In order to study the instability propagation characteristics of the liquid kerosene rotating detonation wave(RDW),a series of experimental tests were carried out on the rotating detonation combustor(RDC)with air-heat...In order to study the instability propagation characteristics of the liquid kerosene rotating detonation wave(RDW),a series of experimental tests were carried out on the rotating detonation combustor(RDC)with air-heater.The fuel and oxidizer are room-temperature liquid kerosene and preheated oxygenenriched air,respectively.The experimental tests keep the equivalence ratio of 0.81 and the oxygen mass fraction of 35%unchanged,and the total mass flow rate is maintained at about 1000 g/s,changing the total temperature of the oxygen-enriched air from 620 K to 860 K.Three different types of instability were observed in the experiments:temporal and spatial instability,mode transition and re-initiation.The interaction between RDW and supply plenum may be the main reason for the fluctuations of detonation wave velocity and pressure peaks with time.Moreover,the inconsistent mixing of fuel and oxidizer at different circumferential positions is related to RDW oscillate spatially.The phenomenon of single-double-single wave transition is analyzed.During the transition,the initial RDW weakens until disappears,and the compression wave strengthens until it becomes a new RDWand propagates steadily.The increased deflagration between the detonation products and the fresh gas layer caused by excessively high temperature is one of the reasons for the RDC quenching and re-initiation.展开更多
In the process of 2-D compressional wave propagation in a rock mass with multiple parallel joints along the radian direction normal to the joints, the maximum possible wave amplitude corresponding to the points betwee...In the process of 2-D compressional wave propagation in a rock mass with multiple parallel joints along the radian direction normal to the joints, the maximum possible wave amplitude corresponding to the points between the two adjacent joints in the joint set is controlled by superposition of the multiple transmitted and the reflected waves, measured by the maximum rebound ratio. Parametric studies on the maximum rebound ratio along the radian direction normal to the joints were performed in universal distinct element code. The results show that the maximum rebound ratio is influenced by three factors, i.e., the normalized normal stiffness of joints, the ratio of joint spacing to wavelength and the joint from which the wave rebounds. The relationship between the maximum rebound ratio and the influence factors is generalized into five charts. Those charts can be used as the prediction model for estimating the maximum rebound ratio.展开更多
利用偶极横波声波成像(Dipole Shear Sonic Imager,DSI)测井资料计算了纵、横波衰减和纵、横波品质因子QP和QS.对纵、横波在碳酸盐岩含气层和非含气层中的衰减特征研究表明,碳酸盐岩含气层中的纵波衰减比非含气层中的纵波衰减强;横波衰...利用偶极横波声波成像(Dipole Shear Sonic Imager,DSI)测井资料计算了纵、横波衰减和纵、横波品质因子QP和QS.对纵、横波在碳酸盐岩含气层和非含气层中的衰减特征研究表明,碳酸盐岩含气层中的纵波衰减比非含气层中的纵波衰减强;横波衰减和横波品质因子在碳酸盐岩含气层和非含气层中的变化不大。根据DSI测井资料计算出的纵、横波衰减和纵、横波品质因子在碳酸盐岩含气层和非含气层中的这些差异,给出了一种利用纵、横波品质因子比值QP/QS识别碳酸盐岩含气层的方法。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11802137,11702143 and 11802039)the Fundamental Research Funds for the Central Universities(No.30919011259).
文摘In order to study the instability propagation characteristics of the liquid kerosene rotating detonation wave(RDW),a series of experimental tests were carried out on the rotating detonation combustor(RDC)with air-heater.The fuel and oxidizer are room-temperature liquid kerosene and preheated oxygenenriched air,respectively.The experimental tests keep the equivalence ratio of 0.81 and the oxygen mass fraction of 35%unchanged,and the total mass flow rate is maintained at about 1000 g/s,changing the total temperature of the oxygen-enriched air from 620 K to 860 K.Three different types of instability were observed in the experiments:temporal and spatial instability,mode transition and re-initiation.The interaction between RDW and supply plenum may be the main reason for the fluctuations of detonation wave velocity and pressure peaks with time.Moreover,the inconsistent mixing of fuel and oxidizer at different circumferential positions is related to RDW oscillate spatially.The phenomenon of single-double-single wave transition is analyzed.During the transition,the initial RDW weakens until disappears,and the compression wave strengthens until it becomes a new RDWand propagates steadily.The increased deflagration between the detonation products and the fresh gas layer caused by excessively high temperature is one of the reasons for the RDC quenching and re-initiation.
基金Projects(50278057) supported by the National Natural Science Foundation of China project(2002CB412703) supported by Major State Basic Research Development Program of China
文摘In the process of 2-D compressional wave propagation in a rock mass with multiple parallel joints along the radian direction normal to the joints, the maximum possible wave amplitude corresponding to the points between the two adjacent joints in the joint set is controlled by superposition of the multiple transmitted and the reflected waves, measured by the maximum rebound ratio. Parametric studies on the maximum rebound ratio along the radian direction normal to the joints were performed in universal distinct element code. The results show that the maximum rebound ratio is influenced by three factors, i.e., the normalized normal stiffness of joints, the ratio of joint spacing to wavelength and the joint from which the wave rebounds. The relationship between the maximum rebound ratio and the influence factors is generalized into five charts. Those charts can be used as the prediction model for estimating the maximum rebound ratio.
文摘利用偶极横波声波成像(Dipole Shear Sonic Imager,DSI)测井资料计算了纵、横波衰减和纵、横波品质因子QP和QS.对纵、横波在碳酸盐岩含气层和非含气层中的衰减特征研究表明,碳酸盐岩含气层中的纵波衰减比非含气层中的纵波衰减强;横波衰减和横波品质因子在碳酸盐岩含气层和非含气层中的变化不大。根据DSI测井资料计算出的纵、横波衰减和纵、横波品质因子在碳酸盐岩含气层和非含气层中的这些差异,给出了一种利用纵、横波品质因子比值QP/QS识别碳酸盐岩含气层的方法。
