Effect of ionic liquid additives on temperature and pressure fluctuations during water flow boiling in microchannels

Abstract

Overheating of high-performance electronic devices is undesired for long-term reliability. In this regard, two-phase microchannel heat sinks promise high heat dissipation within small temperature budgets using the latent heat of vaporization of the boiling fluid. However, geometrical confinement induces thermofluidic fluctuations and prohibits the use of two-phase microchannel heat sinks in practical applications. Here we for the first-time report flow boiling experiments with surface-active ionic liquid (SAIL) as an additive in water. This concept is inspired by our results of pool boiling wherein bubble coalescence was avoided with SAIL. In comparison to the water where fluctuations were apparent in the slug flow regime, temperature and pressure fluctuations were nearly mitigated up to the heat flux of 700 kW/m2 with an ionic liquid solution. The suppression of instabilities is attributed to the delay in the formation of a big vapor bubble at the inlet of microchannels due to the non-coalescing nature of bubbles formed with the SAIL solution.