  We propose a new class of wicks, consisting of closely packed circular rods,
whose evaporative capacities have been measured at different heat loads ranging
between 0.05W/cm^2 and 8W/cm^2. The experiments were performed with two
different liquids, water and highly volatile pentane, in a specially designed
setup to understand transient and steady state cooling characteristics of the
proposed wicks. Heat interception and vapour release occur on the same side in
these experiments. These wicks released ~50% of the supplied heat load as the
latent heat; this value remained nearly constant between the explored heat
loads. These wicks have the unique characteristic of potentially very high and
rapid capillary rise induced by near-zero radii (NZR) of contacts formed
between the rods in contact; liquid region reaching the end in NZR has been
called corner meniscus. While the bulk liquid (present between three rods) may
recede, depending on the heat load, the corner meniscus remains pinned; this
unique feature thus leads to sustained high evaporation rate requirements. This
remarkable characteristic seems advantageous compared to a regular wick, whose
cooling performance depends on the heat loads. We also performed 3-D unsteady
state numerical simulations to understand the effect of rod diameter and
materials' thermal conductivity on the overall wick's performance. Steady state
temperature value was in fairly good agreement with the ones measured in
experiments. Based on the geometry of the corner film, fluid mechanics of
liquid transport, and the heat transfer aspects, we present a design of
suitable wicks as per the requirement. These new configurations can represent a
separate class of wicks and may replace the regular wicks in current and
futuristic cooling devices.
