Accurate computing method used for pipeline resistance coefficient and based on numerical computation

Abstract

The invention discloses an accurate computing method used for a pipeline resistance coefficient and based on numerical computation. According to the method, ANSYS-CFX is adopted to perform numerical simulation on a pipeline, and the temperature set in the numerical simulation and computed fluid energy loss per unit mass are in data comparison with the temperature obtained through experimental measurement and fluid energy loss per unit mass; and through the comparison, the temperature and the dynamic viscosity which are set in the numerical simulation are corrected, an optimal turbulence model is selected finally, and three-dimensional viscidity steady numerical simulation is performed on the pipeline under the conditions of different roughness and different flows. Each overflowing section total pressure obtained through the simulation is taken into a Bernoulli equation, and an on-way resistance coefficient and a local resistance coefficient of the pipeline under different conditions are inversely solved through the energy loss; and the data are guided into TableCurve3D for three-dimensional data curved surface fitting, and finally an optimal expression of the on-way and local resistance coefficients relative to relative roughness and Reynolds number is obtained. According to the accurate computing method, not only can the on-way and local resistance coefficients be accurately computed, but also an energy performance computation model of the pipeline system can be established on that basis, and energy-saving transformation is performed on the conventional pipeline system.

Description

technical field [0001] The invention belongs to the field of pipeline system energy performance calculation, in particular to an accurate calculation method for pipeline resistance coefficient based on numerical calculation. Background technique [0002] At present, the value of the resistance coefficient of the pipeline system is still calculated according to the empirical formula summed up by people in the 1940s. Among them, the calculation formula of the resistance coefficient along the way is mainly the calculation formula summarized by Nicholas’ experiment. In the experiment, Nicholas artificially bonded grain sand on the pipe wall to make an artificial rough pipe, so that different pipe diameters, Experiments were carried out on pipelines with different flow rates to obtain the empirical calculation formula of resistance coefficient along the way. However, this kind of artificial rough pipe is somewhat different from the rough pipe system in engineering practice, and ...

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Problems solved by technology

The Journal of System Simulation "Determination of Low Reynolds Number Local Resistance Coefficient by Distributed Parameter Method" (No. 9, 2009) established a mathematical model of local loss with the distributed parameter method, and calculated the local resistance coefficient of right-angle steering at low Reynolds number. However, This research is only for low Reynolds number local flow state, not applicable to other working conditions

The Journal of North China Institute of Water Conservancy and Hydropower "Application of Gray Linear Regression Combined Model in Calculating Resistance Coefficient of Water Supply Pipeline" (No. 1, 2009) uses the gray linear regression combined model to solve the problem, and obtains the relationship between the calculation of pipeline resistance coefficient and the relationship between pipe diameter and service time. mathematical model, but does not involve the influence of pipeline roughness and different working conditions

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