Verification and Validation of a Network Algorithm for Single-phase Flow Modeling using Microfluidic Experiments

This paper presents the results of the full-scale verification and validation of the mathematical model and numerical algorithm for the network computation of a single-phase flow in a highly branched pipeline chain. The essential difference of this work from others is that highly branched hydraulic networks with homogeneous and non-uniform permeability, containing more than 70 thousand branches, are considered. Such branched networks are important in many applications. Therefore, the development of algorithms for calculating flows in such networks is very important. The network model is based on hydraulic theory, and the numerical algorithm relies on the network analogue of the well-known control volume method. At the same time, obtaining reliable experimental data for testing models for calculating very branched hydraulic networks is very difficult. In this work, microfluidic technologies are used to solve this problem. Data of laboratory experiments, obtained using microfluidic models of branched networks with homogeneous and heterogeneous permeability, containing several tens of thousands of branches, as well as CFD simulation results in full 3D formulation employing the fine computational grids were used to validate the model. The Reynolds number ranged from 0.81 to 13. Conducted validation has shown a good qualitative and quantitative concordance of the results of network and hydrodynamic simulation, as well as the data of the microfluidic experiments. The error in determining the total pressure drop in the branched hydraulic network with heterogeneous permeability, containing 37,855 nodes and 74,900 branches, did not exceed 5%. It has been demonstrated that the speed of solving a single-phase flow problem in a highly branched chain using network simulation techniques is 60 times more of magnitude higher as compared to CFD simulation at virtually the same accuracy.