Effect of inlet pressure and temperature on density wave oscillations in a horizontal channel

Dorao, Carlos Alberto

doi:10.1016/j.ces.2015.03.040

Cited by 19 publications

(5 citation statements)

References 24 publications

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“…Generally, in a two-phase flow system, density wave oscillations are due to the difference in the densities between the high-density liquid phase and the low-density vapor phase, and this can cause a sudden pressure drop or perturbation in the flow velocity, resulting in flow instability in the system [37]. However, the fluid density along the pseudocritical line can change rapidly even in a supercritical fluid, and this can also cause a phenomenon similar to density wave oscillation.…”

Section: Analysis Of the Instabilitymentioning

confidence: 99%

Instability Analysis of Supercritical CO2 during Transportation and Injection in Carbon Capture and Storage Systems

Min

Kang²,

Huh

2018

Energies

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Captured CO2 is in a subcritical state, whereas CO2 deep underground is in a supercritical state because of the high geothermal heat and pressure. The properties of CO2 can change rapidly at the critical point and in the near-critical region during the transportation and injection process. This study aims to identify the instabilities in the CO2 flow in these regions, along with the causes and effects, during the transportation and injection process, and propose relevant design specifications. Thus, the critical points and near-critical region of CO2 flow were numerically analyzed. The unstable region is presented in terms of temperature and pressure ranges, and the changes in the CO2 properties in this region were analyzed. In the unstable region, the sudden change in density was similar to the density wave oscillation of a two-phase flow. The CO2 stability map we obtained and the stability map of supercritical water show similar trends. Flow instability was also found to occur in standard CO2 transportation pipelines. We demonstrate that flow instability in CO2 transportation and injection systems can be avoided by maintaining the proposed conditions.

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Section: Analysis Of the Instabilitymentioning

confidence: 99%

Instability Analysis of Supercritical CO2 during Transportation and Injection in Carbon Capture and Storage Systems

Min

Kang²,

Huh

2018

Energies

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“…In the particular case of DWO, the period of the oscillations can be closer to twice the fluid transit time for low inlet subcooling and even longer at high inlet subcooling 15 . Research has been motivated by the need to understand the conditions for their occurrence [15][16][17][18] , the characteristics of the oscillations and parameters affecting them 13,18,19 , and in particular their effect on the heat transfer capability of the flow 10,11 . The latter has been a source of major debate and studies due to its impact on the operation of high heat flux systems.…”

mentioning

confidence: 99%

“…The temperature of the fluid is estimated based on the inlet conditions and by two internal thermocouples installed at these locations. Further details can be found in previous publications 10,17,19 and in the supplementary material. Heat transfer comparison.…”

mentioning

confidence: 99%

“…Note that the amplitude and period of pressure oscillations in a system strongly depend on the external configuration of the system [28][29][30] , namely the characteristics of the pump, valves, and the overall flow loop. In particular, the effect of the slope of the pump characteristic curve and the bypass on the amplitude of the oscillations is evident from previous research [28][29][30][31] . Therefore, this study concludes that the self-sustained oscillations when triggered by an external system with minimum pressure oscillations, i.e.…”

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confidence: 99%

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The overlooked role of pressure oscillations on heat transfer deterioration during self-sustained flow oscillations

Paul

Fernandino

Dorao

2020

Applied Physics Letters

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The naturally occurring oscillations during flow boiling inside a heated pipe under specific conditions are known to hinder the system performance. Although substantial research has been done to reveal the occurrence and control mechanisms of such oscillations, the heat transfer mechanism remains a puzzle to be solved. In particular, it is believed that the heat transfer deterioration can be attributed to the flow velocity variation, namely the amplitude and period of the oscillations. Here we show that the heat transfer deterioration does not necessarily depend on the flow velocity variation. Using controlled experiments we investigate the underlying mechanisms of the heat transfer deterioration during flow oscillations. We show that the associated pressure oscillations play a dominant role in triggering the heat transfer deterioration. In the absence of pressure oscillations, even a high amplitude flow velocity oscillation does not deteriorate the heat transfer rates in the studied conditions.

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“…For example, in previous studies, it is possible to observe that the amplitude of the superimposed density wave oscillation has been amplified about five to ten times. [9][10][11] Only a few studies have been focused on understanding the interplay of density wave and pressure drop oscillations. Briefly, a typical boiling system where two-phase flow oscillations may occur consists in a heated section, inlet and outlet valves (or orifice plates) is characterized by a compressible volume due to the presence of vapor in the system.…”

Section: Introductionmentioning

confidence: 99%

On the occurrence of superimposed density wave oscillations on pressure drop oscillations and the influence of a compressible volume

2018

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Although two-phase flow instabilities are attributed to be one of the impediments for achieving high heat flux in boiling systems, most of their fundamental characteristics remain uncharted. In particular, pressure drop oscillations and density wave oscillations are two types of dynamic two-phase flow instabilities that can cause large variations in pressure and temperature. Under particular working conditions, both oscillations have been observed to interact, resulting in long-period pressure drop oscillations with superimposed short-period density wave oscillations. However, in this situation, the amplitude of the density wave oscillations is typically larger than the corresponding to a pure density wave oscillation. Here, we show that a compressible volume in the system, essential for the occurrence of pressure drop oscillations, plays a major role in amplifying the amplitude of the superimposed density wave oscillations.

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Effect of inlet pressure and temperature on density wave oscillations in a horizontal channel

Cited by 19 publications

References 24 publications

Instability Analysis of Supercritical CO2 during Transportation and Injection in Carbon Capture and Storage Systems

Instability Analysis of Supercritical CO2 during Transportation and Injection in Carbon Capture and Storage Systems

The overlooked role of pressure oscillations on heat transfer deterioration during self-sustained flow oscillations

On the occurrence of superimposed density wave oscillations on pressure drop oscillations and the influence of a compressible volume

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