The size of the nanoparticles prepared with the flow - levitation method can be controlled by controling the gas pressure in the action tube , the velocity of cooling gas flow and the temperature in the melt metal globule 自悬浮定向流方法制备纳米铝粉和铜粉的过程中，通过控制反应管内的气体压力、冷却气体的流速、熔球的温度等因素可以对粉体的尺寸分布进行控制。
2 . the investigation on the condensation heat transfer characteristics in a horizontal micro - fin tube for hc600a - oil mixture shows : a . the condensation heat transfer coefficient of the mixture increases with the increasing of the mass flux 2 、关于hc600a含油混合物水平微肋管内的冷凝换热特性的研究表明：混合物微肋管内冷凝平均换热系数随着质量流率的增加而增加。
At present , the study of water in smooth helical tube , of which the main work is about critical heat flux ( chf ) , is the primary concern of the research about the two - phase flow and heat transfer in curved pipe 目前螺旋管内两相流动传热研究主要以光滑螺旋管内的两相流动传热为主，其研究重点为临界热流密度( chf ) ，但对制冷剂在微肋螺旋管内两相流动传热还鲜见报道。
( 2 ) the investigation on the condensation heat transfer characteristics in a horizontal micro - fin tube for hc290 - oil mixture shows : a ) the condensation heat transfer coefficient of the mixture increases with the increasing of the mass flux ( 2 )关于hc290含油混合物水平微肋管内的冷凝换热特性的研究表明： a )随着质量流率的增加，混合物微肋管内冷凝平均换热系数增加。
The investigation on the evaporation heat transfer characteristics in a horizontal micro - fin tube for r290 - 3gs mixture shows : a ) the average evaporation heat transfer coefficient of the mixture increase with the increasing of the mass flux R290含油混合物在水平微肋管内流动沸腾换热特性的实验研究表明： a )随着质量流率的增加，含油混合物微肋管内的沸腾平均换热系数增加。
The experiment of condensation of steam in the presence of air was performed in a single vertical tube in a closed system consisted of the condenser tube , boiler , condensate separator drum , and connection lines from the boiler to the condenser tube 在中压回路上进行单根竖直管内的蒸汽冷凝实验。冷凝段的主要几何参数为：冷凝管内径为0 . 049m ，外径为0 . 055m ，长度为3 . 5m ；外套管内径为0 . 067m 。
We successfully apply the two - fluid model ( tfm ) to the study of two dimensional and three dimensional dense gas - solid flow characteristics . the results show some rules on the particle collisions and gas particle interactive influence of the vertical upward pipe 在对高浓度气固两相流的研究中，成功的运用双流体模型对两维和三维垂直立管段进行了研究，揭示了垂直立管内的高浓度气固流动的颗粒碰撞以及气相和颗粒相的相互影响的一些规律。
Next , aiming at the state of the art in engineering turbulence models , one extended explicit algebraic reynolds stress model to simulate anisotropic buoyant turbulent flows . validation was done using experimental and other numerical results of turbulent thermal mixing in t - junction flows 进一步的，针对当前考虑浮力作用紊流模型的研究现状，导出了适合模拟各向异性的浮力紊流的显式代数雷诺应力模型，并利用t型交叉管内的温度混合试验成果进行了分析验证。
The end show that coefficient of convective heat transfer at thermal boundary condition is higher than that at definite heat flux boundary condition . if according to dimensionless equation of heat convection , nu number of the latter almost is mutiplied 1 . 47 times of the formal , but the coefficient of convective heat transfer in tube between this two condition is almost equal 研究结果表明:在实验室中电加热方式得到的管外对流换热系数低于工程中传热条件下的管外对流换热系数,若按传热准则式关系,后者的努谢尔特数约为前者的1 . 4倍;而管内的对流换热系数在两种边界条件下的差别不大。
Based on prandtl ' s momentum transportation , this paper calculates in detail the physical quantities such as eddy viscosities , and ratio of eddy viscosity to motion viscosity , total stresses with respect to relative position in three regions of viscous sub - layer , buffer layer , and main turbulent stream for non - newtonian fluid flowing turbulently in ducts , which according to karman ' s three layer models and measurement of fluid parameters in evaluation apparatus , discusses the influence of polymer drag reduction on flowing properties of non - newton fluid , analyzes quantitatively principle of turbulent reduction phenomenon and condition of increasing reduction rate 摘要以普兰德动量传递理论为基础，按照卡门的三层模型，通过室内模拟环道用0号柴油及加入减阻剂在圆管内的流动参数的测定，计算了非牛顿型流体管内湍流边界层的层流内层、过渡层、湍流中心的涡流粘度，涡流粘度与运动粘度比、总应力随相对位置的变化等定量参数，探讨了高分子减阻剂对非牛顿流体流动特性的影响，对湍流减阻现象的机理与增大减阻率的条件进行了定量分析。
