| Pipe is an important project delivery tube system, of which the resistance has an important impact on loss of the entire pipeline design. Based on computational fluid dynamics (CFD), use Fluent simulation software as the computing platform, simulate typical operating conditions of pipe numerically, analyze the pressure and velocity distribution, study the pipe wall shear study stress distribution. According to compare the numerical simulation and empirical formula of the drag coefficient to verify the feasible method using numerical simulation method of calculating resistance loss, discuss the variation and mechanism of resistance loss. The results show that:(1) The total shear stress distribution in the bend is nonuniform. The polynomial fitting curve formulas along axial and circumferential direction of the pipe are deduced from simulation results, which provide a reference basis of calculating pipe total wall shear stress in the future;(2) This paper comprised the simulation values and experience values when the media is water, according to the Bernoulli equation and the experience formula. The local resistance coefficient calculated by those values are consistent. Thus, it is feasible to use Fluent to execute number simulation;(3) Impact bend resistance losses within the typical parameters, the fluid medium flow rate, pipe bending radius, wall roughness, Reynolds number are the sensitive parameters. They lost a greater impact on the bending resistance, the resistance loss of the analog value and the calculated value or less;(4) Non-Newtonian fluid, as the project application is extremely broad, and the Newtonian fluid viscosity changes with shear rate, so the resistance loss between the calculated value and the experience is a big error. Therefore, in calculating the resistance of non-Newtonian fluid loss, should not only refer to experience. The paper used for the CFD numerical simulation study is carried out to provide a way worthy of exploration. |
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