Uniform velocity distribution can be obtained within a very short distance from the outlet of the nozzle.Heat and mass transfer near the meniscus can be remarkably activated comparedwith a conventional straight type immersion nozzle without swirl.Swirl helps the superheat in the melt dissipate,Penetration depth of nozz[e outlet flow is decreased remarkably by the application of swirling.Those findings mentioned above are very useful to control the flow pattern in the biliet and bloom continuous casters,

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In addition. the mechanism for obtaining the uniform velocity profile at the nozzle outlet was correlated with the flow pattern of the nozzle and the strength of the swirl. This is also done for a system in which swirl is generated by a rotating magnetic field imposed on the pouring tube. The model shows how the flow of steel from the nozzle may be modified using such a system. Such a swirling flow can provide a uniform, Iow velocity at the nozzle exit, which may be highly desirable for continuous casting purposes.

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In the present work, dissipative particle dynamics (DPD) simulation of simple flows is studied based on coarse-graining parameter. Reference scales of DPD are expressed in terms of physical units and DPD parameters and equations are expressed in terms of Reynolds number and apparent Peclet number. DPD parameters for a given coarse-graining are calculated by matching the density and viscosity of water and Reynolds number of the flow. The formulation is applied to water flow in microchannels of height 5 and 10 lm and tested for a wide range of coarse-graining parameter varying from 10 7 to 10 9 . The results are in a good agreement with the continuum formulation and simulated the correct hydrodynamics of water flow in microchannels. By inspecting the microscopic detail of the interaction between the DPD particles, it is found that diffusivity is low for high coarsegraining parameter, which results in higher values of Schmidt number. Parameters are tested within the continuum assumption. It is shown that correct Schmidt number can be achieved using small coarse-graining parameter. Also, it is observed that low diffusivity or high Schmidt number does not affect the hydrodynamics of water.

Poiseuille number, the product of friction factor and Reynolds number (fRe) for quasi-fully-developed gas microchannel flow in the slip flow regime, was obtained numerically based on the arbitrary-Lagrangian-Eulerian method. Two-dimensional compressible momentum and energy equations were solved for a wide range of Reynolds and Mach numbers for constant wall temperatures that are lower or higher than the inlet temperature. The channel height ranges from 2 μm to 10 μm and the channel aspect ratio is 200. The stagnation pressure pstg is chosen such that the exit Mach number ranges from 0.1 to 1.0. The outlet pressure is fixed at atmospheric conditon. Mach and Knudsen numbers are systematically varied to determine their effects on fRe. The correlation for fRe for the slip flow is obtained from that of fRe of no-slip flow and incompressible theory as a function of Mach and Knudsen numbers. The results are in excellent agreement with the available experimental measurements. It was found that fRe is a function of Mach and Knudsen numbers and is different from the values by 96/(1+12Kn) obtained from the incompressible flow theory.