This is a numerical study of a falling droplet surrounding by air under the electric field modeled with finite volume method by means of CFD.The VOF method has been employed to model the two-phase flow of the present ...This is a numerical study of a falling droplet surrounding by air under the electric field modeled with finite volume method by means of CFD.The VOF method has been employed to model the two-phase flow of the present study.Various capillary numbers are investigated to analyze the effects of electric field intensity on the falling droplet deformation.Also,the effects of electric potential on the heat transfer coefficient have been examined.The obtained results showed that by applying the electric field at a capillary number of 0.2 the droplet tends to retain its primitive shape as time goes by,with a subtle deformation to an oblate form.Intensifying the electric field to a capillary number of 0.8 droplet deformation is almost insignificantwith time progressing;however,further enhancement in capillary number to 2 causes the droplet to deform as a prolate shape and higher values of this number intensify the prolate form deformation of the droplet and result in pinch-off phenomenon.Ultimately,it is showed that as the electric potential augments the heat transfer coefficient increases in which for electric potential values higher than 2400 V the heat transfer coefficient enhances significantly.展开更多
In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball ...In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball method are used as the rapid detection methods of polymer dissolution. The results show that the error of conductivity method is the largest, and that of dissolution time method is the second, and both methods are time-consuming. Solution viscosity method and insolubles filtration method have small error, but they are time-consuming, especially for offshore platforms, which makes detection inconvenient. The drop ball method is simple in operation and has a small error, so it is a promising method for rapid determination of polymer dissolution time.展开更多
文摘This is a numerical study of a falling droplet surrounding by air under the electric field modeled with finite volume method by means of CFD.The VOF method has been employed to model the two-phase flow of the present study.Various capillary numbers are investigated to analyze the effects of electric field intensity on the falling droplet deformation.Also,the effects of electric potential on the heat transfer coefficient have been examined.The obtained results showed that by applying the electric field at a capillary number of 0.2 the droplet tends to retain its primitive shape as time goes by,with a subtle deformation to an oblate form.Intensifying the electric field to a capillary number of 0.8 droplet deformation is almost insignificantwith time progressing;however,further enhancement in capillary number to 2 causes the droplet to deform as a prolate shape and higher values of this number intensify the prolate form deformation of the droplet and result in pinch-off phenomenon.Ultimately,it is showed that as the electric potential augments the heat transfer coefficient increases in which for electric potential values higher than 2400 V the heat transfer coefficient enhances significantly.
文摘In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball method are used as the rapid detection methods of polymer dissolution. The results show that the error of conductivity method is the largest, and that of dissolution time method is the second, and both methods are time-consuming. Solution viscosity method and insolubles filtration method have small error, but they are time-consuming, especially for offshore platforms, which makes detection inconvenient. The drop ball method is simple in operation and has a small error, so it is a promising method for rapid determination of polymer dissolution time.
