Boiling heat transfer enhancement by self-excited vibration

Unno, Noriyuki; Yuki, Kazuhisa; Taniguchi, Jun; Satake, Shin‐ichi

doi:10.1016/j.ijheatmasstransfer.2020.119588

Cited by 20 publications

(12 citation statements)

References 16 publications

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“…To further improve the HTC without decreasing the CHF, we recently developed a technique using a boiling bubble resonator (BBR), which is a vibration material attached close to the heating surface (Unno et al, 2020). The BBR is selfexcited by the growth and collapse of boiling bubbles, which results in continuous vibration with no applied external forces.…”

Section: In a Boiling Bubble Resonatormentioning

confidence: 99%

“…Then, the voltage was increased in 5-V increments to control the heat flux of the heat transfer surface. The heat flux and the wall superheat were calculated using the same method as described in our previous study (Unno et al, 2020), with the assumption that the temperature varies linearly between the values measured by the three thermocouples. In this study, CHF is defined as the maximum heat flux measured under steady-state conditions before the temperature rapidly increased to above 200 °C.…”

Section: Experimental Apparatusmentioning

confidence: 99%

“…A thin brass plate was used as the BBR; its width, total length and thickness were 10 mm, 30 mm and 100 μm, respectively. This is the same size as used in our previous study (Unno et al, 2020). The vibrating length, L (m), was measured with a caliper and the edges of the brass plate were fixed by pressing against polycarbonate blocks.…”

Section: Binding Conditions Of Boiling Bubble Resonatormentioning

confidence: 99%

See 2 more Smart Citations

Effect of the gap height between the vibration plate and heating surface on boiling heat transfer in a boiling bubble resonator

Unno

Yuki

Taniguchi

et al. 2021

JTST

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Section: In a Boiling Bubble Resonatormentioning

confidence: 99%

Section: Experimental Apparatusmentioning

confidence: 99%

Section: Binding Conditions Of Boiling Bubble Resonatormentioning

confidence: 99%

See 1 more Smart Citation

Effect of the gap height between the vibration plate and heating surface on boiling heat transfer in a boiling bubble resonator

Unno

Yuki

Taniguchi

et al. 2021

JTST

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“…We have previously proposed a new technique of using a boiling bubble resonator (BBR) [1][2][3] to enhance heat transfer in pool boiling without the conventional fabrication process associated with complex heat transfer surfaces [4][5][6]. In this technique, an interference plate, which can vibrate above a heat transfer surface because the plate is partially fixed or supported, is used as a BBR.…”

Section: Introductionmentioning

confidence: 99%

Visualization and Sound Measurements of Vibration Plate in a Boiling Bubble Resonator

Ono

Unno

Yuki

et al. 2021

Fluids

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We developed a boiling bubble resonator (BBR) as a new heat transfer enhancement method aided by boiling bubbles. The BBR is a passive device that operates under its own bubble pressure and therefore does not require an electrical source. In the present study, high-speed visualization of the flow motion of the microbubbles spouted from a vibration plate and the plate motion in the BBR was carried out using high-speed LED lighting and high-speed cameras; the sounds in the boiling chamber were simultaneously captured using a hydrophone. The peak point in the spectrum of the motion of the vibration plate and the peak point in the spectrum of the boiling sound were found to be matched near a critical heat-flux state. Therefore, we found that it is important to match the BBR vibration frequency to the condensation cycle of the boiling bubble as its own design specification for the BBR.

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“…For the studies of vibration and excitation force of two-phase flow, Seryakov studied the boiling resonance phenomenon in heat pipes and analyzed the pulsation characteristics of the heat pipe under boiling state [4]. Unno and Yuki et al studied the relationship between plate vibration and boiling heat transfer coefficient under the condition of subcooled boiling heat transfer based on the natural vibration frequency of the heating plate [5]. Elkholy and Kempers carried out experiments on the geyser boiling phenomenon in two-phase flow circulation, and studied the influence of parameters such as fluid state and heat flux on fluid vibration [6].…”

Section: Introductionmentioning

confidence: 99%

Research on Noise Reduction of 3.6 MW Evaporative Cooling Wind Motor Induced by Electromagnetic and Two-Phase Flow Resonance Based on Stator Optimization

et al. 2021

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In this paper, the vibration frequency of the stator of 3.6 MW fully immersed evaporative cooling permanent magnet semi-direct drive generators (ECPMSDDGs) was analyzed based on the fluid-structure coupling theory and solved by finite element analysis (FEA) simulation. The resonance noise reduction research under the typical working condition induced by two-phase flow and electromagnetic force was studied based on the method of structural optimization. In this paper, a structural optimal design method for the stator of the 3.6 MW ECPMSDDGs was presented. First of all, the frequency and characteristics of electromagnetic force of 3.6 MW ECPMSDDGs under the rated power were analyzed. Secondly, the frequency and characteristics of two-phase flow boiling vibration were analyzed based on the bubble oscillation theory of the two-phase flow and the experiment. Thirdly, the wet modal natural frequency of the stator core cooling structure was analyzed based on the fluid-structure coupling theory and FEA. Finally, the natural wet mode vibration frequency of the stator cooling structure of the 3.6 MW ECPMSDDGs was improved based on the structure optimization. This optimization method could reduce the resonance noise of evaporative cooling motor induced by electromagnetic and two-phase flow. The optimization results showed that the natural wet mode frequency of the stator could be improved by optimizing the radial flow groove and supporting beam under the condition that the effective length of the stator core remained unchanged during the optimization. The noise simulation result showed that the resonance noise of 3.6 MW ECPMSDDGs induced by electromagnetic and two-phase flow could be reduced after the structural optimization.

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Boiling heat transfer enhancement by self-excited vibration

Cited by 20 publications

References 16 publications

Effect of the gap height between the vibration plate and heating surface on boiling heat transfer in a boiling bubble resonator

Effect of the gap height between the vibration plate and heating surface on boiling heat transfer in a boiling bubble resonator

Visualization and Sound Measurements of Vibration Plate in a Boiling Bubble Resonator

Research on Noise Reduction of 3.6 MW Evaporative Cooling Wind Motor Induced by Electromagnetic and Two-Phase Flow Resonance Based on Stator Optimization

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