Electromagnetic forming （EMF） is a high velocity forming process that uses impulse magnetic force. Coil is an important component of EMF system which needs to be designed depending on application. Flat spiral coils ...Electromagnetic forming （EMF） is a high velocity forming process that uses impulse magnetic force. Coil is an important component of EMF system which needs to be designed depending on application. Flat spiral coils are generally used for electromagnetic forming of sheet metals. However, with this type of coil the central portion of the workpiece experiences marginal magnetic force. This leads to in-sufficient deformation at this portion and other problems like air entrapment. In this study, a conceptual design of flat coil was proposed for better distribution of magnetic forces over the workpiece. Comparative analysis of distribution of magnetic force, magnetic field and current density using the proposed and the existing coil designs were carried out using FEM. The result indicates that the proposed coil design produces comparatively better magnetic force distribution over the workpiece. Calculation of self-inductance of such coils was also carried out and was compared with FE simulation.展开更多
The numeric al simulation study on the temperature distribution of underground field for the ground coupled heat pump (GCHP) with vertical spira l coil was carried out by using finite element. The distribution and rec...The numeric al simulation study on the temperature distribution of underground field for the ground coupled heat pump (GCHP) with vertical spira l coil was carried out by using finite element. The distribution and recovery of undergroun d field temperature under different operation ratio and the optimal operation ratio were simulated.The performance parameters, i.e. inlet and outlet temperature of the ground spiral coil in heating and cooling modes were tested, the heat extracted or emitted by the heat pump to the ground was calculated, and the coefficients of performance (COP) of GCHP at heat ing and cooling modes were analyzed.展开更多
This paper gives the strict solution of optical field equation in the optical waveguides with parabolic profiles. It shows that the photons in the non-uniform optical waveguide propagate along z-axis in spiral form, j...This paper gives the strict solution of optical field equation in the optical waveguides with parabolic profiles. It shows that the photons in the non-uniform optical waveguide propagate along z-axis in spiral form, just like a charged particles moving in the magnetic field. Only in the step-index waveguides, it can the photons propagate in ziging form.展开更多
文摘Electromagnetic forming （EMF） is a high velocity forming process that uses impulse magnetic force. Coil is an important component of EMF system which needs to be designed depending on application. Flat spiral coils are generally used for electromagnetic forming of sheet metals. However, with this type of coil the central portion of the workpiece experiences marginal magnetic force. This leads to in-sufficient deformation at this portion and other problems like air entrapment. In this study, a conceptual design of flat coil was proposed for better distribution of magnetic forces over the workpiece. Comparative analysis of distribution of magnetic force, magnetic field and current density using the proposed and the existing coil designs were carried out using FEM. The result indicates that the proposed coil design produces comparatively better magnetic force distribution over the workpiece. Calculation of self-inductance of such coils was also carried out and was compared with FE simulation.
文摘The numeric al simulation study on the temperature distribution of underground field for the ground coupled heat pump (GCHP) with vertical spira l coil was carried out by using finite element. The distribution and recovery of undergroun d field temperature under different operation ratio and the optimal operation ratio were simulated.The performance parameters, i.e. inlet and outlet temperature of the ground spiral coil in heating and cooling modes were tested, the heat extracted or emitted by the heat pump to the ground was calculated, and the coefficients of performance (COP) of GCHP at heat ing and cooling modes were analyzed.
文摘This paper gives the strict solution of optical field equation in the optical waveguides with parabolic profiles. It shows that the photons in the non-uniform optical waveguide propagate along z-axis in spiral form, just like a charged particles moving in the magnetic field. Only in the step-index waveguides, it can the photons propagate in ziging form.
