Flow boiling heat transfer in microgravity: Recent results

Celata, Gian Piero

doi:10.1007/bf02915738

Cited by 14 publications

(4 citation statements)

References 9 publications

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“…Some studies have been performed with the aim of better understanding the role of gravity on two-phase flow behavior (rather than parameters that provide gravity-insensitivity), but those efforts cannot be covered comprehensively in this paper due to length constraints. The authors refer readers searching for additional details to several review papers [18,[28][29][30].…”

Section: Summary Of Microchannel Definitionsmentioning

confidence: 99%

Gravity effects in microgap flow boiling

Robinson

Bar‐Cohen

2017

2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)

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Increasing integration density of electronic components has exacerbated the thermal management challenges facing electronic system developers. The high power, heat flux, and volumetric heat generation of emerging devices are driving the transition from remote cooling, which relies on conduction and spreading, to embedded cooling, which facilitates direct contact between the heat-generating device and coolant flow. Microgap coolers employ the forced flow of dielectric fluids undergoing phase change in a heated channel between devices. While two-phase microcoolers are used routinely in ground-based systems, the lack of acceptable models and correlations for microgravity operation has limited their use for spacecraft thermal management. Previous research has revealed that gravitational acceleration plays a diminishing role as the channel diameter shrinks, but there is considerable variation among the proposed gravity-insensitive channel dimensions and minimal research on rectangular ducts. Reliable criteria for achieving gravity-insensitive flow boiling performance would enable spaceflight systems to exploit this powerful thermal management technique and reduce development time and costs through reliance on ground-based testing. In the present effort, the authors have studied the effect of evaporator orientation on flow boiling performance of HFE7100 in a 218 μm tall by 13.0 mm wide microgap cooler. Similar heat transfer coefficients and critical heat flux were achieved across five evaporator orientations, indicating that the effect of gravity was negligible.

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Section: Summary Of Microchannel Definitionsmentioning

confidence: 99%

Gravity effects in microgap flow boiling

Robinson

Bar‐Cohen

2017

2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)

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“…Due to length constraints, additional studies are not covered here, but are covered in several review papers [10,[21][22][23].…”

Section: Orientation Effects In Flow Boilingmentioning

confidence: 99%

Orientation Effects in Two-Phase Microgap Flow

Robinson

Bar‐Cohen

2019

Journal of Electronic Packaging

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The high power density of emerging electronic devices is driving the transition from remote cooling, which relies on conduction and spreading, to embedded cooling, which extracts dissipated heat on-site. Two-phase microgap coolers employ the forced flow of dielectric fluids undergoing phase change in a heated channel within or between devices. Such coolers must work reliably in all orientations for a variety of applications (e.g., vehicle-based equipment), as well as in microgravity and high-g for aerospace applications, but the lack of acceptable models and correlations for orientation- and gravity-independent operation has limited their use. Reliable criteria for achieving orientation- and gravity-independent flow boiling would enable emerging systems to exploit this thermal management technique and streamline the technology development process. As a first step toward understanding the effect of gravity in two-phase microgap flow and transport, in the present effort the authors have studied the effect of evaporator orientation, mass flux, and heat flux on flow boiling of HFE7100 in a 1.01 mm tall × 13.0 mm wide × 12.7 mm long microgap channel. Orientation-independence, defined as achieving similar critical heat fluxes (CHFs), heat transfer coefficients (HTCs), and flow regimes across orientations, was achieved for mass fluxes of 400 kg/m2 s and greater (corresponding to a Froude number of about 0.8). The present results are compared to published criteria for achieving orientation- and gravity-independence.

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“…As is known, flow boiling can be a practical and effective method to prevent the formation of massive bubbles by liquid inertia to flush discrete bubbles away from the heated wall and sustain liquid replenishment of the heated wall. However, the flow boiling and vapor-liquid two-phase flow involve much more complicated mechanisms than that of the pool boiling, and only a few reports on flow boiling heat transfer in microgravity are available [21].…”

Section: Introductionmentioning

confidence: 99%