Experimental investigations on flashing-induced instabilities in one and two-parallel channels: A comparative study

Marcel, Christian Pablo; Rohde, M.; Hagen, T.H.J.J. van der

doi:10.1016/j.expthermflusci.2010.02.002

Cited by 36 publications

(16 citation statements)

References 18 publications

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“…This system is of interest to prevent mechanical damage in nuclear reactors and rocket vehicles [e.g., Murphy, 1965;Aritomi et al, 1993;Jiang et al, 1995]. The importance of heat flux and steam condensation on geysering has been documented [e.g., Goodykoontz and Dorsch, 1967;Boure et al, 1973;Casarosa et al, 1983;Aritomi et al, 1993;Marcel et al, 2010]. Other parameters also affect the geysering process: the water level and geometry of the vessel, as well as pressure and temperature differences driving water flow and heat transport [Lin et al, 1995;Tong et al, 2014;Chen et al, We measured the pressure and temperature of the water at a frequency of 100 Hz in most experiments using a HIOKI 8430 data logger with one pressure sensor (XPM10 from Measurement specialties) with an accuracy of <0.25% of full range, corresponding to 100 Pa for 40 kPa, and K-type thermocouples with an accuracy of $18C around 1008C.…”

Section: Introductionmentioning

confidence: 99%

“…This system is of interest to prevent mechanical damage in nuclear reactors and rocket vehicles [e.g., Murphy , ; Aritomi et al ., ; Jiang et al ., ]. The importance of heat flux and steam condensation on geysering has been documented [e.g., Goodykoontz and Dorsch , ; Boure et al ., ; Casarosa et al ., ; Aritomi et al ., ; Marcel et al ., ]. Other parameters also affect the geysering process: the water level and geometry of the vessel, as well as pressure and temperature differences driving water flow and heat transport [ Lin et al ., ; Tong et al ., ; Chen et al ., ].…”

Section: Introductionmentioning

confidence: 99%

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An experimental study of the role of subsurface plumbing on geothermal discharge

Namiki

Ueno

Hurwitz

et al. 2016

Geochem. Geophys. Geosyst.

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In order to better understand the diverse discharge styles and eruption intervals observed at geothermal features, we performed three series of laboratory experiments with differing plumbing geometries. A single, straight conduit that connects a hot water bath (flask) to a vent (funnel) can originate geyser‐like periodic eruptions, continuous discharge like a boiling spring, and fumarole‐like steam discharge, depending on the conduit length and radius. The balance between the heat loss from the conduit walls and the heat supplied from the bottom determines whether and where water can condense which in turn controls discharge style. Next, we connected the conduit to a cold water reservoir through a branch, simulating the inflow from an external water source. Colder water located at a higher elevation than a branching point can flow into the conduit to stop the boiling in the flask, controlling the periodicity of the eruption. When an additional branch is connected to a second cold water reservoir, the two cold reservoirs can interact. Our experiments show that branching allows new processes to occur, such as recharge of colder water and escape of steam from side channels, leading to greater variation in discharge styles and eruption intervals. This model is consistent with the fact that eruption duration is not controlled by emptying reservoirs. We show how differences in plumbing geometries can explain various discharge styles and eruption intervals observed in El Tatio, Chile, and Yellowstone, USA.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An experimental study of the role of subsurface plumbing on geothermal discharge

Namiki

Ueno

Hurwitz

et al. 2016

Geochem. Geophys. Geosyst.

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“…Hsieh et al observed different modes of flows including the steady flow (less than 150 kg/h), periodic flow of a medium amplitude (the peak value varied from 150 to 300 kg/h), periodic flow of large amplitude (the peak value was greater than 300 kg/hr), and chaotic flow depending on Q and Δ T sub . Marcel et al also reported geysering and flashing‐induced instability at low Q and low p loop in one and two‐parallel channels. They also found flashing‐induced oscillations having some characteristics of DWO.…”

Section: Introductionmentioning

confidence: 94%

Subcooled boiling oscillations in natural circulation boiling loop at low pressure

2013

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Flow instabilities in a natural circulation boiling loop at a low pressure are reported. The oscillations at boiling incipience are primarily chaotic and bifurcate to quasiperiodic ones depending on inlet subcooling ΔTsub and heater power Q. They also strongly depend on water volume Φ in the loop. We have presented power spectrums, attractor reconstructions, and Hurst exponents for the analysis of the experimental data. The analysis shows that the primary oscillations are very similar to geysering instability. Chaotic oscillations occur at low ΔTsub or high Q, whereas quasiperiodic oscillations occur at high ΔTsub or low Q. Our experiments also suggest that wall superheat exceeding a critical value triggers the instability. © 2013 American Institute of Chemical Engineers AIChE J, 60: 375–386, 2014

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“…Their phenomenon stems from a density difference between the inlet and outlet fluid states, which can trigger a delayed and alternating feedback from the subcooled liquid inertia and compressibility of the two-phase mixture, Figure 100. One characteristic of DWO is that the oscillation period is approximately 1.5 to 2 times of the fluid transit time in the channel [76]. Flow pattern transition instabilities have been postulated as occurring when the flow conditions are close to the point of transition between bubbly flow and annular flow.…”

Section: Instability Mechanismsmentioning

confidence: 99%

An Overview of Non-LWR Vessel Cooling Systems for Passive Decay Heat Removal (Technical Letter Final Report)

Lisowski¹,

Lv²,

Alexandreanu³

et al. 2021

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The following report provides a technical review of various reactor vessel cooling system (VCS) concepts under consideration for decay heat removal (DHR) in non-light water advanced reactor designs. This review focuses on ex-vessel designs, including the Reactor Cavity Cooling System (RCCS), the Reactor Vessel Auxiliary Cooling System (RVACS), and hybrid iterations, using both air and water cooling to achieve their heat removal function. Based on a literature review of publicly available sources published between 1979 and 2021, a technical summary is presented detailing existing and planned VCS design options, their applicability to specific reactor type, and review of authored research and development studies. Following an assessment of the availability of data and modeling tools, an evaluation was performed analyzing their likely performance during normal, degraded, and accident conditions, including reliability, stability, and longevity.With renewed consideration of air-based DHR systems by some US vendors, there is a need to fully understand the complexities inherent to natural circulation systems, and more importantly, how they may influence safety-related heat removal functions and system performance. For DHR systems that rely on air-based mode of cooling, this entails quantification of the impacts of low flow conditions during start-up, relative elevations of inlet and outlet ducts for below-grade installations, effects of the use of multiple parallel chimneys for redundancy, and impact of weather conditions at the plant site. For systems relying on water-based mode cooling, reliance on limited coolant inventory in an event of pipe break or extended duration accident scenarios, sensitivities related to stability of boiling flow and heat transfer conditions, and quantification of full-scale structural vibrations on balance of plant structures are among the complicating factors. Paperwork Reduction Act StatementThis report does not contain information collection requirements and, therefore, is not subject to the requirements of the Paperwork Reduction Act of 1995 (44 United States Code [U.S.C.] 3501 et seq.). Public Protection NotificationThe U.S. Nuclear Regulatory Commission (NRC) may not conduct or sponsor, and a person is not required to respond to, a request for information or an information collection requirement unless the requesting document displays a current valid Office of Management and Budget (OMB) control number.

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Experimental investigations on flashing-induced instabilities in one and two-parallel channels: A comparative study

Cited by 36 publications

References 18 publications

An experimental study of the role of subsurface plumbing on geothermal discharge

An experimental study of the role of subsurface plumbing on geothermal discharge

Subcooled boiling oscillations in natural circulation boiling loop at low pressure

An Overview of Non-LWR Vessel Cooling Systems for Passive Decay Heat Removal (Technical Letter Final Report)

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