Numerical simulation of fluid flow and heat transfer in microchannels.

摘要

The drop-on-demand ink jet printer is quite a popular device for the production of high-resolution computer-graphics hard copy. The controlled production of a single ink drop is achieved through the action of a sudden pressure pulse produced by a piezoelectric device in the printheads with piezoelectric actuators. In order to enhance our fundamental understanding and control of the drop development phenomenon and therefore increase the resolution of the computer-graphics hard copy, it is very important to know how ink flows in the manifold device of the printhead. The objective of this study is to develop an accurate and fast numerical method for solving the flow fields in the manifold device.; The manifold of the ink jet printhead is modeled by several microchannels respectively with the vertical dimensions of the microchannels much smaller than the other two horizontal dimensions. Viscous and slightly compressible fluid flows which have similar physical properties as the ink is used to simulate the ink flows within the manifold. Both the microchannel configurations and the slightly compressible character of the fluid flow are very typical in simulating the ink flows through the maniflod and are amenable to significant simplifications of the Navier-Stokes equations and energy equations for more efficient numerical computations. Based on the simplified system of governing equations and assumptions of the fluid properties, a bicharacteristic based finite difference numerical scheme is developed to solve the system of simplified, slightly compressible, viscous microchannel flows. The computed results are validated with either analytical solutions or solutions from commercial CFD code (FLOW3D). Furthermore, an attempt is also made to study the temperature distributions within the microchannels as the fluid flows through the microchannels.