Mitigation of Transient Fluctuations During Flow Boiling in Microchannels via Adaptive Vapor Venting

Efficient thermal management is crucial for enhancing the performance and reliability of electronic devices. In this regard, flow boiling with microchannels promises high heat dissipation capability for a nominal temperature budget as it inherently takes advantage of high latent heat of vaporization along with high surface-area-to-volume ratio. However, the promise of high heat dissipation in flow boiling microchannels is limited by two-phase flow instabilities which cause large-amplitude temperature and pressure fluctuations. The current state-of-the-art thermal management techniques for enhancing heat transfer during flow boiling in microchannels operate in steady-state condition and provide sufficient continuous cooling to address the peak thermal loads. While such approaches can manage the thermal challenge, they result in significant cooling overdesign. To eliminate the overdesign, we introduce an adaptive vapor venting strategy which continuously adjusts to the varying vapor generation across different heat fluxes to completely mitigate two-phase fluctuations. Our results demonstrate that significant transient temperature fluctuations (±5 °C) in the conventional microchannels were completely eliminated with the incorporation of the adaptive vapor venting (within the experimental uncertainty). Furthermore, our results show that this strategy has the capability to handle transience and accordingly avoid the need for cooling overdesign.