Thermodynamic study of mixtures containing dibromomethane

Matteoli, Enrico; Lepori, Luciano; Porcedda, Silvia

doi:10.1007/s10973-017-6929-5

Cited by 3 publications

(2 citation statements)

References 27 publications

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“…Therefore, a prediction method suitable for viscosity of gas-liquid two-phase mixture must be proposed. As the initial filling pressure p 0 and temperature T 0 of the two-phase equilibrium system are given, the thermodynamic state of nitrogen and fire extinguishing agent can be ascertained based on the Gibbs phase rule [25][26][27].…”

Section: Average Viscositymentioning

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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Section: Average Viscositymentioning

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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“…Fig. 2 The thermodynamic equilibrium at gas-liquid interface for infinite bubble radius From the theory of gas-liquid phase equilibrium [36,37], the fugacity of nitrogen and agent are equal at both sides of the bubble.…”

Section: Fig the Schematic Diagram Of Release Process [9]mentioning

confidence: 99%

Prediction of the release process of the nitrogen-extinguishant binary mixture considering surface tension

Liu

Xie

Chen

et al. 2020

J Therm Anal Calorim

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Nitrogen used for pressurization in the extinguisher can be partially dissolved in the fire extinguishing agent. Consequently, the evolution of the dissolved nitrogen has a significant effect on the release behavior of the fire extinguishing agent in a rapid process. In this article, a new model was developed to predict the critical pressure of the nitrogen evolution and the release process of the fire extinguishing agent was described in detail. According to the Peng-Robinson (PR) equation of state and van der Waals mixing rule, the effect of the dissolved nitrogen on the surface tension of the fire extinguishant was analyzed by considering surface phase and fugacity coefficient. A method to calculate the surface tension of the liquid agent dissolved with nitrogen was proposed. The results showed that the proposed model can determine the accurate critical pressure of the evolution of the dissolved nitrogen and further evaluated whether nitrogen escapes. At different initial filling pressure, in addition, the release process of the nitrogen-extinguishant such as CF3I, FC218 (C3F8), HFC125 (C2HF5), and Halon1301 (CF3Br) was well predicted by the fluid release model when taking the surface tension and adiabatic index of the mixture into account. Compared with the previously obtained experimental data, the predictions obtained indicated that the present model can adequately describe the liquid and the gas mixture release stage in the release process of the nitrogenextinguishant.

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