Abstract
Micro-grooves are a crucial feature in many applications, such as microelectro-mechanical systems, drug delivery, heat pipes, sorption systems, and microfluidic devices. Micro-grooves utilize capillary action to deliver a liquid, with no need for an extra pumping device, which makes them unique and desirable for numerous systems. Although the capillary action is well studied, all the available equations for the capillary rise are case-specific and depend on the geometry of the groove, surface properties, and the transport liquid. In this study, a unified non-dimensional model for capillary rise is proposed that can accurately predict the capillary rise for any given groove geometry and condition and only depends on two parameters: contact angle and characteristic length scale, defined as the ratio of the liquid–vapor to the solid–liquid interface. The proposed model is compared against data from the literature and can capture the experimental results with less than 10% relative difference. The effect of the grooves’ height, width, and contact angle is investigated and reported. This study can be used for a unified approach in designing heat pipes, capillary-assisted evaporators for sorption systems, drug delivery micro-fluidic devices, etc.
Highlights
Micro-grooves are a crucial feature in many applications, such as microelectro-mechanical systems, drug delivery, heat pipes, sorption systems, and microfluidic devices
The objective of this paper is to provide an analytical solution to the capillary rise in micro-grooves by using a fundamental approach and to propose a unified equation
It is seen that the capillary rise in a triangular groove is considerably higher than that in a rectangular cross-section
Summary
Micro-grooves are a crucial feature in many applications, such as microelectro-mechanical systems, drug delivery, heat pipes, sorption systems, and microfluidic devices. Hopkins et al.[1] experimented with flat miniature heat pipes to determine the maximum heat flow rate and heat flux for different operating temperatures They concluded that heat pipes with deep and narrow capillary grooves produce the best results while most of their data showed that the heat flux bottleneck of the evaporator was the capillarity limitation. Vapor chambers or flat heat pipes are of particular interest and are used extensively in electronic devices due to their reliability, simplicity, passive operational mode, and effective heat transport capacity[4]. They remove the need for active liquid-cooling while providing a high-performance heat removal capability. Weibel and Garimella[4] note that the high performance of heat pipes and vapor chambers depends on the capillary pressure generated by the wick material so that it can overcome the viscous and inertial pressure drops along the vapor and liquid flow paths
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
