Modelling Free Jet Ejection on a System Level – An approach for microfluidics

Fast simulation of complex microfluidic systems requires consideration of network simulations based on lumped models as an alternative to standard computational fluid dynamic (CDF) simulations. In this paper we describe an analytical model of an orifice, capable of handling free jets and droplet ejection. It is intended to be used as a multipurpose model for simulations of microfluidic systems (e.g. ink-jet print heads or micro dispensers). The approach is based on distinction between different fluidic states occurring during operation. Whether the orifice is self-priming by capillary forces or ejecting a liquid jet driven by a certain pressure for example, different formulas are used to describe the flow. Though the used formulas are adopted from standard fluidic theory good agreement is found between simulations and experiments performed to validate the model.