The performance of combustion driver ignited by multi-spark plugs distributed along axial direction has been analysed and tested. An improved ignition method with three circumferential equidistributed ignitors at main...The performance of combustion driver ignited by multi-spark plugs distributed along axial direction has been analysed and tested. An improved ignition method with three circumferential equidistributed ignitors at main diaphragm has been presented, by which the produced incident shock waves have higher repeatability, and better steadiness in the pressure, temperature and velocity fields of flow behind the incidence shock, and thus meets the requirements of aerodynamic experiment. The attachment of a damping section at the end of the driver can eliminate the high reflection pressure produced by detonation wave, and the backward detonation driver can be employed to generate high enthalpy and high density test flow. The incident shock wave produced by this method is well repeated and with weak attenuation. The reflection wave caused by the contracted section at the main diaphragm will weaken the unfavorable effect of rarefaction wave behind the detonation wave, which indicates that the forward detonation driver can be applied in the practice. For incident shock wave of identical strength, the initial pressure of the forward detonation driver is about 1 order of magnitude lower than that of backward detonation.展开更多
ARecent progress on detonation drivers is reviewed. Performances of the forward detonation driver and backward detonation driver have been observed. To eliminate occurrence of a Taylor wave following the detonation wa...ARecent progress on detonation drivers is reviewed. Performances of the forward detonation driver and backward detonation driver have been observed. To eliminate occurrence of a Taylor wave following the detonation wave in the primary driver and to improve the performance of the detonation driver, an additional backward detonation driver was proposed to attach to the end of the forward detonation driver. When the ratio of the initial pressures between the additional and the primary drivers becomes larger than or equal to a critical value, the Taylor wave will disappear, and thus a homogeneous driving gas with high pressure and high temperature can be generated. Furthermore, an over-driving detonation wave will be also obtained, which can increase the driving capability.展开更多
The hypersonic flow at orbital speeds is a fundamental issue for the ground tests of aerospace crafts.The detonation-driven high-enthalpy expansion tube(JF16 expansion tube)was developed to investigate re-entry physic...The hypersonic flow at orbital speeds is a fundamental issue for the ground tests of aerospace crafts.The detonation-driven high-enthalpy expansion tube(JF16 expansion tube)was developed to investigate re-entry physics.A forward detonation cavity(FDC)driver was applied in the JF16 expansion tube to create stable driving flows.The sound speed ratio of the detonated to test gas was examined to minimize the magnitude of test flow perturbations.The acceleration section length,incident shock decay and diaphragms thickness were investigated in detail to obtain optimal operation parameters.Flow visualization was also carried out with schlieren system to demonstrate the test flow stability and the effective test duration.Experimental data showed that the test flow with a velocity of 8.3 km/s and a total enthalpy up to 40 MJ/kg can be generated successfully and the test duration lasts for more than 50μs.展开更多
目前以碳氢燃料与空气可爆混合物的直管爆震室存在较长的爆燃向爆震转变(Deflagration to Detonation Transition,简称'DDT')距离,从而导致发动机整机长度过长等问题。为解决此问题,采用8种螺旋构型的爆震管替代现有国内外普遍...目前以碳氢燃料与空气可爆混合物的直管爆震室存在较长的爆燃向爆震转变(Deflagration to Detonation Transition,简称'DDT')距离,从而导致发动机整机长度过长等问题。为解决此问题,采用8种螺旋构型的爆震管替代现有国内外普遍研究的直管构型的爆震管进行了一系列实验。首先对不同螺旋结构的爆震管进行冷态流阻特性实验,得出了螺旋结构参数和流阻的关系;再结合冷态实验结果,选取4种螺旋结构进行了热态爆震实验。实验结果表明,所有螺旋结构均可获得充分发展的爆震波;螺旋爆震管缓燃向爆震转变时间随螺旋中轴线曲率半径增加而减小;相对于长2.0m的直管爆震管,螺旋爆震管DDT时间缩短了0.415～0.589ms,DDT距离沿螺旋线方向缩短了0.35m,爆震管轴向长度缩短了0.78～1.28m。展开更多
基金State Science and Technology CommitteeNational Natural Foundation of Science of China (19082012)+1 种基金 Chinese Academy of SciencesProject of National High Technology of China.
文摘The performance of combustion driver ignited by multi-spark plugs distributed along axial direction has been analysed and tested. An improved ignition method with three circumferential equidistributed ignitors at main diaphragm has been presented, by which the produced incident shock waves have higher repeatability, and better steadiness in the pressure, temperature and velocity fields of flow behind the incidence shock, and thus meets the requirements of aerodynamic experiment. The attachment of a damping section at the end of the driver can eliminate the high reflection pressure produced by detonation wave, and the backward detonation driver can be employed to generate high enthalpy and high density test flow. The incident shock wave produced by this method is well repeated and with weak attenuation. The reflection wave caused by the contracted section at the main diaphragm will weaken the unfavorable effect of rarefaction wave behind the detonation wave, which indicates that the forward detonation driver can be applied in the practice. For incident shock wave of identical strength, the initial pressure of the forward detonation driver is about 1 order of magnitude lower than that of backward detonation.
基金This work was supported by the National Natural Science Foundation of China (Grant No.10082004).
文摘ARecent progress on detonation drivers is reviewed. Performances of the forward detonation driver and backward detonation driver have been observed. To eliminate occurrence of a Taylor wave following the detonation wave in the primary driver and to improve the performance of the detonation driver, an additional backward detonation driver was proposed to attach to the end of the forward detonation driver. When the ratio of the initial pressures between the additional and the primary drivers becomes larger than or equal to a critical value, the Taylor wave will disappear, and thus a homogeneous driving gas with high pressure and high temperature can be generated. Furthermore, an over-driving detonation wave will be also obtained, which can increase the driving capability.
基金The National Natural Science Foundation of China (Grant Nos. 10632090 and 10621202)
文摘The hypersonic flow at orbital speeds is a fundamental issue for the ground tests of aerospace crafts.The detonation-driven high-enthalpy expansion tube(JF16 expansion tube)was developed to investigate re-entry physics.A forward detonation cavity(FDC)driver was applied in the JF16 expansion tube to create stable driving flows.The sound speed ratio of the detonated to test gas was examined to minimize the magnitude of test flow perturbations.The acceleration section length,incident shock decay and diaphragms thickness were investigated in detail to obtain optimal operation parameters.Flow visualization was also carried out with schlieren system to demonstrate the test flow stability and the effective test duration.Experimental data showed that the test flow with a velocity of 8.3 km/s and a total enthalpy up to 40 MJ/kg can be generated successfully and the test duration lasts for more than 50μs.
文摘目前以碳氢燃料与空气可爆混合物的直管爆震室存在较长的爆燃向爆震转变(Deflagration to Detonation Transition,简称'DDT')距离,从而导致发动机整机长度过长等问题。为解决此问题,采用8种螺旋构型的爆震管替代现有国内外普遍研究的直管构型的爆震管进行了一系列实验。首先对不同螺旋结构的爆震管进行冷态流阻特性实验,得出了螺旋结构参数和流阻的关系;再结合冷态实验结果,选取4种螺旋结构进行了热态爆震实验。实验结果表明,所有螺旋结构均可获得充分发展的爆震波;螺旋爆震管缓燃向爆震转变时间随螺旋中轴线曲率半径增加而减小;相对于长2.0m的直管爆震管,螺旋爆震管DDT时间缩短了0.415～0.589ms,DDT距离沿螺旋线方向缩短了0.35m,爆震管轴向长度缩短了0.78～1.28m。
