In this research combustion of aluminum dust particles in a quiescent medium with spatially discrete sources distributed in a random way was studied by a numerical approach.A new thermal model was generated to estimat...In this research combustion of aluminum dust particles in a quiescent medium with spatially discrete sources distributed in a random way was studied by a numerical approach.A new thermal model was generated to estimate flame propagation speed in a lean/rich reaction medium.Flame speed for different particle diameters and the effects of various oxidizers such as carbon dioxide and oxygen on flame speed were studied.Nitrogen was considered the inert gas.In addition,the quenching distance and the minimum ignition energy(MIE) were studied as a function of dust concentration.Different burning time models for aluminum were employed and their results were compared with each other.The model was based on conduction heat transfer mechanism using the heat point source method.The combustion of single-particle was first studied and the solution was presented.Then the dust combustion was investigated using the superposition principle to include the effects of surrounding particles.It is found that larger particles have higher values of quenching distance in comparison with smaller particles in an assumed dust concentration.With the increase of dust concentration the value of MIE would be decreased for an assumed particle diameter.Considering random discrete heat sources method,the obtained results of random distribution of fuel particles in space provide closer and realistic predictions of the combustion physics of aluminum dust flame as compared with the experimental findings.展开更多
The effect of external vibration on the velocity uniformity of the moving mechanism of the angular mir⁃ror translational Fourier transform interferometer(hereinafter referred to as interferometer)can be quantitatively...The effect of external vibration on the velocity uniformity of the moving mechanism of the angular mir⁃ror translational Fourier transform interferometer(hereinafter referred to as interferometer)can be quantitatively analysed by the interferometer optical range difference velocity stability.The article proposes a more comprehen⁃sive method of analysing the optical range difference velocity uniformity for the reliability of the interferometer ki⁃nematic mechanism under the influence of on-orbit microvibration in the process of space spectroscopy detection.The method incorporates the structural response of the interferometer caused by external excitation into the stabili⁃ty analysis as one of the influencing factors,so as to reflect the reliability of the interferometer in orbit more realis⁃tically,and judge the microvibration criticality that the interferometer can withstand more accurately.At the same time,an optical surface model of the interferometer is established to further theoretically characterise the effect of microvibration on the homogeneity of the interferometric mechanism.The method discussed in the article pro⁃vides a way of thinking for the judgement of the reliability of the mechanism movement under the external excita⁃tion perturbation as well as the research on the optimisation of the mechanism control.展开更多
文摘In this research combustion of aluminum dust particles in a quiescent medium with spatially discrete sources distributed in a random way was studied by a numerical approach.A new thermal model was generated to estimate flame propagation speed in a lean/rich reaction medium.Flame speed for different particle diameters and the effects of various oxidizers such as carbon dioxide and oxygen on flame speed were studied.Nitrogen was considered the inert gas.In addition,the quenching distance and the minimum ignition energy(MIE) were studied as a function of dust concentration.Different burning time models for aluminum were employed and their results were compared with each other.The model was based on conduction heat transfer mechanism using the heat point source method.The combustion of single-particle was first studied and the solution was presented.Then the dust combustion was investigated using the superposition principle to include the effects of surrounding particles.It is found that larger particles have higher values of quenching distance in comparison with smaller particles in an assumed dust concentration.With the increase of dust concentration the value of MIE would be decreased for an assumed particle diameter.Considering random discrete heat sources method,the obtained results of random distribution of fuel particles in space provide closer and realistic predictions of the combustion physics of aluminum dust flame as compared with the experimental findings.
文摘The effect of external vibration on the velocity uniformity of the moving mechanism of the angular mir⁃ror translational Fourier transform interferometer(hereinafter referred to as interferometer)can be quantitatively analysed by the interferometer optical range difference velocity stability.The article proposes a more comprehen⁃sive method of analysing the optical range difference velocity uniformity for the reliability of the interferometer ki⁃nematic mechanism under the influence of on-orbit microvibration in the process of space spectroscopy detection.The method incorporates the structural response of the interferometer caused by external excitation into the stabili⁃ty analysis as one of the influencing factors,so as to reflect the reliability of the interferometer in orbit more realis⁃tically,and judge the microvibration criticality that the interferometer can withstand more accurately.At the same time,an optical surface model of the interferometer is established to further theoretically characterise the effect of microvibration on the homogeneity of the interferometric mechanism.The method discussed in the article pro⁃vides a way of thinking for the judgement of the reliability of the mechanism movement under the external excita⁃tion perturbation as well as the research on the optimisation of the mechanism control.
