In order to study the settling mechanism of particles in an air-solid magnetically stabilized fluidized bed(MSFB) for separation,we carried out free settling and quasi-zero settling tests on the tracing particles.The ...In order to study the settling mechanism of particles in an air-solid magnetically stabilized fluidized bed(MSFB) for separation,we carried out free settling and quasi-zero settling tests on the tracing particles.The results show that the main resistance forces as the tracing particles settled in an air-solid MSFB were motion resistance force and yield force.The motion resistance and yield forces greatly hindered the free settling of the particles by greatly decreasing the acceleration for settling process of the particles.The acceleration decreased from 3022.62 cm/s 2 to zero in 0.1 s,and in the end,the particles stopped in the air-solid MSFB.The yield force on particles increased with increasing the magnetic field intensity,resulting in decrease of the quasi-zero settling displacement.However,the yield force on particles decreased with increasing the fluidized air velocity,leading to increase of the quasi-zero settling displacement.When the structure and operating parameters of the air-solid MSFB were set up,the yield stress on particles stopped in an air-solid MSFB was a function of diameter and density of particles.The settling displacements of equal diameter particles increased with increasing their densities,and the settling displacements of equal density particles increased with increasing their diameters.展开更多
Applying the integral transform to the coupled problem of thermoelastic and heat conduction equations, the integral representation of the normal displacement field for the air-solid interface waves excited by a pulsed...Applying the integral transform to the coupled problem of thermoelastic and heat conduction equations, the integral representation of the normal displacement field for the air-solid interface waves excited by a pulsed laser line source is obtained. The pole residues of the integrand are performed analytically, and the transient displacement field is calculated by using FFT technique. The thermoelastic excitation and detection of the air-solid interface waves is carried out by a laser ultrasonic system, on which the pulsed laser is focused into a line source onto the interface to excite the air-solid interface waves: leaky Rayleigh wave and Scholte wave, and the interface waves displacement signal is detected successfully by a SH130 laser heterodyne interferometer. The theoretic and experimental results are in good agreement.展开更多
Based on the thermoelastic mechanism of laser ultrasonic, the problems of the thermal conduction and the coupling between the motion of solid and fluid are solved by using the finite element method. And then the trans...Based on the thermoelastic mechanism of laser ultrasonic, the problems of the thermal conduction and the coupling between the motion of solid and fluid are solved by using the finite element method. And then the transient waveforms of leaky Lamb waves induced by pulse laser action on the air-aluminum interface are obtained. Experimental signals of laser-induced leaky Lamb waves at the air-alu- minum interface are detected by applying an our-developed detector, based on the light deflection principle. The dispersion and attenuation properties of leaky Lamb waves are analyzed through the phase spectral analysis.展开更多
The measurements of the mean streamwise and radial velocities,the associated turbulence and the relative particle densities were made in an air-solid two-phase flow in a square sectioned (30mm×30mm)90°vertic...The measurements of the mean streamwise and radial velocities,the associated turbulence and the relative particle densities were made in an air-solid two-phase flow in a square sectioned (30mm×30mm)90°vertical to horizontal bend using laser Doppler velocimetry.The radius ratio of the bend was 2.0.Glass beads of 100μm in diameter were employed to form the solid phase.The measurements of air and solid phases were performed separately at the same bulk velocity 19.34m/s,corresponding to a Reynolds number of 3.87×10~4.The mass ratio of solid to air was 1.6%.The results indicate that the particle trajectories are very close to straight lines. The streamwise velocity profiles for the gas and the solids cross over near the outer wall with the solids having the higher speed.At θ=30°and 45°,particle-wall collisions happen mostly in the region from θ=30°to θ=75°,and cause a sudden change in solid velocity.The particles tend to move towards the outer wall in 90° bend.The particle concentration near the outer wall is much higher than that near the inner wall in the bend, and there are few particles in the inside of the bend.The bend leads to apparent phase separation:atθ=45°, the solids concentrate in the half of the duct near the outer wall.Afterθ=60°the second peak concentration appears,and goes gradually towards the inner wall.展开更多
近年来,胺功能化固体吸附剂在直接空气捕集(Direct Air Capture,DAC)二氧化碳领域受到广泛关注。然而,传统载体(如SBA-15等)的胺功能化会导致吸附剂的孔体积和比表面积减小,在DAC应用中,由于CO_(2)体积分数较低(400×10^(-6)),会进...近年来,胺功能化固体吸附剂在直接空气捕集(Direct Air Capture,DAC)二氧化碳领域受到广泛关注。然而,传统载体(如SBA-15等)的胺功能化会导致吸附剂的孔体积和比表面积减小,在DAC应用中,由于CO_(2)体积分数较低(400×10^(-6)),会进一步降低CO_(2)吸附动力,进而影响吸附剂CO_(2)吸附容量。为解决这一问题,以酚醛树脂微球为模板,通过调控正硅酸乙酯(TEOS)质量分数、引入扩孔剂等方法,制备出高比表面积、大孔容的中空二氧化硅球(RHMS-4)。然后采用浸渍法将四乙烯五胺(TEPA)负载到中空二氧化硅载体上实现其胺功能化。采用XRD、FT-IR等表征手段,探究了RHMS-4-TEPA系列吸附剂结构与性能的构效关系;同时考察了胺负载量、吸附温度以及含水气氛等条件对吸附剂CO_(2)吸附性能的影响。结果显示:在干燥,50℃,CO_(2)体积分数为400×10^(-6)条件下,RHMS-4-TEPA70的CO_(2)吸附量为2.400 mmol/g,而在含水气氛下,RHMS-4-TEPA_(70)的CO_(2)吸附量较干燥气氛下提升约42%。经过10次吸附-解吸循环后,RHMS-4-TEPA_(70)吸附剂仍具有较高的CO_(2)吸附容量和良好的循环稳定性。展开更多
基金supported by the National Natural Science Foundation of China (Nos. 51134022 and 51174203)the Key Project of Chinese National Programs for Fundamental Research and Development (No. 2012CB214904)+2 种基金the National Natural Science Foundation of China for Innovative Research Group (No. 50921002)the Natural Science Foundation of Jiangsu Province (No. BK2010002)the Fundamental Research Funds for the Central Universities (Nos. 2010QNB11 and 2010ZDP01A06)
文摘In order to study the settling mechanism of particles in an air-solid magnetically stabilized fluidized bed(MSFB) for separation,we carried out free settling and quasi-zero settling tests on the tracing particles.The results show that the main resistance forces as the tracing particles settled in an air-solid MSFB were motion resistance force and yield force.The motion resistance and yield forces greatly hindered the free settling of the particles by greatly decreasing the acceleration for settling process of the particles.The acceleration decreased from 3022.62 cm/s 2 to zero in 0.1 s,and in the end,the particles stopped in the air-solid MSFB.The yield force on particles increased with increasing the magnetic field intensity,resulting in decrease of the quasi-zero settling displacement.However,the yield force on particles decreased with increasing the fluidized air velocity,leading to increase of the quasi-zero settling displacement.When the structure and operating parameters of the air-solid MSFB were set up,the yield stress on particles stopped in an air-solid MSFB was a function of diameter and density of particles.The settling displacements of equal diameter particles increased with increasing their densities,and the settling displacements of equal density particles increased with increasing their diameters.
基金supported by the National Natural Science Foundation of China(Grant Nos.10174052,10134020)PRA MX00-2.
文摘Applying the integral transform to the coupled problem of thermoelastic and heat conduction equations, the integral representation of the normal displacement field for the air-solid interface waves excited by a pulsed laser line source is obtained. The pole residues of the integrand are performed analytically, and the transient displacement field is calculated by using FFT technique. The thermoelastic excitation and detection of the air-solid interface waves is carried out by a laser ultrasonic system, on which the pulsed laser is focused into a line source onto the interface to excite the air-solid interface waves: leaky Rayleigh wave and Scholte wave, and the interface waves displacement signal is detected successfully by a SH130 laser heterodyne interferometer. The theoretic and experimental results are in good agreement.
文摘Based on the thermoelastic mechanism of laser ultrasonic, the problems of the thermal conduction and the coupling between the motion of solid and fluid are solved by using the finite element method. And then the transient waveforms of leaky Lamb waves induced by pulse laser action on the air-aluminum interface are obtained. Experimental signals of laser-induced leaky Lamb waves at the air-alu- minum interface are detected by applying an our-developed detector, based on the light deflection principle. The dispersion and attenuation properties of leaky Lamb waves are analyzed through the phase spectral analysis.
文摘The measurements of the mean streamwise and radial velocities,the associated turbulence and the relative particle densities were made in an air-solid two-phase flow in a square sectioned (30mm×30mm)90°vertical to horizontal bend using laser Doppler velocimetry.The radius ratio of the bend was 2.0.Glass beads of 100μm in diameter were employed to form the solid phase.The measurements of air and solid phases were performed separately at the same bulk velocity 19.34m/s,corresponding to a Reynolds number of 3.87×10~4.The mass ratio of solid to air was 1.6%.The results indicate that the particle trajectories are very close to straight lines. The streamwise velocity profiles for the gas and the solids cross over near the outer wall with the solids having the higher speed.At θ=30°and 45°,particle-wall collisions happen mostly in the region from θ=30°to θ=75°,and cause a sudden change in solid velocity.The particles tend to move towards the outer wall in 90° bend.The particle concentration near the outer wall is much higher than that near the inner wall in the bend, and there are few particles in the inside of the bend.The bend leads to apparent phase separation:atθ=45°, the solids concentrate in the half of the duct near the outer wall.Afterθ=60°the second peak concentration appears,and goes gradually towards the inner wall.
文摘近年来,胺功能化固体吸附剂在直接空气捕集(Direct Air Capture,DAC)二氧化碳领域受到广泛关注。然而,传统载体(如SBA-15等)的胺功能化会导致吸附剂的孔体积和比表面积减小,在DAC应用中,由于CO_(2)体积分数较低(400×10^(-6)),会进一步降低CO_(2)吸附动力,进而影响吸附剂CO_(2)吸附容量。为解决这一问题,以酚醛树脂微球为模板,通过调控正硅酸乙酯(TEOS)质量分数、引入扩孔剂等方法,制备出高比表面积、大孔容的中空二氧化硅球(RHMS-4)。然后采用浸渍法将四乙烯五胺(TEPA)负载到中空二氧化硅载体上实现其胺功能化。采用XRD、FT-IR等表征手段,探究了RHMS-4-TEPA系列吸附剂结构与性能的构效关系;同时考察了胺负载量、吸附温度以及含水气氛等条件对吸附剂CO_(2)吸附性能的影响。结果显示:在干燥,50℃,CO_(2)体积分数为400×10^(-6)条件下,RHMS-4-TEPA70的CO_(2)吸附量为2.400 mmol/g,而在含水气氛下,RHMS-4-TEPA_(70)的CO_(2)吸附量较干燥气氛下提升约42%。经过10次吸附-解吸循环后,RHMS-4-TEPA_(70)吸附剂仍具有较高的CO_(2)吸附容量和良好的循环稳定性。
