Frequency analysis of pressure oscillations in large length-to-diameter two-phase micro-channel heat sinks

Lee, Seung–Hyun; Devahdhanush, V.S.; Mudawar, Issam

doi:10.1016/j.ijheatmasstransfer.2017.08.107

Cited by 43 publications

(5 citation statements)

References 81 publications

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“…Over the ensuing decades through present day, researchers have continued investigating instabilities and transient behavior observed in experimental two-phase flow thermal management systems, focusing on DWOs [51][52][53][54], Parallel Channel Instability (PCI) [55][56][57], Pressure Drop Oscillations (PDOs) [58][59][60], and interaction of multiple instability modes [61,62]. Recent reviews, such as those by Tadrist [63], Kakac and Bon [64], and Ruspini et al [65] provide updated surveys of literature relating to phenomena first reported by Boure et al [50], including overviews of approaches taken towards modeling their behavior.…”

Section: Flow Boiling Instabilities and Transient Phenomenamentioning

confidence: 99%

“…In mini/macro channels (such as in the present FBM), however, vapor generation through nucleation is not of a scale comparable to hydraulic diameter, meaning other explanations must be present for the pressure and flowrate oscillations experimentally detected and associated with DWOs. This also severely limits the applicability of some existing correlations for frequency of oscillatory behavior, such as those recently investigated by Lee et al [60] for pressure oscillations in micro-channel boiling, which depend primarily on the nucleation process and associated surface tension effects.…”

Section: Density Wave Oscillations (Dwos) In Micro-channels Versus Mini/macro-channelsmentioning

confidence: 99%

“…Having used both transient pressure results and flow visualization image sequences to describe the characteristics of DWOs within the present system and prove that pressure fluctuations in the low-frequency (~0.5-10 Hz) range can be associated with cyclical passage of high and low density fronts (regions comprised of mostly liquid and mostly vapor, respectively), it is now possible to present a comprehensive overview of the DWO process. Before embarking, however, it should again be noted that this analysis applies to mini/macro-channels, and DWO formation and behavior in micro-channels is fundamentally different, something briefly discussed in a recent study by Lee et al [60].…”

Section: Explanation Of Density Wave Oscillation Phenomenonmentioning

confidence: 99%

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Experimental investigation of frequency and amplitude of density wave oscillations in vertical upflow boiling

O’Neill

Mudawar

Hasan

et al. 2018

International Journal of Heat and Mass Transfer

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Historically, study of two-phase flow instabilities has been arguably one of the most challenging endeavors in heat transfer literature due to the wide range of instabilities systems can manifest depending on differences in operating conditions and flow geometry. This study utilizes experimental results for vertical upflow boiling of FC-72 in a rectangular channel with finite inlet quality to investigate Density Wave Oscillations (DWOs) and assess their potential impact on design of two-phase systems for future space missions. High-speed flow visualization image sequences are presented and used to directly relate the cyclical passage of High and Low Density Fronts (HDFs and LDFs) to dominant low-frequency oscillations present in transient pressure signals commonly attributed to DWOs. A methodology is presented to determine frequency and amplitude of DWO induced pressure oscillations, which are then plotted for a wide range of relevant operating conditions. Mass velocity (flow inertia) is seen to be the dominant parameter influencing frequency and amplitude of DWOs. Amplitude of pressure oscillations is at most 7% of the time-averaged pressure level for current operating conditions, meaning there is little risk to space missions. Reconstruction of experimental pressure signals using a waveform defined by frequency and amplitude of DWO induced pressure fluctuations is seen to have only moderate agreement with the original signal due to the oversimplifications of treating DWO induced fluctuations as perfectly sinusoidal in nature, assuming they occur at a constant frequency value, and neglecting other transient flow features. This approach is nonetheless determined to have potential value for use as a boundary condition to introduce DWOs in two-phase flow simulations should a model be capable of accurately predicting frequency and amplitude of oscillation.

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Section: Flow Boiling Instabilities and Transient Phenomenamentioning

confidence: 99%

Section: Density Wave Oscillations (Dwos) In Micro-channels Versus Mini/macro-channelsmentioning

confidence: 99%

Section: Explanation Of Density Wave Oscillation Phenomenonmentioning

confidence: 99%

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Experimental investigation of frequency and amplitude of density wave oscillations in vertical upflow boiling

O’Neill

Mudawar

Hasan

et al. 2018

International Journal of Heat and Mass Transfer

Self Cite

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“…The results also indicated that heat transfer coefficient increased with increasing predominant frequency. Many other authors reported further important results related to the analysis of frequencies present in pressure and flow pattern fluctuations (Lee et al (2018), O'Neil et al (2018, Ma et al (2018), Monni et al (2014)).…”

Section: Introductionmentioning

confidence: 94%

On the nature of flow patterns and pressure drop fluctuations during flow boiling

Oliveira

Copetti

Indrusiak³

et al. 2021

International Journal of Multiphase Flow

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“…Present day researchers continue characterizing instabilities and transient behavior observed in experimental two-phase flow systems, focusing on DWOs [51][52][53][54][55], Parallel Channel Instability (PCI) [56][57][58], Pressure Drop Oscillations (PDOs) [59][60][61], and interaction of multiple instability modes [62,63]. Recent reviews, such as those by Tadrist [64], Kakac and Bon [65], and Ruspini et al [66] provide updated surveys of literature relating to phenomena first reported by Boure et al [50].…”

Section: Flow Boiling Instabilities and Transient Phenomenamentioning

confidence: 99%

Mechanistic model to predict frequency and amplitude of Density Wave Oscillations in vertical upflow boiling

O’Neill

Mudawar

2018

International Journal of Heat and Mass Transfer

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Modeling of two-phase flow transient behavior and instabilities has traditionally been one of the more challenging endeavors in heat transfer research due to the need to distinguish between a wide range of instability modes systems can manifest depending on differences in operating conditions, as well as the difficulty in experimentally determining key characteristics of these phenomena. This study presents a new mechanistic model for Density Wave Oscillations (DWOs) in vertical upflow boiling using conclusions drawn from analysis of flow visualization images and transient experimental results as a basis from which to begin modeling. Counter to many prior studies attributing DWOs to feedback effects between flow rate, pressure drop, and flow enthalpy causing oscillations in position of the bulk boiling boundary, the present instability mode stems primarily from body force acting on liquid and vapor phases in a separated flow regime leading to liquid accumulation in the near-inlet region of the test section, which eventually departs and moves along the channel, acting to re-wet liquid film along the channel walls and re-establish annular, cocurrent flow. This process was modeled by dividing the test section into three distinct control volumes and solving transient conservation equations for each, yielding predictions of frequencies at which this process occurs as well as amplitude of associated pressure oscillations. Values for these parameters were validated against an experimental database of 236 FC-72 points and show the model provides good predictive accuracy and capably captures the influence of parametric changes to operating conditions.

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Frequency analysis of pressure oscillations in large length-to-diameter two-phase micro-channel heat sinks

Cited by 43 publications

References 81 publications

Experimental investigation of frequency and amplitude of density wave oscillations in vertical upflow boiling

Experimental investigation of frequency and amplitude of density wave oscillations in vertical upflow boiling

On the nature of flow patterns and pressure drop fluctuations during flow boiling

Mechanistic model to predict frequency and amplitude of Density Wave Oscillations in vertical upflow boiling

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