低粘附功管壁的内流减阻研究

Internal Flow Drag Reduction of Lower Adhesive Work between the Inwall of Conduit and Liquid

以乙烯基三乙氧基硅烷 无水乙醚溶液处理玻璃管道内壁 ,降低流体水与管壁间的粘附功 ,研究了低粘附功内壁管道的内流减阻性能。结果表明 ,在管壁与液体间的粘附功小于液体的内聚功条件下 ,当雷诺数大于临界雷诺数时 ,低粘附功内壁管道呈现明显的内流减阻效果 ,临界雷诺数的值与一定的临界壁面剪力值或层流底层临界厚度值相对应 ;在减阻区内 ,减阻率随雷诺数的增加及管道内径的减小而增大 ,阻力系数的无因次关联式可表示为λ=f (Re ,X) ,其中X为无因次数群 [W / (du2 ρ) ]。

The internal flow drag reduction property of inwall of lower adhesive work was investigated by treating the inwall of glass conduit with absolute diethyl ether solution of vinyl triethoxy silicane to depress the adhesive work between the inwall and fluid water. The result shows that the apparent drag reduction can be obtained when the Reynolds number of liquid is greater than the critical Reynolds number under condition that the adhesive work between inwall and liquid is smaller than the cohesive work of liquid. The value of critical Reynolds number corresponds to a certain value of critical wall shear or to a certain value of laminar sublayer critical thickness. In drag reduction region the drag reduction ratio increases as the Reynolds number increases or as the inside diameter of conduit decreases. The dimensionless correlation formula of resistance coefficient can be stated as λ=f (Re, X ), and X is the dimensionless number [ W/(du 2ρ )].