In order to illustrate the combustion characteristics of RP-3 kerosene which is widely used in Chinese aero-engines, the combustion characteristics of RP-3 kerosene were experimentally inves- tigated in a constant vol...In order to illustrate the combustion characteristics of RP-3 kerosene which is widely used in Chinese aero-engines, the combustion characteristics of RP-3 kerosene were experimentally inves- tigated in a constant volume combustion chamber. The experiments were performed at four different pressures of 0.1 MPa, 0.3 MPa, 0.5 MPa and 0.7 MPa, and three different temperatures of 390 K, 420 K and 450 K, and over the equivalence ratio range of 0.6-1.6. Furthermore, the laminar combus- tion speeds of a surrogate fuel for RP-3 kerosene were simulated under certain conditions. The results show that increasing the initial temperature or decreasing the initial pressure causes an increase in the laminar combustion speed of RP-3 kerosene. With the equivalence ratio increasing from 0.6 to 1.6, the laminar combustion speed increases initially and then decreases gradually. The highest laminar combustion speed is measured under fuel rich condition （the equivalence ratio is 1.2）. At the same time, the Markstein length shows the same changing trend as the laminar com- bustion speed with modification of the initial pressure. Increasing the initial pressure will increase the instability of the flame front, which is established by decreased Markstein length. However, different from the effects of the initial temperature and equivalence ratio on the laminar combustion speed, increasing the equivalence ratio will lead to a decrease in the Markstein length and the stability of the flame front, and the effect of the initial temperature on the Markstein length is unclear. Further- more, the simulated laminar combustion speeds of the surrogate fuel agree with the corresponding experimental datas of RP-3 kerosene within ~10% deviation under certain conditions.展开更多
To investigate the characteristics of vaporized RP-3 kerosene combustion in a scramjet combustor enhanced by the micro vortex generator(MVG),a series of experiments are carried out based on the advanced combustion dia...To investigate the characteristics of vaporized RP-3 kerosene combustion in a scramjet combustor enhanced by the micro vortex generator(MVG),a series of experiments are carried out based on the advanced combustion diagnosis technique.The high-enthalpy incoming flow is accelerated to supersonic through a Mach 2.52 nozzle,the total pressure and temperature of which are 1.6 MPa and 1486 K,respectively.The effect of MVG on the ignition process,flame distribution,and combustor pressure along the bottom wall is well revealed,and the effects of the position and number of MVGs on stable combustion performance are analyzed.The results indicate that the development processes of the initial flame kernel with and without an MVG during ignition process show a similar behavior.The installation of an MVG can lift the shear layer,promote the penetration of flame deeper into the mainstream,and expand the area of the reactive region.Reducing the distance between the MVG and the injection position and increasing the number of MVGs are regarded as effective ways of improving the mixing degree of fuel and air with a resultant intensification of chemical reactions and flame luminescence.The effect of mixing and subsequent combustion is enhanced by shortening the distance between the MVG and the injection position.As the layout schemes of the MVG vary,the pressure distribution between the injection position and the leading edge of the cavity changes considerably,while that in the cavity remains almost constant.Increasing the number of MVGs is also beneficial for improving the premixed degree of fuel and incoming flow and results in more violent chemical reactions downstream of the cavity.展开更多
基金financial supports from the National Natural Science Foundation of China(No.51376133 and No.51506132)
文摘In order to illustrate the combustion characteristics of RP-3 kerosene which is widely used in Chinese aero-engines, the combustion characteristics of RP-3 kerosene were experimentally inves- tigated in a constant volume combustion chamber. The experiments were performed at four different pressures of 0.1 MPa, 0.3 MPa, 0.5 MPa and 0.7 MPa, and three different temperatures of 390 K, 420 K and 450 K, and over the equivalence ratio range of 0.6-1.6. Furthermore, the laminar combus- tion speeds of a surrogate fuel for RP-3 kerosene were simulated under certain conditions. The results show that increasing the initial temperature or decreasing the initial pressure causes an increase in the laminar combustion speed of RP-3 kerosene. With the equivalence ratio increasing from 0.6 to 1.6, the laminar combustion speed increases initially and then decreases gradually. The highest laminar combustion speed is measured under fuel rich condition （the equivalence ratio is 1.2）. At the same time, the Markstein length shows the same changing trend as the laminar com- bustion speed with modification of the initial pressure. Increasing the initial pressure will increase the instability of the flame front, which is established by decreased Markstein length. However, different from the effects of the initial temperature and equivalence ratio on the laminar combustion speed, increasing the equivalence ratio will lead to a decrease in the Markstein length and the stability of the flame front, and the effect of the initial temperature on the Markstein length is unclear. Further- more, the simulated laminar combustion speeds of the surrogate fuel agree with the corresponding experimental datas of RP-3 kerosene within ~10% deviation under certain conditions.
基金supported by the National Natural Science Foundation of China(No.12002373)。
文摘To investigate the characteristics of vaporized RP-3 kerosene combustion in a scramjet combustor enhanced by the micro vortex generator(MVG),a series of experiments are carried out based on the advanced combustion diagnosis technique.The high-enthalpy incoming flow is accelerated to supersonic through a Mach 2.52 nozzle,the total pressure and temperature of which are 1.6 MPa and 1486 K,respectively.The effect of MVG on the ignition process,flame distribution,and combustor pressure along the bottom wall is well revealed,and the effects of the position and number of MVGs on stable combustion performance are analyzed.The results indicate that the development processes of the initial flame kernel with and without an MVG during ignition process show a similar behavior.The installation of an MVG can lift the shear layer,promote the penetration of flame deeper into the mainstream,and expand the area of the reactive region.Reducing the distance between the MVG and the injection position and increasing the number of MVGs are regarded as effective ways of improving the mixing degree of fuel and air with a resultant intensification of chemical reactions and flame luminescence.The effect of mixing and subsequent combustion is enhanced by shortening the distance between the MVG and the injection position.As the layout schemes of the MVG vary,the pressure distribution between the injection position and the leading edge of the cavity changes considerably,while that in the cavity remains almost constant.Increasing the number of MVGs is also beneficial for improving the premixed degree of fuel and incoming flow and results in more violent chemical reactions downstream of the cavity.
