted length on the combustion instability is studied.

[0051] 4. The present application has high modularization degree, compact structure and good stability. All the above research methods can be cross-researched, can provide guidance and suggestions for active control of combustion instability of the coaxial centrifugal nozzle, and has broad research and application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 A three-dimensional view of the injection panel for active control of combustion instability of the coaxial centrifugal nozzle is shown.

[0053] Figure 2 A longitudinal section view of the injection panel for active control of combustion instability of the coaxial centrifugal nozzle is shown.

[0054] Figure 3 A longitudinal section view of the upper cover plate in the present application is shown.

[0055] Figure 4 A longitudinal section view of the inner centrifugal nozzle in the present application is shown.

[0056] Figure 5 A longitudinal section view of the outer centrifugal nozzle in the present application is shown.

[0057] Wherein:

[0058] 1. upper cover plate;

[0059] 11. threaded hole one; 12. propellant B supply flow channel; 13. propellant A supply flow channel; 14. secondary propellant supply flow channel;

[0060] 15. radial sealing groove one; 16. monitoring sensor;

[0061] 2. internal centrifugal nozzle;

[0062] 21. boss; 22. inner tangential hole; 23. axial sealing groove one; 24. inner straight section; 25. inner converging section; 26. inner swirl chamber

[0063] 3. external centrifugal nozzle;

[0064] 31. axial sealing groove two; 32. threaded hole two; 33. radial sealing groove two; 34. secondary propellant injection hole; 35. outer straight section;

[0065] 36. outer converging section; 37. outer swirl chamber; 38. outer tangential hole

[0066] 4. propellant A collection cavity; 5. propellant B collection cavity; 6. secondary propellant collection cavity. DETAILED DESCRIPTION

[0067] The application will be described in further detail below with reference to the drawings and specific preferred embodiments.

[0068] In the description of the application, it should be understood that the terms "left side", "right side", "upper", "lower", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and "first", "second", etc. do not represent the importance of the parts, so it cannot be understood as a limitation on the application. The specific dimensions used in the embodiments are only for the purpose of illustrating the technical solutions and do not limit the protection scope of the application.

[0069] As shown in Figure 1 and Figure 2 A liquid-liquid coaxial centrifugal nozzle combustion unstable active control injection panel, comprising an upper cover plate 1, an internal centrifugal nozzle 2, an external centrifugal nozzle 3 and a monitoring sensor 16.

[0070] As shown in Figure 3 The upper cover plate comprises a cylindrical cavity A, a cylindrical cavity B and a propellant supply flow channel.

[0071] Cylindrical cavity A and cylindrical cavity B are coaxially arranged from top to bottom. In this invention, the diameter of cylindrical cavity A is smaller than the diameter of cylindrical cavity B, that is, cylindrical cavity A is a small cylindrical cavity and cylindrical cavity B is a large cylindrical cavity.

[0072] A top flange is preferably provided on the outer periphery of the small cylindrical cavity, and a lower flange is preferably provided on the outer periphery of the bottom of the large cylindrical cavity. Both the upper and lower flanges preferably have a plurality of threaded holes 11 evenly distributed circumferentially. The threaded holes 11 on the upper flange are used for connection to external devices.

[0073] The propellant supply channels include propellant A supply channel 13, propellant B supply channel 12, and secondary propellant supply channel 14.

[0074] like Figure 5 As shown, the external centrifugal nozzle includes an external swirling chamber 37, an external contraction section 36, an external straight section 35, and a spray base plate.

[0075] The outer straight section is preferably coaxially integrated with the outer contraction section 36 at the bottom of the outer swirl chamber, and the bottom is connected to the combustion chamber.

[0076] The top outer wall of the outer vortex chamber is preferably sealed to the bottom inner wall of the cylindrical cavity A through an axial sealing groove 31, and the bottom outer wall of the outer vortex chamber is preferably sealed to the middle of the cylindrical cavity B through an axial sealing groove 31, so that the cylindrical cavity A located at the top of the outer vortex chamber forms a sealed propellant A collection chamber 4; the cylindrical cavity B located at the outer periphery of the outer vortex chamber forms a sealed propellant B collection chamber 5; the outer vortex chamber is connected to the propellant B supply channel through an outer tangential hole 38; and the cylindrical cavity B located at the outer periphery of the outer isolinear section forms a sealed secondary propellant collection chamber 6.

[0077] The propellant A supply channel is used to deliver liquid propellant A to the propellant A collection chamber.

[0078] The propellant B supply channel is used to deliver liquid propellant B to the propellant B collection chamber.

[0079] The secondary propellant supply channel is used to deliver liquid or gaseous propellant A and / or propellant B to the secondary propellant collection chamber.

[0080] The injection base plate is preferably detachably connected to the combustion chamber via threaded hole 2 32 and radial sealing groove 2 33; at the same time, the injection base plate is also preferably detachably connected to the upper cover plate via threaded hole 2 32 and radial sealing groove 15.

[0081] A plurality of secondary propellant injection holes 34, preferably eight, are evenly arranged circumferentially on the injection base plate located on the outer periphery of the straight section. Each secondary propellant injection hole is connected to the secondary propellant collection chamber and the combustion chamber.

[0082] The inner centrifugal nozzle is coaxially and detachably inserted into the outer centrifugal nozzle.

[0083] As shown in Figure 4 The inner centrifugal nozzle comprises, from top to bottom, an inner swirl chamber 26, an inner convergent section 25 and an inner straight section 24 which are coaxially and integrally arranged.

[0084] The top of the inner swirl chamber is preferably connected with the top end surface of the cylindrical cavity A through the tenon-and-mortise cooperation of the boss 21 and the groove, so as to realize the axial positioning of the inner centrifugal nozzle.

[0085] The top of the inner swirl chamber is preferably connected with the propellant A collecting cavity through the inner tangential hole 22.

[0086] The bottom of the inner swirl chamber is preferably detachably and sealingly connected with the top of the outer centrifugal nozzle through the axial sealing groove 23.

[0087] The pressure measuring device can monitor the pressures in the propellant A collecting cavity, the propellant B collecting cavity and the secondary propellant collecting cavity.

[0088] The above monitoring sensor comprises three pressure sensors and three flow meters.

[0089] The three pressure sensors are respectively used for monitoring the pressures in the propellant A collecting cavity, the propellant B collecting cavity and the secondary propellant collecting cavity.

[0090] The three flow meters are respectively used for monitoring the propellant flow rates at the inlets or outlets of the propellant A collecting cavity, the propellant B collecting cavity and the secondary propellant collecting cavity.

[0091] The combustion chamber is provided with a pressure measuring device and a photomultiplier tube.

[0092] The pressure measuring device comprises a static pressure sensor and three high-frequency dynamic pressure sensors.

[0093] The static pressure sensor can be used for monitoring the static pressure in the combustion chamber.

[0094] The three high-frequency dynamic pressure sensors are arranged along the longitudinal direction of the combustion chamber and are respectively used for monitoring the head high-frequency pressure, the middle high-frequency pressure and the tail high-frequency pressure of the combustion chamber at each time.

[0095] The photomultiplier tube collects the CH * flame luminous intensity at each time in the combustion chamber, and further collects the heat release pulsation in the combustion chamber.

[0096] Through the cooperative cooperation of the pressure measuring device and the photomultiplier tube, whether longitudinal combustion instability occurs in the combustion chamber can be monitored, and the specific judgment method is as follows:

[0097] Step 1, judging combustion instability: when the head high frequency pressure, the middle high frequency pressure and the tail high frequency pressure are periodically changed, the oscillation period, the oscillation frequency and the oscillation amplitude T1 of the head high frequency pressure are recorded; then, the ratio K of the oscillation amplitude T1 and the combustion chamber static pressure P1 is calculated; when K≥5%, it is considered that the combustion instability occurs in the combustion chamber.

[0098] Step 2, initially judging longitudinal combustion instability: according to the head high frequency pressure, the middle high frequency pressure and the tail high frequency pressure at different time, the longitudinal pressure time phase curve of the combustion chamber is drawn, and it is initially judged whether the combustion instability occurs longitudinally in the combustion chamber.

[0099] Step 3, secondly judging longitudinal combustion instability: when it is initially judged that the combustion instability occurs longitudinally in the combustion chamber in step 2, the phase difference Δ of the oscillation phase of the high frequency pressure and the phase of the heat release pulse is compared; when Δ<90°, it is determined that the longitudinal combustion instability occurs in the combustion chamber.

[0100] When the longitudinal combustion instability occurs in the combustion chamber, the secondary propellant injection flow rate of each secondary propellant injection hole is actively and dynamically adjusted according to the ratio K at the current time, until the stable combustion of the combustion chamber is realized.

[0101] The active and dynamic adjustment method of the secondary propellant injection flow rate in each secondary propellant injection hole comprises the following steps.

[0102] Step 4-1, setting K value levels: the K values are set as 6 levels in order from small to large, and the 6 levels of the K values in the embodiment are preferably 0%-5%, 5%-10%, 10%-20%, 20%-30%, 30%-40% and 50% respectively.

[0103] Step 4-2, setting flow amplitude L levels: the secondary propellant injection flow rate is a sinusoidal pulse jet, that is, it can produce a sinusoidal half wave, and thus has a flow amplitude L; in the embodiment, the flow amplitude L is set as 6 value levels, which are 0%F, 2%F, 4%F, 6%F, 8%F and 10%F respectively; wherein, when the secondary propellant is propellant A, F is the total flow rate of propellant A in the propellant A supply flow channel; when the secondary propellant is propellant B, F is the total flow rate of propellant B in the propellant B supply flow channel.

[0104] Step 4-3, drawing K-L correspondence table: the 6 levels of the K values in step 4-1 and the 6 value levels of the flow amplitude L in step 4-2 are corresponded one by one, and the following K-L correspondence table is drawn.

[0105]

[0106] Step 4-4, selecting flow amplitude L: according to the ratio K calculated in step 1, selecting the corresponding flow amplitude L from the K-L corresponding table in step 4-3.

[0107] Step 4-5, determining the secondary propellant injection flow: each secondary propellant injection hole is subjected to sinusoidal pulsed jet of secondary propellant injection with the oscillation frequency of the head high frequency pressure in step 1 as the pulse frequency and the flow amplitude L selected in step 4-4 as the pulse amplitude.

[0108] Step 4-6, finding the optimal flow amplitude L, specifically including the following steps.

[0109] Step 4-6a, calculating the ratio K': after the secondary propellant injection flow determined in step 4-5 is set for a certain period of time, the oscillation amplitude T2 of the head high frequency pressure at this time and the static pressure P2 of the combustion chamber at this time are extracted, and the ratio K' = T2 / P2 is calculated.

[0110] Step 4-6b, judging the combustion stability: when the ratio K' is less than the set expected ratio, it is considered that the combustion instability is suppressed. At this time, the expected ratio is preferably around 5%, and further preferably less than 5%.

[0111] When the ratio K' is not less than the set expected ratio, the combustion instability is suppressed by increasing the flow amplitude L or adjusting the expected ratio.

[0112] Step 4-6c, reducing the flow amplitude L: assuming that in step 4-1, the 6 levels of the ratio K are K1, K2, K3, K4, K5 and K6 in order from small to large; assuming that the ratio K calculated in step 1 is Ki; wherein 1≤i≤6; after the combustion instability is judged to be suppressed in step 4-6b, the flow amplitude L' is selected according to the ratio K calculated in step 1, specifically as follows:

[0113] A, when i = 1, the flow amplitude L corresponding to K1 in the K-L corresponding table is the optimal flow amplitude L.

[0114] B, when 2≤i≤6, the flow amplitude L corresponding to Ki-1 should be selected from the K-L corresponding table in step 4-3 as the selected flow amplitude L'.

[0115] Step 4-6d, repeating step 4-6a to step 4-6c, and taking the selected minimum flow amplitude L' as the optimal flow amplitude L before the combustion instability is suppressed; then, each secondary propellant injection hole is subjected to sinusoidal pulsed jet of secondary propellant with the oscillation frequency of the head high frequency pressure in step 1 as the pulse frequency and the optimal flow amplitude L' selected in step 4-6c or step 4-6d as the pulse amplitude.

[0116] The present application adds secondary fuel injection to the liquid-liquid coaxial centrifugal nozzle to actively control combustion instability and reduce the amplitude of pressure oscillation in the combustion chamber. The principle behind this method is as follows: ① The secondary fuel injection acts on the two rotating liquid films, thereby strengthening the mixing of the liquid films and further breaking them up to form a more uniform spray, improving the atomization effect; ② The secondary fuel injection can change the flow field structure at the head of the combustion chamber, which is conducive to improving combustion stability.

[0117] Therefore, the liquid-liquid coaxial centrifugal nozzle combustion instability active control has broad research and application prospects.

[0118] Further, the present application can explore the inhibitory effect of one or more influencing factors on longitudinal combustion instability in the combustion chamber by changing the position, injection angle, area, and outlet Reynolds number of each secondary propellant injection hole.

[0119] When each secondary propellant injection hole stops injecting secondary propellant, the length of the inner centrifugal nozzle is changed, thereby changing the retracted length between the inner and outer centrifugal nozzles, and the effect of the retracted length on longitudinal combustion instability in the combustion chamber is studied.

[0120] The above describes preferred embodiments of the present application, but the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, various equivalent transformations of the technical solutions of the present application can be made, and these equivalent transformations all belong to the protection scope of the present application.

Claims

1. A liquid-liquid coaxial centrifugal nozzle combustion instability active control injection panel, characterized by: The upper cover plate, the internal centrifugal nozzle and the external centrifugal nozzle are included; The upper cover plate includes a cylindrical cavity A, a cylindrical cavity B and a propellant supply flow channel; The cylindrical cavity A and the cylindrical cavity B are coaxially arranged from top to bottom; The propellant supply flow channel includes a propellant A supply flow channel, a propellant B supply flow channel and a secondary propellant supply flow channel; The external centrifugal nozzle includes an external swirl chamber, an external straight section and a jet bottom plate; The external straight section is coaxially and integrally arranged at the bottom of the external swirl chamber, and the bottom is in communication with the combustion chamber; The top outer wall of the external swirl chamber is sealingly connected with the bottom inner wall of the cylindrical cavity A, and the bottom outer wall of the external swirl chamber is sealingly connected with the middle part of the cylindrical cavity B, so that the cylindrical cavity A located at the top of the external swirl chamber forms a sealed propellant A collecting cavity, and the cylindrical cavity B located at the outer periphery of the external swirl chamber forms a sealed propellant B collecting cavity; the external swirl chamber is in communication with the propellant B supply flow channel through an outer tangential hole; the cylindrical cavity B located at the outer periphery of the external straight section forms a sealed secondary propellant collecting cavity; The propellant A supply flow channel is used for conveying liquid propellant A to the propellant A collecting cavity; The propellant B supply flow channel is used for conveying liquid propellant B to the propellant B collecting cavity; The secondary propellant supply flow channel is used for conveying liquid or gas propellant A and / or propellant B to the secondary propellant collecting cavity; The jet bottom plate is sealingly and detachably connected with the combustion chamber; a plurality of secondary propellant injection holes are uniformly arranged on the jet bottom plate along the circumference of the outer periphery of the external straight section, and each secondary propellant injection hole is in communication with the secondary propellant collecting cavity and the combustion chamber; The internal centrifugal nozzle is coaxially and detachably arranged in the external centrifugal nozzle, and the internal centrifugal nozzle includes an internal swirl chamber and an internal straight section coaxially arranged at the bottom of the internal swirl chamber; The top of the internal swirl chamber is in communication with the propellant A collecting cavity through an inner tangential hole; A pressure measuring device and a photomultiplier tube are arranged in the combustion chamber; The pressure measuring device includes a static pressure sensor and three high-frequency dynamic pressure sensors; The static pressure sensor can be used for monitoring the static pressure in the combustion chamber; The three high-frequency dynamic pressure sensors are arranged along the longitudinal direction of the combustion chamber, and are respectively used for monitoring the head high-frequency pressure, the middle high-frequency pressure and the tail high-frequency pressure of the combustion chamber at each time; The photomultiplier tube collects the CH * The flame emission intensity, and then the heat release pulsation in the combustion chamber. Through the cooperation of the pressure measuring device and the photomultiplier tube, whether longitudinal combustion instability occurs in the combustion chamber can be monitored.

2. The liquid-liquid coaxial centrifugal nozzle combustion instability active control injection faceplate of claim 1, wherein: The judgment method of longitudinal combustion instability in the combustion chamber is as follows: Step 1, judging combustion instability: when the head high-frequency pressure, the middle high-frequency pressure and the tail high-frequency pressure all periodically change, the oscillation period, the oscillation frequency and the oscillation amplitude T1 of the head high-frequency pressure are recorded; then, the ratio K of the oscillation amplitude T1 to the static pressure P1 of the combustion chamber is calculated; when K≥5%, it is considered that combustion instability occurs in the combustion chamber; Step 2, preliminarily judging longitudinal combustion instability: according to the head high-frequency pressure, the middle high-frequency pressure and the tail high-frequency pressure at different times, a longitudinal pressure time phase curve of the combustion chamber is drawn, and whether combustion instability occurs longitudinally in the combustion chamber is preliminarily judged. Step 3, secondary determination of longitudinal combustion instability: when the combustion chamber is preliminarily determined to have longitudinal combustion instability in step 2, the phase difference Δ between the oscillation phase of the high-frequency pressure and the phase of the heat release pulse is compared, and when Δ<90°, it is determined that the combustion chamber has longitudinal combustion instability.

3. The liquid-liquid coaxial centrifugal nozzle combustion instability active control injection faceplate of claim 2, wherein: When the combustion chamber has longitudinal combustion instability, the secondary propellant injection flow rate of each secondary propellant injection hole is actively and dynamically adjusted according to the current value of K until the combustion chamber achieves stable combustion.

4. The liquid-liquid coaxial centrifugal nozzle combustion instability active control injection faceplate of claim 3, wherein: The active and dynamic adjustment method of the secondary propellant injection flow rate in each secondary propellant injection hole includes the following steps: Step 4-1, setting K value levels: the K values are set to 6 levels in order from small to large; Step 4-2, setting flow amplitude L levels: the secondary propellant injection flow rate is a sinusoidal pulse jet with flow amplitude L; the flow amplitude L is set to 6 levels in order from small to large; Step 4-3, drawing a K-L correspondence table: the 6 levels of K values in step 4-1 are corresponded to the 6 levels of flow amplitude L values in step 4-2 one by one, and a K-L correspondence table is drawn; Step 4-4, selecting flow amplitude L: according to the value of K calculated in step 1, the corresponding flow amplitude L is selected from the K-L correspondence table in step 4-3; Step 4-5, determining the secondary propellant injection flow rate: each secondary propellant injection hole uses the oscillation frequency of the head high-frequency pressure in step 1 as the pulse frequency, and uses the flow amplitude L selected in step 4-4 as the pulse amplitude to perform sinusoidal pulse jet of the secondary propellant.

5. The liquid-liquid coaxial centrifugal nozzle combustion instability active control injection faceplate of claim 4, wherein: In step 4-1, the 6 levels of K values are 0%-5%, 5%-10%, 10%-20%, 20%-30%, 30%-40% and 50% respectively; in step 4-2, the 6 levels of flow amplitude L values are 0%F, 2%F, 4%F, 6%F, 8%F and 10%F respectively; wherein, when the secondary propellant is propellant A, F is the total flow rate of propellant A in the propellant A supply flow channel; when the secondary propellant is propellant B, F is the total flow rate of propellant B in the propellant B supply flow channel.

6. The liquid-liquid coaxial centrifugal nozzle combustion instability active control injection faceplate of claim 4, wherein: It also includes step 4-6, finding the optimal flow amplitude L, which includes the following steps: Step 4-6a, calculating the value of K': when the secondary propellant injection flow rate determined in step 4-5 is set for a certain period of time, the oscillation amplitude T2 of the head high-frequency pressure at this time and the static pressure P2 of the combustion chamber at this time are extracted, and the value of K' = T2 / P2 is calculated; Step 4-6b, judging the combustion stability: when the value of K' is less than the set expected value, it is considered that the combustion instability is suppressed; Step 4-6c, reducing the flow amplitude L: assuming that the 6 levels of the ratio K in step 4-1 are K1, K2, K3, K4, K5 and K6 in ascending order; and assuming that the ratio K calculated in step 1 is K i ; wherein, 1≤i≤6; after the combustion instability is determined to be suppressed in step 4-6b, the flow amplitude L' is selected according to the ratio K calculated in step 1, specifically: A, when i=1, the flow amplitude L corresponding to K1 in the K-L correspondence table is the optimal flow amplitude L; B. When 2≤i≤6, select K from the K-L correspondence table in step 4-3 i -1 should be compared with the flow amplitude L, as the selected flow amplitude L' Step 4-6d, repeat step 4-6a to step 4-6c, and take the selected minimum flow amplitude L' as the optimal flow amplitude L before combustion instability is inhibited; then, each secondary propellant injection hole is subjected to sinusoidal pulsed jet of secondary propellant with the oscillation frequency of the head high-frequency pressure in step 1 as the pulse frequency and the optimal flow amplitude L' selected in step 4-6c or step 4-6d as the pulse amplitude.

7. The liquid-liquid coaxial centrifugal nozzle combustion instability active control injection faceplate of claim 1, wherein: The inner rotating flow chamber top of the inner centrifugal nozzle and the top of the cylindrical cavity A are connected by a tenon and mortise cooperation of a boss and a groove, so as to realize axial positioning of the inner centrifugal nozzle. The inner rotating flow chamber top of the inner centrifugal nozzle and the top of the cylindrical cavity A are connected by a tenon and mortise cooperation of a boss and a groove, so as to realize axial positioning of the inner centrifugal nozzle.

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