By using Galerkin’s method, the finite element formulation is made for axisymmtric heat transfer problems for anisotropic materials from the heat transfer differential equations expressed in terms of heat fluid densi...By using Galerkin’s method, the finite element formulation is made for axisymmtric heat transfer problems for anisotropic materials from the heat transfer differential equations expressed in terms of heat fluid density. Results of an example show that the heat transfer anisotropy has an important effect on temperature field.展开更多
Based on the simplified format of the Reynolds stress equations, a fire-new rotational-modification method for the anisotropic turbulence model has been presented. A three-dimensional Navier-Stokes code with this new ...Based on the simplified format of the Reynolds stress equations, a fire-new rotational-modification method for the anisotropic turbulence model has been presented. A three-dimensional Navier-Stokes code with this new rotational modified k-ω turbulence models （β=0.1 and β=1） and the standard k-ω turbulence model have been used for the prediction of flow and heat transfer characteristics in a rotating smooth square channel. The Reynolds number Re based on the inlet velocity of the cooling air and hydraulic diameter is 6000 .The rotating speed are 300, 600, 900, 1200rpm respectively. The calculations results of using three turbulence models have been compared with the experimental data. The research results show that （1） the rotational modification coefficient Rf13 used in the new anisotropic k-ω model would increased/decreased the predictions of heat transfer on the trailing surface/leading surface compared to the standard k-ω model. And this tendency would be increased with the increased ft. （2） The simulation performance of the standard k-ω model was well on the leading surface. However, on the trailing surface it under-predicted the heat transfer at high rotating speed. （3） The calculation results of the new anisotropic k-ω model with β=0.1 proposed by the present paper agreed well with experimental data, both on the leading and trailing surfaces. Besides, compared to 1, 0.1 is a more appropriate magnitude of βat conditions in the present paper.展开更多
The in-plane thermal conductivity of the iron-based superconductor Ca10（Pt4δAs8）（（Fe1-xPtx）2As2）5 single crystal （＂10-4-8＂, Tc = 22 K） was measured down to 80 inK. In a zero field, the residual linear term ...The in-plane thermal conductivity of the iron-based superconductor Ca10（Pt4δAs8）（（Fe1-xPtx）2As2）5 single crystal （＂10-4-8＂, Tc = 22 K） was measured down to 80 inK. In a zero field, the residual linear term ro/T is negligible, suggesting the nodeless superconducting gaps in this multiband compound. In the magnetic fields, r0/T increases rapidly, which mimics the multiband superconductor NbSe2 and LuNi2B2C with highly anisotropic gap. Such a field dependence of K0/T is an evidence for the multiple superconducting gaps with quite different magnitudes or highly anisotropic gap. Compared with the London penetration depth results of the Ca10（Pt3As8）（（Fe1-xPtx）zAs2）5 （＂10-3-8＂） compound, the 10-4-8 and 10-3-8 compounds may have a similar superconducting gap structure.展开更多
文摘By using Galerkin’s method, the finite element formulation is made for axisymmtric heat transfer problems for anisotropic materials from the heat transfer differential equations expressed in terms of heat fluid density. Results of an example show that the heat transfer anisotropy has an important effect on temperature field.
文摘Based on the simplified format of the Reynolds stress equations, a fire-new rotational-modification method for the anisotropic turbulence model has been presented. A three-dimensional Navier-Stokes code with this new rotational modified k-ω turbulence models （β=0.1 and β=1） and the standard k-ω turbulence model have been used for the prediction of flow and heat transfer characteristics in a rotating smooth square channel. The Reynolds number Re based on the inlet velocity of the cooling air and hydraulic diameter is 6000 .The rotating speed are 300, 600, 900, 1200rpm respectively. The calculations results of using three turbulence models have been compared with the experimental data. The research results show that （1） the rotational modification coefficient Rf13 used in the new anisotropic k-ω model would increased/decreased the predictions of heat transfer on the trailing surface/leading surface compared to the standard k-ω model. And this tendency would be increased with the increased ft. （2） The simulation performance of the standard k-ω model was well on the leading surface. However, on the trailing surface it under-predicted the heat transfer at high rotating speed. （3） The calculation results of the new anisotropic k-ω model with β=0.1 proposed by the present paper agreed well with experimental data, both on the leading and trailing surfaces. Besides, compared to 1, 0.1 is a more appropriate magnitude of βat conditions in the present paper.
基金supported by the National Basic Research Program of China(Grant No.2012CB821402)the National Natural Science Foundation of China(Grant Nos.11422429 and 91421101)+1 种基金the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learningthe Science and Technology Commission of Shanghai Municipality of China(Grant No.15XD1500200)
文摘The in-plane thermal conductivity of the iron-based superconductor Ca10（Pt4δAs8）（（Fe1-xPtx）2As2）5 single crystal （＂10-4-8＂, Tc = 22 K） was measured down to 80 inK. In a zero field, the residual linear term ro/T is negligible, suggesting the nodeless superconducting gaps in this multiband compound. In the magnetic fields, r0/T increases rapidly, which mimics the multiband superconductor NbSe2 and LuNi2B2C with highly anisotropic gap. Such a field dependence of K0/T is an evidence for the multiple superconducting gaps with quite different magnitudes or highly anisotropic gap. Compared with the London penetration depth results of the Ca10（Pt3As8）（（Fe1-xPtx）zAs2）5 （＂10-3-8＂） compound, the 10-4-8 and 10-3-8 compounds may have a similar superconducting gap structure.
