Numerical simulation of pressure drop for three-dimensional rectangular microchannels

Purpose The purpose of this paper is to numerically investigate the flow characteristics and extend the data of friction factor and Reynolds number product of hydrodynamically developing laminar flow in three-dimensional rectangular microchannels with different aspect ratios. Design/methodology/approach Using a finite-volume approach, the friction factor characteristics of Newtonian fluid in three-dimensional rectangular ducts with aspect ratios from 0.1 to 1 are conducted numerically under no-slip boundary conditions. A simple model that approximately predicts the apparent friction factor and Reynolds number product f(app)Re is referenced as a semi-theoretical fundamental analysis for numerical simulations. Findings The accurate and reliable results of f(app)Re are obtained, which are compared with classic numerical data and experimental data, and the simple semi-theoretical model used and all comparisons show good agreement. Among them, the maximum relative error with the classic numerical data is less than 3.9 per cent. The data of f(app)Re are significantly extended to other different aspect ratios and the novel values of f(app)Re are presented in the tables. The characteristics of f(app)Re are analyzed as a function of a non-dimensional axial distance and the aspect ratios. A more effective and accurate fourth-order fitting equation for the Hagenbach's factor of rectangular channels is proposed. Originality/value From the reliable data, it is shown that the values of f(app)Re and the model can be references of pressure drop and friction factor for developing laminar flow in rectangular channels for researchers and engineering applications.