CFD modelling of non-equilibrium condensation of CO2 within a supersonic nozzle using metastability approach

2021 ◽  
Vol 85 ◽  
pp. 103715
Author(s):  
Harrivin Vijayakumaran ◽  
Tamiru Alemu Lemma
Keyword(s):  
Supersonic Nozzle ◽  
Cfd Modelling ◽  
Non Equilibrium

Multi-Phase CFD Modelling of CO2 Releases From High-Pressure Pipelines

2016 ◽  
Author(s):  
Xiong Liu ◽  
Ajit Godbole ◽  
Cheng Lu ◽  
Bin Liu ◽  
Philip Venton
Keyword(s):  
High Pressure ◽  
Relaxation Time ◽  
Mass Transfer Rate ◽  
Source Strength ◽  
Cfd Model ◽  
British Petroleum ◽  
Cfd Modelling ◽  
Time Relaxation ◽  
Multi Phase ◽  
Non Equilibrium

An accurate prediction of the ‘source strength’ of CO2 released from high-pressure pipelines is of great importance for risk assessment, because this parameter determines the subsequent dispersion in the atmosphere. The widely used method is to employ a one-dimensional discharge model describing the conservation of mass, momentum and energy. The fluid is usually considered to remain at thermal and mechanical equilibrium during the depressurisation process, while the non-equilibrium liquid/vapour transition phenomena are ignored. Although efforts have been made to model non-equilibrium, two-phase CO2 depressurisation in recent years, possible improvement can be made by using a more precise Equation of State (EOS) and more detailed models. In this paper, a multi-phase Computational Fluid Dynamics (CFD) model is presented to simulate CO2 releases from high-pressure pipelines. A real gas EOS (GERG-2008) was incorporated into the CFD code. This enabled accurate modelling of the thermodynamic properties to achieve a more precise source strength estimate. The non-equilibrium liquid/vapour transition was modelled by introducing source terms for mass and latent heat. A ‘time relaxation factor’ was used to control the inter-phase mass transfer rate. The CFD model was validated against experimental results from the British Petroleum (BP) CO2 release trials. The optimum relaxation time (for the CO2 depressurisation cases tested) was obtained through simulations by varying the time relaxation factors and comparison with experimental data. In addition, the effect of the relaxation time on the source strength prediction is discussed.

scholarly journals CFD modelling of the condensation inside a Supersonic Nozzle: implementing customized wet-steam model in commercial codes

2017 ◽  
Vol 126 ◽  
pp. 34-41 ◽  
Author(s):  
Mazzelli Federico ◽  
Giacomelli Francesco ◽  
Milazzo Adriano
Keyword(s):  
Supersonic Nozzle ◽  
Wet Steam ◽  
Cfd Modelling

715 Non-Equilibrium Condensation in a Supersonic Nozzle Flow with Swirl

2013 ◽  
Vol 2013.66 (0) ◽  
pp. 227-228
Author(s):  
Shotaro SUETSUGU ◽  
Shigeru MATUO ◽  
Junji NAGAO ◽  
Yushiro NISHIYAMA ◽  
Toshiaki SETOGUCHI
Keyword(s):  
Supersonic Nozzle ◽  
Nozzle Flow ◽  
Non Equilibrium

Application of analytical electron microscopy to studies of equilibrium and non-equilibrium segregation in materials

1992 ◽  
Vol 50 (2) ◽  
pp. 1214-1215
Author(s):  
Edward A Kenik
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Extended Defects ◽  
Probe Diameter ◽  
Specimen Holder ◽  
Analytical Electron ◽  
Scanning Transmission ◽  
Solute Atoms ◽  
Equilibrium Segregation ◽  
Non Equilibrium

Segregation of solute atoms to grain boundaries, dislocations, and other extended defects can occur under thermal equilibrium or non-equilibrium conditions, such as quenching, irradiation, or precipitation. Generally, equilibrium segregation is narrow (near monolayer coverage at planar defects), whereas non-equilibrium segregation exhibits profiles of larger spatial extent, associated with diffusion of point defects or solute atoms. Analytical electron microscopy provides tools both to measure the segregation and to characterize the defect at which the segregation occurs. This is especially true of instruments that can achieve fine (<2 nm width), high current probes and as such, provide high spatial resolution analysis and characterization capability. Analysis was performed in a Philips EM400T/FEG operated in the scanning transmission mode with a probe diameter of <2 nm (FWTM). The instrument is equipped with EDAX 9100/70 energy dispersive X-ray spectrometry (EDXS) and Gatan 666 parallel detection electron energy loss spectrometry (PEELS) systems. A double-tilt, liquid-nitrogen-cooled specimen holder was employed for microanalysis in order to minimize contamination under the focussed spot.

Equilibrium and Non-Equilibrium Statistical Thermodynamics

2004 ◽  
Author(s):  
Michel Le Bellac ◽  
Fabrice Mortessagne ◽  
G. George Batrouni
Keyword(s):  
Statistical Thermodynamics ◽  
Non Equilibrium
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