Two-Phase Flow Analyses During Throttling Processes

Vacek, V.; Vinš, Václav

doi:10.1007/s10765-009-0589-z

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…Capillary tube CAP 2 assures continuous flow regime of SCP even when other parts of the CO2 branch or eventually of entire MPD are closed or under transient flow conditions. Pressure in the high-pressure line is measured with pressure transducer (6). Temperature and pressure of CO2 can be varied with the help of two stainless steel capillary tubes CAP 3 and CAP 4 submerged in a thermostatic bath (7) with liquid water.…”

Section: Co2 Branchmentioning

confidence: 99%

Investigation of droplet nucleation in CCS relevant systems: Progress in the design and testing of the mixture preparation device

et al. 2019

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The study presents progress in the development of mixture preparation device (MPD) representing an important part of the larger experimental setup intended for investigation of homogeneous droplet nucleation in CO2-rich systems. MPD allows for accurate adjustment of flow parameters, i.e. temperature, pressure, and flow rate, of CO2 in either superheated vapor or supercritical fluid phases and of other gas components such as argon or nitrogen. Through accurate settings of flow rates of individual components, the mixture composition can continuously be defined. MPD is going to be connected to the expansion chamber, where the droplet nucleation will experimentally be observed. In this work, CO2-branch, i.e. the core part of MPD, was modified and tested. Several components, e.g., pressure transducers and safety valve, had to be calibrated and adjusted to assure well-defined and safe operation. Most attention was paid to the design and performance of throttling capillary tubes installed in thermostatic bath, which define final flow parameters of CO2 coming from the CO2 branch. The flow characteristics of two capillary tubes with lengths of 7.8 and 4.0 m and inner diameter 0.1 mm were measured and compared to the predictions of a numerical model. The 1-D model of isothermal capillary flow was found to provide quite good agreement with the measured data.

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Section: Co2 Branchmentioning

confidence: 99%

Investigation of droplet nucleation in CCS relevant systems: Progress in the design and testing of the mixture preparation device

et al. 2019

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“…The two-phase flow of vapor-liquid mixture within an adiabatic capillary tube was predicted by the numerical model similar to that employed in our previous studies [8][9][10]. More details about the design of the capillary tubes and the flow behavior of CO 2 at various inlet and outlet conditions will be provided in other article.…”

Section: Capillary Tubes On Co2 Branchmentioning

confidence: 99%

“…Another option is to replace the current capillary tubes CAP 3 and CAP 4 with another capillary tubes having the same dimensions and to verify the results measured in this study. The inner diameter can significantly vary along the capillary tube length [9,10].…”

Section: Preliminary Testsmentioning

confidence: 99%

Investigation of droplet nucleation in CCS relevant systems – Design and testing of a CO₂ branch of the mixture preparation device

et al. 2017

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Abstract.A unique in-house designed experimental apparatus for investigation of nucleation of droplets in CCS relevant systems is being developed by our team. The nucleation is measured with the help of a rapid pressure drop within an expansion chamber. In this study, a CO2 branch representing an important part of the mixture preparation device (MPD) was designed, assembled and tested. MPD is intended for preparation of CO2-rich mixtures in a sense of accurate setting of flow rates of individual gaseous components through the experimental section with the expansion chamber. In the CO2 branch, the saturated liquid CO2 coming from a cylinder with a dip tube is pressurized by a supercritical pump with a constant flow rate to the pressures of up to 340 bar. The required mass flow of the supercritical CO2 of up to 180 g/h at pressures between 74 bar and 150 bar is accurately tuned with a help of a set of stainless steel capillary tubes with inner diameter of 0.1 mm. Some of the tubes are submerged in a thermostatic bath set to a constant temperature of 70 °C in order to assure the supercritical flow conditions of CO2. Needed lengths of the capillary tubes were determined with a help of a one-dimensional numerical model allowing prediction of both isothermal and adiabatic flow conditions.

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“…Kemal et al[7] built a one-dimensional flow experiment platform for fire extinguishing agent, including HFC227ea, HFC125, water, and CO2, and finally developed a one-dimensional flow calculation module (FSP) for fire extinguishing agent by using RELAP5 software. In addition, Vacek and Vins[8] measured mass data of adiabatic throttling experiments on pure FC218 and N2 + FC218 in horizontal pipes, based on which, a twophase critical mass flow rate prediction model was established including the unstable region of superheated liquid and two-phase flow. Moreover, Vacek et al[9] carried out more in-depth adiabatic throttling experiments on the FC218 dissolved nitrogen, and found that the existence of nitrogen made the starting position of the two-phase flow significantly earlier than that of pure FC218, leading to the decrease of the mass flow rate through the capillary.…”

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confidence: 99%

Prediction of steady-state two-phase flow of nitrogen + extinguishant in the pipeline and a correlation for mass flow rate

Liu

Xie

Chen

et al. 2021

J Therm Anal Calorim

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Nitrogen used for pressurization of a fire extinguisher could be partially dissolved in the fire extinguishing agent, forming a binary mixture accompanied by a phase change while flowing inside the pipeline. Notwithstanding the widespread use of fire extinguishing system, an effective method has never been considered to predict two-phase flow performance of nitrogen + extinguishant in the pipeline. This paper presents investigation of the steady-state two-phase flow of extinguishant in the pipeline, including C3HF7 (HFC227ea), CF3I, and C2HF5 (HFC125). The average viscosity of mixture was calculated using six quoted methods (VM-1 to VM-6).Subsequently, inspired by one-dimensional adiabatic isenthalpic flow of refrigerant in a capillary tube, the corresponding prediction models (STFM-1 to STFM-6) for large mass flux nitrogen + extinguishant in a fire extinguishing pipeline were developed based on the VM-1 to VM-6. In comparison with previous experimental and theoretical data, the applicability and accuracy of the proposed mathematical models was examined from two different aspects, mass flow rate and pressure drop. The results indicated that both models, STFM-2 and STFM-3, predicted accurately for mass flow rate, and STFM-2 model predicted accurately for pressure drop. Finally, new correlations for mass flow rate and pressure drop have been established accurately based on summarizing the relevant predicted data, respectively. This work contributes to a good theoretical approach on the analysis of two-phase flow of nitrogen + extinguishant. Keywords: steady-state two-phase flow; adiabatic isenthalpic expansion; average viscosity; mass flow rate; pressure drop Nomenclature T' presumptive temperature r' parameter of the PRμ model defined in Eq. (5) p pressure, Pa μ dynamic viscosity, 10 -7 Pa•s

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Two-Phase Flow Analyses During Throttling Processes

Cited by 5 publications

References 17 publications

Investigation of droplet nucleation in CCS relevant systems: Progress in the design and testing of the mixture preparation device

Investigation of droplet nucleation in CCS relevant systems: Progress in the design and testing of the mixture preparation device

Investigation of droplet nucleation in CCS relevant systems – Design and testing of a CO₂ branch of the mixture preparation device

Prediction of steady-state two-phase flow of nitrogen + extinguishant in the pipeline and a correlation for mass flow rate

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Two-Phase Flow Analyses During Throttling Processes

Cited by 5 publications

References 17 publications

Investigation of droplet nucleation in CCS relevant systems: Progress in the design and testing of the mixture preparation device

Investigation of droplet nucleation in CCS relevant systems: Progress in the design and testing of the mixture preparation device

Investigation of droplet nucleation in CCS relevant systems – Design and testing of a CO2 branch of the mixture preparation device

Prediction of steady-state two-phase flow of nitrogen + extinguishant in the pipeline and a correlation for mass flow rate

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Investigation of droplet nucleation in CCS relevant systems – Design and testing of a CO₂ branch of the mixture preparation device