The centrifugal air compressor outlet pipeline vibration was not decreased after barrel viscous dampers were installed in a petrochemical plant in Tianjin.A pipeline-damper experiment apparatus was built for studying ...The centrifugal air compressor outlet pipeline vibration was not decreased after barrel viscous dampers were installed in a petrochemical plant in Tianjin.A pipeline-damper experiment apparatus was built for studying the influence factors of the barrel viscous damper and pipe hoop in pipeline vibration reduction.The performance of the damper under different frequency and amplitude was researched respectively,the results showed that damping effect dependsed mainly on frequency and was not related to amplitude.Damper will fail when its vibration frequency exceeds its limit working frequency which was 40 Hz in test.The mechanical properties and energy dissipation were analyzed by using the Maxwell model,which explains experimental results well.According to damping effect and calculation of stiffness with ANSYS in different hoop width,hoop stiffness should match pipe stiffness and keep uniform along transfer path.Damping effect will get worse when local stiffness is too small or too large.Finally,the outlet pipeline vibration was decreased by 70%after using appropriate pipe hoop width and replacing the original damping liquid.展开更多
Based on the Burgers equation and Manley-Rowe equation, the derivation about nonlinear interaction of the acoustic waves has been done in this paper. After nonlinear interaction among the low-frequency weak waves and ...Based on the Burgers equation and Manley-Rowe equation, the derivation about nonlinear interaction of the acoustic waves has been done in this paper. After nonlinear interaction among the low-frequency weak waves and the pump wave, the analytical solutions of acoustic waves＇ amplitude in the field are deduced. The relationship between normalized energy of high-frequency and the change of acoustic energy before and after the nonlinear interaction of the acoustic waves is analyzed. The experimental results about the changes of the acoustic energy are presented. The study shows that new frequencies are generated and the energies of the low-frequency are modulated in a long term by the pump waves, which leads the energies of the low-frequency acoustic waves to change in the pulse trend in the process of the nonlinear interaction of the acoustic waves. The increase and decrease of the energies of the low-frequency are observed under certain typical conditions, which lays a foundation for practical engineering applications.展开更多
The influence of static electric and magnetic fields on chemical reactions has been studied for many years. It has been known in spectrum analyses that materials absorb microwave energy resonantly, which shows the eff...The influence of static electric and magnetic fields on chemical reactions has been studied for many years. It has been known in spectrum analyses that materials absorb microwave energy resonantly, which shows the effect of microwave on the energy level of molecules. Now the effect of radio-frequency waves, especially microwaves, on chemical reactions is attracting scientists’ attention. A lot of experiments show that microwaves展开更多
基金Supported by the National Basic Research Program of China(No.2012CB026000)the Beijing Education Commission Special Fund andDoctoral Degree Fund(No.20110010110009)
文摘The centrifugal air compressor outlet pipeline vibration was not decreased after barrel viscous dampers were installed in a petrochemical plant in Tianjin.A pipeline-damper experiment apparatus was built for studying the influence factors of the barrel viscous damper and pipe hoop in pipeline vibration reduction.The performance of the damper under different frequency and amplitude was researched respectively,the results showed that damping effect dependsed mainly on frequency and was not related to amplitude.Damper will fail when its vibration frequency exceeds its limit working frequency which was 40 Hz in test.The mechanical properties and energy dissipation were analyzed by using the Maxwell model,which explains experimental results well.According to damping effect and calculation of stiffness with ANSYS in different hoop width,hoop stiffness should match pipe stiffness and keep uniform along transfer path.Damping effect will get worse when local stiffness is too small or too large.Finally,the outlet pipeline vibration was decreased by 70%after using appropriate pipe hoop width and replacing the original damping liquid.
基金financially supported by the Scientific Research Fund of Heilongjiang Provincial Education Department(Grant No.12541132)the Natural Science Youth Foundation of Heilongjiang Province of China(Grant No.QC2015082)
文摘Based on the Burgers equation and Manley-Rowe equation, the derivation about nonlinear interaction of the acoustic waves has been done in this paper. After nonlinear interaction among the low-frequency weak waves and the pump wave, the analytical solutions of acoustic waves＇ amplitude in the field are deduced. The relationship between normalized energy of high-frequency and the change of acoustic energy before and after the nonlinear interaction of the acoustic waves is analyzed. The experimental results about the changes of the acoustic energy are presented. The study shows that new frequencies are generated and the energies of the low-frequency are modulated in a long term by the pump waves, which leads the energies of the low-frequency acoustic waves to change in the pulse trend in the process of the nonlinear interaction of the acoustic waves. The increase and decrease of the energies of the low-frequency are observed under certain typical conditions, which lays a foundation for practical engineering applications.
基金Project supported by the National Natural Science Foundation of China.
文摘The influence of static electric and magnetic fields on chemical reactions has been studied for many years. It has been known in spectrum analyses that materials absorb microwave energy resonantly, which shows the effect of microwave on the energy level of molecules. Now the effect of radio-frequency waves, especially microwaves, on chemical reactions is attracting scientists’ attention. A lot of experiments show that microwaves
