研究潜艇热尾流的浮升扩散规律和水面红外特征对红外探潜具有重要意义。以潜艇缩比模型为研究对象,建立了潜艇热尾流三维计算模型。分别使用重叠网格、VOF(Volume of Fluid)模型方法和来流法,对潜艇热尾流的浮升扩散过程进行了数值模拟...研究潜艇热尾流的浮升扩散规律和水面红外特征对红外探潜具有重要意义。以潜艇缩比模型为研究对象,建立了潜艇热尾流三维计算模型。分别使用重叠网格、VOF(Volume of Fluid)模型方法和来流法,对潜艇热尾流的浮升扩散过程进行了数值模拟。分析了潜艇热尾流的浮升扩散规律和温度场特征。使用实验测得的水面红外热像图和热尾流浮升扩散图像对两种仿真方法的精度进行了对比验证。结果表明:基于重叠网格和VOF模型的数值模拟方法精度较高,模拟得到的热尾流最大温度出现时间相差0.2 s,温度偏差为0.003 K,能够很好地模拟潜艇热尾流的浮升扩散和温度分布特性。展开更多
A new dynamic equation of aerosol in air is derived, using a model-in-model, by equilibrium of buoyancy, gravity and pressure, together with conservation laws of mass, momentum and energy via Reynolds transport theore...A new dynamic equation of aerosol in air is derived, using a model-in-model, by equilibrium of buoyancy, gravity and pressure, together with conservation laws of mass, momentum and energy via Reynolds transport theorem and supplemented by corresponding scientific laws for related properties of air and aerosols. This new dynamic equation of aerosol in air is a set of non-linear partial differential equations involved six unknown functions of mass densities, pressure, air and aerosol speeds and temperature. It has features: 1, it belongs to certain type;2, it emphases the effect of buoyancy in equilibrium and potential energy, and the Archimedes principle of buoyancy is firstly extended to lateral directions based on logical deduction, the phenomenon of stirring a glass of oil-water mixture and the recorded of Hurricane Isabel (2003) from space station. The later shows the evidence of existence of lateral buoyancy;3, the mass densities of air and aerosol of a point in our model are varied in different directions due to traction and are treated as vectors, and they have been used in the calculation of lateral buoyancy.展开更多
A numerical simulation model is developed for a laminar hydrogen/air diffusion flame. Nineteen species and twenty chemical reactions are considered. The chemical kinetics package (CHEMKIN) subroutines are employed to...A numerical simulation model is developed for a laminar hydrogen/air diffusion flame. Nineteen species and twenty chemical reactions are considered. The chemical kinetics package (CHEMKIN) subroutines are employed to calculate species thermodynamic properties and chemical reaction rate constants. The flow field is calculated by simultaneously solving a continuity equation, an axial momentum equation and an energy equation in a cylindrical coordinate system. Thermal diffusion and Brownian diffusion are considered in the radial direction while they are neglected in the axial direction. The results suggest that the main flame is buoyancy-controlled.展开更多
文摘研究潜艇热尾流的浮升扩散规律和水面红外特征对红外探潜具有重要意义。以潜艇缩比模型为研究对象,建立了潜艇热尾流三维计算模型。分别使用重叠网格、VOF(Volume of Fluid)模型方法和来流法,对潜艇热尾流的浮升扩散过程进行了数值模拟。分析了潜艇热尾流的浮升扩散规律和温度场特征。使用实验测得的水面红外热像图和热尾流浮升扩散图像对两种仿真方法的精度进行了对比验证。结果表明:基于重叠网格和VOF模型的数值模拟方法精度较高,模拟得到的热尾流最大温度出现时间相差0.2 s,温度偏差为0.003 K,能够很好地模拟潜艇热尾流的浮升扩散和温度分布特性。
文摘A new dynamic equation of aerosol in air is derived, using a model-in-model, by equilibrium of buoyancy, gravity and pressure, together with conservation laws of mass, momentum and energy via Reynolds transport theorem and supplemented by corresponding scientific laws for related properties of air and aerosols. This new dynamic equation of aerosol in air is a set of non-linear partial differential equations involved six unknown functions of mass densities, pressure, air and aerosol speeds and temperature. It has features: 1, it belongs to certain type;2, it emphases the effect of buoyancy in equilibrium and potential energy, and the Archimedes principle of buoyancy is firstly extended to lateral directions based on logical deduction, the phenomenon of stirring a glass of oil-water mixture and the recorded of Hurricane Isabel (2003) from space station. The later shows the evidence of existence of lateral buoyancy;3, the mass densities of air and aerosol of a point in our model are varied in different directions due to traction and are treated as vectors, and they have been used in the calculation of lateral buoyancy.
基金Supported by the National Natural Science Foundationof China (No. 5 0 0 0 6 0 0 5 ) the Research Fund fromEnvironm ental Institute of Tsinghua University and theOutstanding Young Professor Prize of the Ministry ofEducation of China
文摘A numerical simulation model is developed for a laminar hydrogen/air diffusion flame. Nineteen species and twenty chemical reactions are considered. The chemical kinetics package (CHEMKIN) subroutines are employed to calculate species thermodynamic properties and chemical reaction rate constants. The flow field is calculated by simultaneously solving a continuity equation, an axial momentum equation and an energy equation in a cylindrical coordinate system. Thermal diffusion and Brownian diffusion are considered in the radial direction while they are neglected in the axial direction. The results suggest that the main flame is buoyancy-controlled.
