Traveling-wave electrohydrodynamic micropumping induced in a temperature gradient
Abstract
Micropumping has emerged as a critical research area for many electronics and biological applications. A significant driving force behind this research has been integration of pumping mechanisms into micro Total Analysis Systems (μTAS) or similar multi-functional analysis techniques. However, electronics packaging, micromixing and microdosing systems, among others, have also exploited micropumping concepts. This work commences with a comprehensive review of the recent advances in micropump technologies, specifically within the last few years. Inclusion of critical selection criteria for both pumps and valves aid in determining which type of pumping mechanism is appropriate for a given application. Also, important limitations or incompatibilities are addressed. Quantitative comparison tables of various micropumping techniques are listed as tabular data for ready comparison. Of the micropumping techniques available, electrohydrodynamic (EHD) pumping is identified and explored for its viability in meeting convective cooling needs in the electronics market, and possibly providing a scalable pumping mechanism for microfluidics-based biomedical devices. A numerical model which uses a force-density approach and which was previously validated against analytical results is extended to investigate flow enhancement techniques. The model can provide transient as well as steady-state results. This numerical model along with the coupled momentum and charge conservation equations is used to model discrete electrode boundaries and optimize the operation of real devices. A recirculating flow loop experimental setup is developed for validation and flow measurement using a traveling-wave, induction EHD driving force. Fluid velocities are visualized and quantified using micro particle image velocimetry. The effects of applied voltage, frequency modulation, and externally applied are experimentally investigated and shown to offer means for increasing the fluid velocity. Pressure drop values are computed through numerical modeling and power measurements are attained experimentally. The heat removal capacity of the micropump developed is also estimated. Means for improving the flow rate generated by the pump are identified, along with suggestions for future work.
Degree
Ph.D.
Advisors
Garimella, Purdue University.
Subject Area
Mechanical engineering
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.