• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Experimental study of the influence of annular nozzle on acoustic characteristics of detonation sound wave generated by pulse detonation engine

    2022-10-26 09:46:48YangKang康楊NingLi李寧XiaoLongHuang黃孝龍andChunShengWeng翁春生
    Chinese Physics B 2022年10期
    關(guān)鍵詞:春生李寧

    Yang Kang(康楊), Ning Li(李寧), Xiao-Long Huang(黃孝龍), and Chun-Sheng Weng(翁春生)

    National Key Laboratory of Transient Physics,Nanjing University of Science and Technology,Nanjing 210094,China

    Keywords: pulse detonation engine,annular nozzle,detonation sound wave,acoustic characteristics

    1. Introduction

    The pulse detonation engine(PDE)has been recently recognized as an innovative aerospace propulsion technology.[1,2]It is a kind of pulse jet engine that obtains thrust by high temperature and high pressure burned products generated by the periodic detonation wave. PDEs potentially provide significant advantages of high thermal cycle efficiency, mechanical simplicity, higher thrust-to-weight ratios, lower cost, and a wide working scope.[3]The detonation sound wave is produced by the pressure pulsation of the medium caused by a series of complex waves such as shock waves outside the detonation tube and jet induced shock waves during the detonation process.[4]The preliminary research results show that the noise generated by manned aircraft with PDEs as the propulsion system is equivalent to the noise level of B–1B bombers.Therefore, when PDEs are employed as the propulsion system,the high-intensity noise and vibration generated during its operation will pose a serious threat to the aircraft’s structural sonic fatigue, overall performance, and safety. From another perspective,PDEs can repetitively and reliably generate highintensity acoustic energy. The acoustic characteristic of the detonation sound wave makes PDEs attractive for applications that require substantial acoustic energy.[5]

    The nozzle is a key component of PDE’s research.[6,7]Nozzles directly affect the propulsion performance of the PDE and change the acoustic characteristics of the detonation sound wave,thereby affecting the safety of the aircraft. The annular nozzle is a type of nozzle with a relatively special structure.In the research of rocket engines, it is found that the annular nozzle has great potential for improving thrust and specific impulse performance.[8]The research on the influence of the annular nozzle on acoustic characteristics of the detonation sound wave can not only meet the fundamental research needs of PDE propulsion but is also expected to provide a new development path for the military application of pulse sound wave in special areas.

    The research on the detonation sound wave was first carried out in the early 21st century, thereby, there is relatively few research in the field of detonation sound wave. The preliminary studies have confirmed that nozzles are extremely effective in the acoustic performance of PDE. Allgoodet al.[9–12]conducted an experimental study on the directivity of the acoustic characteristics of gaseous ethylene fueled PDE and explored the influence of experimental parameters such as filling fraction,ignition frequency,and nozzle structures on detonation sound wave. The experimental results showed that the sound pressure level(SPL)in upstream and sideline measurement angles is lower than the downstream angles and the overall SPL obtained an increment with fill fraction and ignition frequency increasing. The results also suggested that the acoustic characteristics are sensitive to the exit geometry,nozzle length, and area ratio. Results from the nozzle testing indicate that the converging nozzle has a global reduction in overall SPL at all fill fractions,while diverging nozzles experienced overall SPL reductions in only the downstream angles.The chevron nozzles had only a moderate effect on overall SPL.The perforated nozzle increased overall SPL at upstream angles and slightly decreased at the downstream angles. The straight cylindrical ejector had a global reduction on overall SPL at all directivity angles,and the maximum attenuation levels of 6.8 dB were observed under certain conditions. Huanget al.[13]also explored the far-field noise radiation characteristics of ejectors installed on a PDE.The experimental results also showed that ejectors could decrease the peak SPL and the maximum reduction was approximately 8.5 dB.Shawet al.[14]tested acoustic signals of the single tube to four tubes PDE fueled by hydrogen within 12 feet (1 ft=3.048×10-1m), and compared the effects of five acoustic suppression designs such as converging nozzle,notched nozzles,secondary air jet,split exit,and Helmholtz resonator on SPL.Kanget al.[15]investigated the acoustic characteristics of a PDE with an ellipsoidal reflector. The ellipsoidal reflector can create a focal zone with very high pressure at the PDE axis and obviously reduce the pressure attenuation in the PDE downstream direction.

    In addition to studying the acoustic characteristics of various nozzles and mufflers installed at the outlet of the PDE,the acoustic characteristics of a hybrid pulse detonation engine(HPDE), which is constituted of a compressor, a PDE, and a turbine,were also studied. Zhenget al.[16]experimentally investigated the acoustic characteristics of an HPDE under several operating conditions. The results showed that the SPL of HPDE is less than that of PDE about 4 dB,and the peak SPL reduces by about 2 dB.Huanget al.[17]conducted far field jet noise measurements of HPDE under different operating frequencies. The results showed that the turbine interacting with PDE could decrease the peak SPL approximately 14.2 dB.

    In the research of the formation mechanism and propagation characteristics of detonation sound wave, Xuet al.[18,19]studied the formation and propagation process of PDE sound by combining the experimental and numerical methods. The effects of different tubes and loading conditions on PDE sound were also studied. Huanget al.[20]numerically and experimentally explored the mechanism and characteristics of noise propagation out of multiple-tube PDE.Kanget al.[21]explored the acoustic characteristics of detonation sound wave propagating in enclosed sapce. The experimental results indicated that the PSL and duration of detonation sound wave in enclosde space is higher than that in open space.

    In this study, experimental investigations are performed on a gas–liquid two-phase PDE to explore the influence of the geometry of annular nozzles on the acoustic characteristics of the detonation sound wave. A PDE with diverging nozzle is also investigated as the baseline condition. The acoustic characteristics of PDE with different annular nozzles, including peak sound pressure,directivity,and A duration,are analyzed.

    2. Experimental setup

    The experimental system is composed of a detonation tube, fuel/oxidizer supply subsystem, an ignition device, an acoustic measurement subsystem, and various nozzles. A schematic of the experimental system is demonstrated in Fig.1.

    Fig. 1. Schematic diagram of the experimental setup: 1. data acquisition and processing system,2. A/D converter,3. microphones,4. spark plug,5.ignition controller.

    The detonation tube is made of a 304 stainless steel pipe which is 1700 mm in length and 80 mm in inner diameter.It consists of a mixing chamber, an ignition chamber, and a detonation chamber. A Venturi tube is installed in the mixing chamber and a spark plug is installed in the ignition chamber.A number of orifice plates are inserted into the front of the detonation chamber to accelerate the deflagration-to-detonation transition process. The 92#gasoline and nitrogen diluted oxygen are selected as fuel and oxidizer.The oxidizer used during experiments is 60% nitrogen and 40% oxygen by mole fraction. In the fuel/oxidizer supply subsystem, the compressed oxygen and nitrogen are delivered into the mixing chamber controlled by electromagnetic valves from the tangential direction. The liquid gasoline fuel in the tank is transported into an atomizing spray nozzle,which is installed at the closed end of the detonation tube, through a separate duct by nitrogen extrusion. The fuel is injected into the mixing chamber of the detonation tube after first being atomized by the atomizing spray nozzle when the electromagnetic valve of the fuel supply system is opened. Part of the fuel directly passes through the throat of the Venturi tube, and the other part of the fuel droplets are injected on the smooth surface of the Venturi tube to form a thin oil film. During oxidizer gas flow through the Venturi’s throat,gas velocity accelerates due to the contraction of the Venturi,and oil film on the Venturi surface is atomized twice. Thus, the liquid fuel and gas oxidizer are fully mixed in the mixing chamber to form a well atomized and evenly mixed combustible mixture to fill the ignition chamber and detonation chamber. The Sauter mean diameter of gasoline droplets in the mixing chamber are measured in the range of 50 μm to 100 μm. The equivalence ratio and the mass flow of the fuel and oxidizer mixture can be adjusted by controlling the filling pressure. In the present work, the filling pressure is set as 0.8 MPa and the equivalence ratio is maintained to be stoichiometric,φ=1. The fill fraction,which was defined as the ratio of the volume of the detonation tube filled with a combustible mixture prior to ignition to the overall volume of the tube, is held constant at 1.0. The fuel and oxidizer mixtures are ignited by a spark plug which delivers 1.5-J energy per spark,and the ignition frequency can be controlled easily by a signal generator. The PDE is fired at a frequency of 5 Hz in all experiments.

    The acoustic measurement subsystem is specifically designed for obtaining acoustic signals.Four PCB precision condenser microphones (Model 377A12) are adopted for acoustic measurement. The dynamic range(3%distortion limit)of the microphones is 180 dB (re 20 μPa) and the microphones should be used with PCB 426B03 preamplifier. The microphones should be calibrated with GRAS 42AB sound pressure calibrator before use to determine their real-time sensitivity to avoid system errors caused by local wind speed,temperature,and humidity. The calibration accuracy of the sound pressure calibrator is 114 dB±0.2 dB (re 20 μPa). The acoustic signals are converted to a digital signal via an A/D converter and acquired by an NI PXIe-1062Q multi-channel high-speed data acquisition system at 500 k Samples/s for all microphones simultaneously by using a LabView interface program. The microphones are arranged outside the detonation tube at theθdirectivity angle at the same height as the central axis of the detonation tube, and the distance from the tube exit isr, the directivity angleθand the distancercan be changed according to the experimental requirements. The directivity angle is defined as the angle from the microphone concerning the detonation tube centerline with 0°being assigned to be the downstream direction. The microphones were arranged at directivity angles of 0°, 30°, 60°, and 90°at the positionr=10 m,15 m,20 m,and 25 m in the present study.

    Figure 2 shows the geometry schematic of four nozzles explored in this study, including one diverging nozzle#1 and three annular nozzles #2, #3, and #4. The parameters are shown in Table 1. The annular nozzles are composed of an outer diverging surface and an inner cone. For the four nozzles,the inlet diameterd1is given as the diameter of the detonation tube as 80 mm and the lengthL1is kept as 300 mm.The exit diameterd2of the diverging nozzle is 220 mm. The geometry parameters of the outer diverging surface are the same as diverging nozzle #1. The length of inner coneL2remains as 300 mm,the key difference is the bottom diameter of inner coned3, which is 80, 110, and 150 mm. The ratios of inner cone diameterd3to detonation tube exit diameterd2, which is represented byDR, are 0.36, 0.5, and 0.68 separately. As shown in Fig.3,the inner cone is connected to the flange plate by the reinforcing rib, and is connected with the outlet of the diverging surface through the flange. The inlet of the nozzles are also attached to the open end of the detonation tube via a flange connection.

    Fig. 2. The geometry schematic diagram of nozzles, (a) diverging nozzle,(b)annular nozzle.

    Table 1. Geometry parameters of the nozzles(in unit: mm).

    Fig.3. Views of the annular nozzle: (a)main view,(b)left view.

    3. Results and discussion

    The repeatability experiments are performed and the equivalence ratio of the fuel and oxidizer mixture,fill fraction,and the operation frequency are kept consistent in all experiments. As has been explored in previous work,[21]the detonation sound wave generated by a PDE exhibits the characteristic of typical impulse noise. As shown in Fig. 4, the detonation sound wave is mainly produced through two sources:the shock sound wave induced by the shock wave degenerated from the detonation wave and the jet sound wave produced during the blowdown of the high-temperature and highpressure detonation products.[12]

    Fig.4. Schematic diagram of detonation sound wave.[5]

    A typical pressure history of detonation sound wave generated by PDE with an annular nozzle is selected for analyses shown in Fig. 5. The sound pressure of the shock sound wave and the jet sound wave are represented byp1andp2respectively. The time period corresponds to the A duration is represented byt+,which would be analyzed in Subsection 3.3.

    Fig.5.Typical pressure history of detonation sound wave generated by PDE with annular nozzle.

    3.1. Peak sound pressure of detonation sound wave

    Figure 6 shows the variations of peak sound pressure of the detonation sound wave at all directivity angles. The peak sound pressure of the detonation sound wave decays with the rise of the propagation distance at all directivity angles. However,the effects of annular nozzles on the peak sound pressure of the detonation sound wave vary with directivity angle.

    As shown in Fig.6(a),the installation of annular nozzles exhibits a reduction in the peak sound pressure at 0°. The reduction effect on the peak sound pressure is most prominent under the installation of annular nozzle #4, and a maximum attenuation of 1608.7 Pa was recorded at 10 m. With the increase inDRvalue,the reduction effect of the annular nozzle gradually becomes stronger. Figure 6(b)shows the variations of the peak sound pressure at 30°. It exhibits the trend seen before at 0°,that the peak sound pressure was reduced by the annular nozzles. And the most obvious reduction effect was seen under the installation of annular nozzle#4. Here,a maximum attenuation of 1617.4 Pa was recorded at 10 m. It can be observed from Fig.6(c)that the peak sound pressure of the detonation sound wave at 60°achieved an amplification of annular nozzles#2 and#4 but a reduction of the annular nozzle#3. The amplification effect is most prominent for the annular nozzle#4,the maximum amplification condition occurs at 10 m,where an increment of 603.5 Pa is achieved. Figure 6(d)plots the peak sound pressure of the detonation sound wave at 90°. The effect of annular nozzles on peak sound pressure at 90°is opposite of the effect at 0°and 30°.As seen in Fig.6(d),the peak sound pressures are now amplified by annular nozzles, and the highest peak sound pressure is obtained when the annular nozzle #4 is installed, which increases the peak sound pressure by 881.3 Pa at 10 m. With the increase inDRvalue,the amplification effect of the annular nozzle gradually becomes stronger.

    Fig.6. The effect of nozzles on peak sound pressure of the detonation sound wave at all directivity angles: (a)0°,(b)30°,(c)60°,and(d)90°.

    Heet al.[22]found that the wave amplitude is much higher at the locations a little off from the centerline.They conducted numerical simulations of the external flow field of PDE. The numerical results showed the interaction between the shock wave and the vortex ring to produce the higher peak and lower trough at the locations close. The annular nozzle is composed of a diverging nozzle and a solid inner cone, and the apex of the solid inner cone is located on the centerline of the divergent nozzle. The inner cones may have a significant influence on the flow field outside the detonation tube, which changes the propagation direction of the shock wave and the following high-temperature and high-pressure detonation gas jet in the nozzle. Due to the change in the propagation direction of the gas jet,the vortex ring is developed near the outlet of annular nozzles. Under this circumstance, the vortex ring is located farther from the central axis than when no annular nozzle exists. As a result, changes in the direction of the shock wave and the position of the vortex ring lead to changes in the interaction environment between the shock wave and the vortex ring, resulting in the deflection of the position of the highest sound pressure away from the central axis.Compared with the diverging nozzle,the acoustic energy of the detonation sound wave is weakened along the tube axis and reinforced perpendicular to the tube axis by the inner cone of the annular nozzle.As the inner cone diameter(DRvalue)increases,the discharge area of the detonation products decreases,and the distance between the exit of the annular nozzle and the tube axis enlarges,which further changes the acoustic energy distribution outside the detonation tube. The case corresponding to the annular nozzle#4 with the maximumDRvalue exhibits the extremes in peak sound pressure reduction and amplification.

    3.2. Directivity of detonation sound wave

    A thorough understanding of the directivity of the detonation sound wave is beneficial to control the emission angle of detonation sound wave for better utilization as intensive sound equipment. To simplify the study of the directivity change of detonation sound wave,the peak sound pressure of detonation sound wave is normalized as

    As seen from Fig. 7(a), the detonation sound wave with the diverging nozzle#1 at different propagation distances has the same directivity property. The peak sound pressure of the detonation wave at 30°is higher than that at another directivity angle,which indicates that the detonation sound wave of PDE with the diverging nozzle#1 has a significant directivity at 30°angle. It can also be noted that the lowest peak sound pressure is found at 90°. This suggests that most of the acoustic energy is focused near the tube axis as PDE is installed with diverging nozzle.

    Fig.7. The effect of nozzles on the directivity of detonation sound wave: (a)diverging nozzle#1,(b)annular nozzle#2,(c)annular nozzle#3,(d)annular nozzle#4.

    Figure 7(b)shows the directivity of the detonation sound wave with the annular nozzle#2.It can be seen that at the measuring points of 10 m,15 m,and 20 m,the peak sound pressure of the detonation wave at 60°is the highest,and its values are respectively 2.21, 3.69, and 3.78 times the peak sound pressure at 0°. At the measuring point of 25 m, the peak sound pressure of the detonation sound wave at 90°is the highest,and its value is 2.88 times the peak sound pressure at 0°. This indicates that the annular nozzle has changed the directivity of the detonation sound wave. The directivity of the detonation sound wave at the measuring points of 10 m,15 m,and 20 m is changed from 30°to 60°. The directivity of the detonation sound wave at 25 m is changed from 30°to 90°. At the same time, the annular nozzle also changed the lowest peak sound pressure from 90°to 0°.

    Figure 7(c)shows the directivity of the detonation sound wave with the annular nozzle#3.It has a significant difference from the directivity of the detonation sound wave with annular nozzle#2. The highest peak sound pressure is obtained at 90°while the lowest is obtained at 0°. The directivity of 90°angle is consistent and the peak sound pressure ratios of the detonation sound wave are 4.76, 6.19, 6.04, and 4.26 at the measuring point from 10 m to 25 m,which are larger than that of the annular nozzle#2. The increase of the peak sound pressure ratio suggests that the annular nozzle #3 further reduces the acoustic energy of the detonation sound at 0°.

    Figure 7(d)shows the directivity of the detonation sound wave with annular nozzle#4.The detonation sound wave with annular nozzle#4 has the same directivity as the annular nozzle #3, at a directivity angle of 90°. The minimum value of the peak sound pressure of the detonation sound wave is still at 0°, and the peak sound pressure increases gradually with the increase of directivity angle. The ratios of the peak sound pressure at 90°are further increased compared to annular nozzle#3,which are 6.51,7.59,8.46,and 8.92.The ratios of peak sound pressure are reduced at 30°compared to that of the annular nozzle#3,the ratio of peak sound pressure of detonation sound wave at 60°and 90°rises rapidly to a higher value than the value in the corresponding angle with the annular nozzle#3. It indicates that compared to the annular nozzle#2 and#3,the annular nozzle #4 further attenuates the peak sound pressure at 0°and 30°and concentrates more acoustic energy at 60°and 90°, which makes the directivity of 90°angle more prominent with the annular nozzle#4.

    According to the above analysis, the annular nozzle greatly influences the directivity of the detonation sound wave.The peak sound pressure of the detonation sound wave with the annular nozzle at 30°, 60°, and 90°are all higher than that at 0°. Additionally,the directivity of the detonation sound wave also changes with theDRvalue increasing. Hence, the acoustic energy distribution of the detonation sound wave is altered by the annular nozzles,which amplify the acoustic energy in a direction perpendicular to the tube axis and weaken it along the direction of the tube axis.

    3.3. A duration of detonation sound wave

    Hearing impairment and loudness are both related to the acoustic energy of the detonation sound wave. The effective duration and amplitude of peak sound pressure play an equal role in evaluating the acoustic energy of impulse noise. Thus,the duration becomes another physical characteristic. The A duration is the time it takes for an initial or principal pressure wave to reach its positive peak and return to ambient pressure,which is represented byt+as shown in Fig.5. The A duration primarily indicates the amount of energy emitted by the noise source.

    Figure 8(a)shows the A duration of the detonation sound wave with nozzles at 0°. The A duration of the detonation sound wave with nozzles at 0°exceeds 2 ms. Combined with the analysis of the pressure history of the detonation sound wave, it can be seen that A duration of the detonation sound wave at 0°is determined by the duration of shock sound wave induced by the shock wave degenerating from the detonation wave and jet sound wave induced by the high temperature and high pressure jet following the detonation wave. This indicates that the pressure value of the shock sound wave does not drop to negative pressure when the jet acoustic wave arrives and causes a rise in the pressure value. The effect of theDRof annular nozzles on the A duration at 0°is different. The annular nozzle #3 and #4 increase A duration of detonation sound wave while the annular nozzle #2 reduces A duration at 0°. The A duration of detonation sound wave with annular nozzle #2, #3, and #4 at 0°are gradually increased with the rise of propagation distance. This is because the detonation sound wave at 0°is attenuated by the annular nozzle,and the positive pressure is enlarged by the annular nozzle.

    Figure 8(b) shows the A duration of detonation sound wave at 30°. The A duration of the detonation sound wave at 30°is distributed in the range of 0.4 ms to 0.7 ms and 2.5 ms to 3.1 ms.The A duration of detonation sound wave with annular nozzle #4 at all measuring points are determined by both the shock sound wave and the jet sound wave,so as the detonation sound wave with annular nozzle#3 at 10 m and 15 m. In these circumstances, the A duration of the detonation sound wave ranges from 2.5 ms to 3.1 ms.The A duration of the detonation sound wave with diverging nozzle#1 and annular nozzle#2 at all measuring points are determined by the shock sound wave only,so as the detonation sound wave with annular nozzle#3 at 20 m and 25 m. As a result,the A duration of the detonation sound wave under these conditions is relatively short, in the range from 0.4 ms to 0.7 ms. The annular nozzles increase the A duration of the detonation sound wave at 30°. The A duration of detonation sound wave with annular nozzles at 30°is decreased gradually with propagation distance increases. The reason is that the acoustic energy of the detonation sound wave with annular nozzles at 30°has been enhanced. As the propagation distance of the detonation sound wave increases, the peak sound pressure of the shock sound wave attenuates. This results in the time interval between the shock sound wave and the jet sound wave being shortened,thus reducing the A duration.

    Fig.8. The effect of nozzles on A duration of detonation sound wave.

    Figure 8(c)shows the A duration of the detonation sound wave with nozzles at 60°. The A duration of the detonation sound waves with nozzles at different propagation distances at 60°are all in the range from 0.5 ms to 0.9 ms. The A duration of the detonation sound wave with annular nozzles at 60°is only determined by the shock sound wave,and it gradually decreases as the distance increases.

    Figure 8(d)shows the A duration of the detonation sound wave with nozzles at 90°. The A duration of detonation sound wave at 90°is distributed in the range from 0.3 ms to 0.7 ms.The annular nozzles#2,#3,and#4 increase the A duration at 90°. The A duration of the detonation sound wave with annular nozzles at 90°also decrease with increasing propagation distance of the detonation sound wave.

    It is clear from the above analysis that annular nozzles influence the A duration of the detonation sound wave. The A duration increases with the propagation distance at 0°and decreases with the propagation distance at 30°,60°,and 90°.The most important finding is that annular nozzles can increase the A duration of detonation sound wave at 90°.

    4. Conclusions

    In this study, the influence of the geometry of the annular nozzle on acoustic characteristics of a PDE is experimentally investigated. Experimental results demonstrate that the annular nozzles can amplify the peak sound pressure of the detonation sound wave at 90°while reducing it at 0°and 30°.The lowest peak sound pressure of the detonation sound wave with the annular nozzle occurs at 0°. The annular nozzles can also shift the directivity of the detonation sound wave from 30°to 90°. The annular nozzles can increase the A duration of the detonation sound wave at 90°. The changes of the acoustic characteristics of detonation sound waves demonstrate that the acoustic energy distribution of the detonation sound wave is altered by the annular nozzles,which amplify the acoustic energy in a direction perpendicular to the tube axis and weaken it along the direction of the tube axis. When PDEs are employed as high-intensive sound sources,the annular nozzles can assist PDEs in generating the high-intensity sound wave and emit it in multiple directions regardless of the fixed installation location.The research results can promote the mechanism research of PDE’s acoustical problems and provide experimental verification for the military application of detonation sound waves.

    Acknowledgements

    Project supported by the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20220919) and the National Key Laboratory of Transient Physics Foundation Project,China(Grants No.6142604210203).

    猜你喜歡
    春生李寧
    回望祖山圖
    What Is Guochao?
    Dynamic modeling and aperiodically intermittent strategy for adaptive finite-time synchronization control of the multi-weighted complex transportation networks with multiple delays?
    曹春生作品
    占春生作品
    Progress in quantum well and quantum cascade infrared photodetectors in SITP?
    跌宕起伏“李寧”
    商界評論(2017年5期)2017-05-17 18:44:16
    曹春生
    不認(rèn)賬
    雜文選刊(2014年12期)2014-11-17 03:53:48
    腳踏實(shí)地再創(chuàng)輝煌
    雕塑(1997年1期)1997-06-26 11:16:58
    亚洲av男天堂| 久久精品久久久久久久性| 大片电影免费在线观看免费| 免费高清在线观看视频在线观看| 另类精品久久| 亚洲精品国产色婷婷电影| 日韩不卡一区二区三区视频在线| 国产av码专区亚洲av| 精品少妇黑人巨大在线播放| 午夜精品国产一区二区电影| 国产精品久久久久成人av| videossex国产| 男女边吃奶边做爰视频| 两性夫妻黄色片 | 另类亚洲欧美激情| 国产av一区二区精品久久| 熟女av电影| 看免费成人av毛片| 久久av网站| 赤兔流量卡办理| 久久久久久人妻| 中文字幕免费在线视频6| 熟女人妻精品中文字幕| 97精品久久久久久久久久精品| 中文字幕精品免费在线观看视频 | 亚洲精品成人av观看孕妇| 亚洲色图综合在线观看| 日韩中文字幕视频在线看片| 亚洲精品久久久久久婷婷小说| 一级爰片在线观看| 欧美 日韩 精品 国产| 国产亚洲精品久久久com| 成人国产麻豆网| 亚洲第一区二区三区不卡| 国产日韩欧美亚洲二区| 成年人午夜在线观看视频| 亚洲av男天堂| 午夜日本视频在线| 免费高清在线观看日韩| kizo精华| 亚洲精品国产av蜜桃| 最近的中文字幕免费完整| 亚洲一级一片aⅴ在线观看| 高清黄色对白视频在线免费看| 久久久久久久亚洲中文字幕| 又黄又粗又硬又大视频| 在线观看国产h片| 香蕉国产在线看| 大陆偷拍与自拍| 国产精品国产av在线观看| 日韩 亚洲 欧美在线| av一本久久久久| 啦啦啦在线观看免费高清www| 日本与韩国留学比较| 国产欧美亚洲国产| 欧美精品高潮呻吟av久久| 亚洲欧美日韩另类电影网站| 亚洲,一卡二卡三卡| 在线观看三级黄色| 国产亚洲欧美精品永久| 亚洲精品乱久久久久久| 精品一区二区三区四区五区乱码 | 午夜福利影视在线免费观看| 精品亚洲成国产av| 捣出白浆h1v1| 免费看不卡的av| 又黄又粗又硬又大视频| 亚洲图色成人| 免费观看无遮挡的男女| 九九爱精品视频在线观看| 久久这里有精品视频免费| 欧美xxⅹ黑人| 欧美精品国产亚洲| 亚洲国产av新网站| 在线亚洲精品国产二区图片欧美| a级毛片在线看网站| 欧美97在线视频| 亚洲欧美一区二区三区国产| 久久国产亚洲av麻豆专区| 国国产精品蜜臀av免费| 日本wwww免费看| 卡戴珊不雅视频在线播放| 亚洲欧美日韩另类电影网站| 宅男免费午夜| av福利片在线| 午夜91福利影院| 精品人妻一区二区三区麻豆| 久久久久久久久久人人人人人人| 26uuu在线亚洲综合色| 亚洲欧洲精品一区二区精品久久久 | 免费看不卡的av| av网站免费在线观看视频| 爱豆传媒免费全集在线观看| 久久久久精品性色| 色5月婷婷丁香| 看免费成人av毛片| 少妇被粗大的猛进出69影院 | 日本av免费视频播放| 国产 一区精品| 国产熟女欧美一区二区| 精品国产一区二区三区久久久樱花| videosex国产| 免费女性裸体啪啪无遮挡网站| av有码第一页| 看免费成人av毛片| 亚洲国产精品国产精品| 久久人人97超碰香蕉20202| 国产又爽黄色视频| 亚洲成av片中文字幕在线观看 | 国产淫语在线视频| 亚洲成av片中文字幕在线观看 | 成人午夜精彩视频在线观看| 捣出白浆h1v1| 亚洲国产精品一区二区三区在线| 国产一区二区三区综合在线观看 | 日日摸夜夜添夜夜爱| 国产片特级美女逼逼视频| a 毛片基地| 亚洲欧美日韩另类电影网站| 最近的中文字幕免费完整| 最近中文字幕高清免费大全6| 国产亚洲最大av| 国产精品欧美亚洲77777| 国产激情久久老熟女| 欧美精品av麻豆av| 久久精品久久精品一区二区三区| 美女福利国产在线| 老女人水多毛片| 99视频精品全部免费 在线| 日本wwww免费看| av电影中文网址| 在线观看一区二区三区激情| 最新的欧美精品一区二区| 亚洲情色 制服丝袜| 黄色 视频免费看| 久久久久久久久久久免费av| 久久久国产一区二区| 男人爽女人下面视频在线观看| 国产又爽黄色视频| 男人操女人黄网站| 欧美人与性动交α欧美软件 | 国产亚洲最大av| 国产无遮挡羞羞视频在线观看| 亚洲,欧美,日韩| 午夜av观看不卡| 久久 成人 亚洲| 涩涩av久久男人的天堂| 国产黄色免费在线视频| 男男h啪啪无遮挡| 久久久a久久爽久久v久久| 免费观看av网站的网址| 久久人人爽av亚洲精品天堂| 国产亚洲av片在线观看秒播厂| 国产有黄有色有爽视频| 亚洲情色 制服丝袜| 免费黄网站久久成人精品| 亚洲成色77777| 一本色道久久久久久精品综合| 久久国内精品自在自线图片| 两个人免费观看高清视频| 免费人妻精品一区二区三区视频| 国产成人a∨麻豆精品| 久久精品国产亚洲av天美| 人人妻人人澡人人爽人人夜夜| 久久人妻熟女aⅴ| 国产成人精品在线电影| 成年人午夜在线观看视频| 成年人午夜在线观看视频| 成年av动漫网址| 高清在线视频一区二区三区| 少妇被粗大的猛进出69影院 | 久久久亚洲精品成人影院| 久久久久精品久久久久真实原创| 大码成人一级视频| 日日摸夜夜添夜夜爱| 国产老妇伦熟女老妇高清| 久久久久久久大尺度免费视频| 天天影视国产精品| 91精品三级在线观看| 免费大片18禁| 亚洲精品国产av成人精品| 亚洲欧美一区二区三区国产| 亚洲国产毛片av蜜桃av| 岛国毛片在线播放| 最近中文字幕2019免费版| 汤姆久久久久久久影院中文字幕| 婷婷色综合大香蕉| 久久久国产一区二区| 久久国产亚洲av麻豆专区| 侵犯人妻中文字幕一二三四区| 久久人人97超碰香蕉20202| 日韩在线高清观看一区二区三区| 亚洲成人av在线免费| 日韩av在线免费看完整版不卡| 只有这里有精品99| 亚洲国产av影院在线观看| 亚洲欧洲日产国产| 丰满少妇做爰视频| 亚洲av综合色区一区| 青春草视频在线免费观看| 国产一区二区激情短视频 | 国产精品久久久久成人av| 欧美3d第一页| 日韩电影二区| 国产熟女欧美一区二区| 两性夫妻黄色片 | 国产片特级美女逼逼视频| 999精品在线视频| 亚洲图色成人| 国产av一区二区精品久久| 国产精品.久久久| 男女边摸边吃奶| 最新中文字幕久久久久| 国产精品秋霞免费鲁丝片| 日本爱情动作片www.在线观看| 美女福利国产在线| 亚洲丝袜综合中文字幕| 精品国产乱码久久久久久小说| 午夜老司机福利剧场| 亚洲国产看品久久| 精品一区二区免费观看| 秋霞在线观看毛片| 日本免费在线观看一区| 午夜免费鲁丝| 99久久人妻综合| 久久狼人影院| 全区人妻精品视频| 边亲边吃奶的免费视频| 一级毛片 在线播放| 毛片一级片免费看久久久久| 国产无遮挡羞羞视频在线观看| 亚洲av电影在线进入| 午夜久久久在线观看| 久久久久久人人人人人| 亚洲精品久久久久久婷婷小说| av卡一久久| 国产淫语在线视频| 国产精品国产三级国产av玫瑰| 男人爽女人下面视频在线观看| 国产xxxxx性猛交| 国产成人欧美| 成年av动漫网址| 久久婷婷青草| 久久久亚洲精品成人影院| 国产亚洲最大av| 久久精品久久久久久久性| 色5月婷婷丁香| 亚洲av国产av综合av卡| 又黄又粗又硬又大视频| 国产男女超爽视频在线观看| 青春草国产在线视频| 午夜福利乱码中文字幕| 亚洲国产欧美日韩在线播放| 国产免费又黄又爽又色| 亚洲av欧美aⅴ国产| 国产成人免费观看mmmm| 熟女人妻精品中文字幕| 日韩在线高清观看一区二区三区| 制服丝袜香蕉在线| 国产男女内射视频| 99热6这里只有精品| 中国美白少妇内射xxxbb| 一区在线观看完整版| 国产精品久久久久久av不卡| 女人被躁到高潮嗷嗷叫费观| 插逼视频在线观看| 国产男人的电影天堂91| 亚洲欧美清纯卡通| 国产xxxxx性猛交| 人成视频在线观看免费观看| 我的女老师完整版在线观看| 日韩欧美精品免费久久| 精品亚洲乱码少妇综合久久| 成人免费观看视频高清| 国产精品国产三级国产av玫瑰| 热99国产精品久久久久久7| 国产成人精品福利久久| 在线观看国产h片| 男人添女人高潮全过程视频| 各种免费的搞黄视频| 18禁观看日本| 中文欧美无线码| 亚洲国产精品成人久久小说| 在线看a的网站| 91精品伊人久久大香线蕉| 久久亚洲国产成人精品v| 爱豆传媒免费全集在线观看| 国产乱人偷精品视频| 2022亚洲国产成人精品| 51国产日韩欧美| 国产高清不卡午夜福利| 日本爱情动作片www.在线观看| 久久狼人影院| 午夜激情久久久久久久| 国产日韩欧美在线精品| 日韩大片免费观看网站| 久久久精品区二区三区| 在线精品无人区一区二区三| 天天影视国产精品| 天天操日日干夜夜撸| 国产高清国产精品国产三级| 99热这里只有是精品在线观看| 亚洲av在线观看美女高潮| 国产免费现黄频在线看| 少妇人妻久久综合中文| 又黄又粗又硬又大视频| 两个人免费观看高清视频| 日产精品乱码卡一卡2卡三| 久久人人爽av亚洲精品天堂| 伊人久久国产一区二区| 欧美xxⅹ黑人| 男女国产视频网站| 狠狠精品人妻久久久久久综合| 久久精品人人爽人人爽视色| 啦啦啦在线观看免费高清www| 老司机影院成人| av视频免费观看在线观看| 国产精品偷伦视频观看了| videossex国产| 久久国产精品男人的天堂亚洲 | 成人漫画全彩无遮挡| 欧美成人精品欧美一级黄| 亚洲精华国产精华液的使用体验| 丝袜人妻中文字幕| 国精品久久久久久国模美| 国产在线一区二区三区精| 成人毛片60女人毛片免费| 亚洲国产精品一区三区| 丝瓜视频免费看黄片| 高清黄色对白视频在线免费看| 日韩av免费高清视频| 国产精品久久久久久精品古装| 日韩,欧美,国产一区二区三区| 99香蕉大伊视频| 老司机影院成人| 欧美激情 高清一区二区三区| 欧美精品一区二区大全| 卡戴珊不雅视频在线播放| 久久国产精品男人的天堂亚洲 | 亚洲五月色婷婷综合| 99国产综合亚洲精品| 中国国产av一级| 国产爽快片一区二区三区| 美女大奶头黄色视频| 久久精品久久精品一区二区三区| 亚洲伊人色综图| 午夜福利网站1000一区二区三区| 国产视频首页在线观看| 内地一区二区视频在线| 中文字幕另类日韩欧美亚洲嫩草| 九色成人免费人妻av| 亚洲精品中文字幕在线视频| 国产av精品麻豆| 伦理电影免费视频| 九九爱精品视频在线观看| 日本黄大片高清| 最近中文字幕高清免费大全6| 午夜福利视频在线观看免费| 久久99蜜桃精品久久| 最后的刺客免费高清国语| 男人添女人高潮全过程视频| 欧美人与性动交α欧美精品济南到 | 99久久中文字幕三级久久日本| 日日摸夜夜添夜夜爱| av黄色大香蕉| 男女边摸边吃奶| av国产精品久久久久影院| 欧美97在线视频| 视频区图区小说| 欧美xxxx性猛交bbbb| 天天躁夜夜躁狠狠躁躁| 欧美日韩亚洲高清精品| 欧美日韩综合久久久久久| 国产男女内射视频| 午夜日本视频在线| 两个人看的免费小视频| 18禁动态无遮挡网站| 久久精品人人爽人人爽视色| 亚洲国产精品999| 欧美人与性动交α欧美精品济南到 | 日韩 亚洲 欧美在线| 深夜精品福利| 国产精品国产三级国产av玫瑰| 免费黄色在线免费观看| 亚洲经典国产精华液单| 在线观看三级黄色| 精品亚洲成a人片在线观看| 欧美日韩精品成人综合77777| 欧美人与性动交α欧美软件 | 黄色视频在线播放观看不卡| freevideosex欧美| 亚洲精品456在线播放app| 香蕉国产在线看| 999精品在线视频| 中文字幕人妻熟女乱码| 黑人巨大精品欧美一区二区蜜桃 | 熟妇人妻不卡中文字幕| 男女啪啪激烈高潮av片| xxxhd国产人妻xxx| 美女中出高潮动态图| 亚洲欧美成人综合另类久久久| 狂野欧美激情性bbbbbb| 狠狠婷婷综合久久久久久88av| 久久热在线av| 久久狼人影院| 日日撸夜夜添| 欧美xxxx性猛交bbbb| 波野结衣二区三区在线| 精品一区在线观看国产| 亚洲少妇的诱惑av| 免费观看a级毛片全部| 免费黄色在线免费观看| 寂寞人妻少妇视频99o| 日日爽夜夜爽网站| 免费看不卡的av| 午夜激情久久久久久久| 精品人妻一区二区三区麻豆| 观看av在线不卡| 最近的中文字幕免费完整| 波野结衣二区三区在线| 夫妻午夜视频| 一级爰片在线观看| 国产国语露脸激情在线看| 久久精品久久久久久久性| 男女下面插进去视频免费观看 | 黄色一级大片看看| www.熟女人妻精品国产 | 精品国产一区二区久久| 成人二区视频| 亚洲精品日韩在线中文字幕| 又黄又粗又硬又大视频| 成人免费观看视频高清| 欧美日韩视频高清一区二区三区二| 免费少妇av软件| 99热网站在线观看| 婷婷色av中文字幕| 日产精品乱码卡一卡2卡三| 又黄又粗又硬又大视频| 看十八女毛片水多多多| www.熟女人妻精品国产 | 日本wwww免费看| 黄色 视频免费看| 婷婷色麻豆天堂久久| 亚洲欧美清纯卡通| 国产在线视频一区二区| 久久久久精品久久久久真实原创| 日韩人妻精品一区2区三区| 校园人妻丝袜中文字幕| 视频在线观看一区二区三区| 日日摸夜夜添夜夜爱| 久久久精品免费免费高清| 久久久精品免费免费高清| 精品国产乱码久久久久久小说| 国产黄色视频一区二区在线观看| 日本免费在线观看一区| 一区二区三区乱码不卡18| 亚洲成av片中文字幕在线观看 | 欧美xxⅹ黑人| av国产久精品久网站免费入址| 亚洲久久久国产精品| 精品第一国产精品| 欧美老熟妇乱子伦牲交| 伦理电影免费视频| 一区二区日韩欧美中文字幕 | 精品卡一卡二卡四卡免费| 不卡视频在线观看欧美| 狂野欧美激情性xxxx在线观看| 男女无遮挡免费网站观看| av又黄又爽大尺度在线免费看| 亚洲国产欧美日韩在线播放| 亚洲精品久久久久久婷婷小说| 国语对白做爰xxxⅹ性视频网站| 91精品三级在线观看| 18禁裸乳无遮挡动漫免费视频| 草草在线视频免费看| 在线观看www视频免费| 国产精品 国内视频| 2021少妇久久久久久久久久久| 91精品三级在线观看| 搡老乐熟女国产| 精品人妻在线不人妻| 五月玫瑰六月丁香| 亚洲伊人色综图| 欧美日韩精品成人综合77777| 国产精品一区www在线观看| 久久国产精品大桥未久av| 国产亚洲欧美精品永久| 晚上一个人看的免费电影| 久久久久精品久久久久真实原创| 天天躁夜夜躁狠狠躁躁| 日韩伦理黄色片| 内地一区二区视频在线| 精品午夜福利在线看| 另类亚洲欧美激情| 久久国产亚洲av麻豆专区| 国产免费福利视频在线观看| 另类精品久久| 菩萨蛮人人尽说江南好唐韦庄| 国产日韩欧美在线精品| 欧美日韩视频高清一区二区三区二| 久久久久久久久久久免费av| 国产精品一区www在线观看| 91国产中文字幕| av在线app专区| 伦理电影免费视频| 免费高清在线观看日韩| 亚洲欧美日韩另类电影网站| 国产麻豆69| 考比视频在线观看| 午夜福利视频精品| 精品人妻偷拍中文字幕| 免费看av在线观看网站| 国产成人免费观看mmmm| 国产精品不卡视频一区二区| 午夜福利视频精品| 日韩人妻精品一区2区三区| 午夜精品国产一区二区电影| 在线观看三级黄色| 日韩,欧美,国产一区二区三区| 美国免费a级毛片| 男女边摸边吃奶| 韩国精品一区二区三区 | 纯流量卡能插随身wifi吗| 国产精品一国产av| 久久久久久久大尺度免费视频| 蜜臀久久99精品久久宅男| 色婷婷久久久亚洲欧美| 欧美精品一区二区大全| 欧美xxxx性猛交bbbb| 欧美精品人与动牲交sv欧美| 少妇 在线观看| 亚洲精品,欧美精品| 亚洲成人一二三区av| av福利片在线| 精品亚洲乱码少妇综合久久| 七月丁香在线播放| av在线老鸭窝| 爱豆传媒免费全集在线观看| 巨乳人妻的诱惑在线观看| 多毛熟女@视频| a级片在线免费高清观看视频| 97在线视频观看| 80岁老熟妇乱子伦牲交| 狂野欧美激情性xxxx在线观看| 久久毛片免费看一区二区三区| 日韩av免费高清视频| 国产又色又爽无遮挡免| 精品第一国产精品| 亚洲国产日韩一区二区| 国精品久久久久久国模美| 免费高清在线观看日韩| 亚洲av免费高清在线观看| 免费观看av网站的网址| 亚洲国产精品成人久久小说| 丝袜人妻中文字幕| 亚洲精品中文字幕在线视频| 久久精品久久久久久噜噜老黄| 黄色 视频免费看| 草草在线视频免费看| 丝袜喷水一区| 亚洲精品乱久久久久久| 免费人成在线观看视频色| 亚洲av福利一区| 成人午夜精彩视频在线观看| 在线观看国产h片| 亚洲精品美女久久av网站| 黄色毛片三级朝国网站| 色网站视频免费| 国产亚洲精品久久久com| 亚洲精品视频女| 亚洲av综合色区一区| 日韩精品有码人妻一区| 国产深夜福利视频在线观看| 最近最新中文字幕免费大全7| 极品少妇高潮喷水抽搐| 大片电影免费在线观看免费| kizo精华| 91在线精品国自产拍蜜月| 在线精品无人区一区二区三| 国产免费视频播放在线视频| 日本免费在线观看一区| 水蜜桃什么品种好| av在线观看视频网站免费| 黄网站色视频无遮挡免费观看| 两性夫妻黄色片 | 色94色欧美一区二区| 欧美 亚洲 国产 日韩一| 1024视频免费在线观看| 飞空精品影院首页| 亚洲av.av天堂| 日本欧美视频一区| 在线观看国产h片| 少妇高潮的动态图| 精品少妇内射三级| 波野结衣二区三区在线| 成人无遮挡网站| av网站免费在线观看视频| 青春草国产在线视频| 中文字幕人妻熟女乱码| 少妇精品久久久久久久| 伦理电影免费视频| 国产一区二区激情短视频 | 国产国语露脸激情在线看| 久久久a久久爽久久v久久| 国产精品人妻久久久影院| 国产淫语在线视频| 久久综合国产亚洲精品| 国产在线免费精品| 国产成人免费无遮挡视频| 成人亚洲精品一区在线观看| 日韩免费高清中文字幕av| 男女边摸边吃奶| 国产精品蜜桃在线观看| 亚洲综合色惰| 在线观看人妻少妇|