Frequency Analysis of Pressure Oscillations in Subcooled Flow Boiling Through Microchannel Heat Sink Available to Purchase

The study presents frequency analysis of pressure drop oscillations in subcooled flow boiling through a MCHS. The analysis employs the Welch power spectrum method to estimate the dominant frequency, providing insights into the dynamic behavior of the flow oscillation. The Welch Power Spectrum method addresses its limitation related to spectral leakage by incorporating windowing, leading to more accurate and reliable spectral analysis, especially in scenarios involving non-stationary signals or noisy data. To control the backflow during flow boiling, a single disc spring loaded flow restrictor is incorporated before the inlet plenum of the MCHS. The impact of flow restrictor on pressure drop oscillations is comprehensively examined using Welch power spectrum across varying heat fluxes (25 W/cm² to 80 W/cm²) and mass fluxes (520 kg/m²s) in a high aspect ratio configuration (500μm channel height and 230μm channel width) of 44 parallel microchannels. This approach enables the identification of dominant frequencies linked to the flow boiling phenomenon, based on the temporal variation of pressure drop. Additionally, the research highlights the efficacy of the flow restrictor in mitigating flow boiling instability within the MCHS.