Electroosmotic flow in optimally operated micro heat pipes

Abstract

Micro heat pipe, a capillary-driven two-phase heat transfer microsystem, serves as an effective cooling device for electronic components. Based on a mathematical model employing the conservation laws to yield the heat and fluid flow characteristics of a micro heat pipe, we demonstrate how the basic principles of electroosmotic flow can be applied to enhance the performance of micro heat pipes. To provide a thorough and comprehensive analysis, both favorable and adverse effects of electroosmotic flow on the thermal performance of a micro heat pipe are studied. The thermal performance of a micro heat pipe is strongly dependent on the circulation effectiveness of working fluid. A well-defined parameter is employed to characterize the effects of the electric force on the circulation effectiveness of the working fluid with different ion concentrations. The aiding effect of electric force increases the circulation rate of working fluid, resulting in a significant enhancement in the heat transport capacity of micro heat pipe. By investigating the solid wall temperature profiles, the use of electroosmosis in enhancing the thermal performance of a micro heat pipe is deemed to be practically feasible due to the fact that significant enhancement can be achieved with a compensation of small temperature drop at a reasonably low applied voltage.