scholarly journals 3D computer model of the Co-Cu-CoS-Cu2S subsystem T-x-y diagram above 800°C

2021 ◽  
pp. 28-28
Author(s):  
V.I. Lutsyk ◽  
V.P. Vorob'eva ◽  
A.E. Zelenaya ◽  
M.V. Lamueva
Keyword(s):  
Liquid Phase ◽  
Computer Model ◽  
Three Dimensional ◽  
Solidus Surface ◽  
Liquid Immiscibility ◽  
Phase Region ◽  
Binary Subsystem ◽  
Two Phase ◽  
Univariant Curve ◽  
3D Computer Model

The three-dimensional computer model of the Co-Cu-CoS-Cu2S subsystem T-x-y diagram at temperatures above 800oC is represented. It is shown that the liquid immiscibility in the binary subsystem Cu-Cu2S is transformed within the ternary system with Co into the wide two-phase region of two immiscible melts, which interrupts the univariant curve of the Co and Cu2S co-crystallization. The special features of the structure of the solidus surface of cobalt, caused by liquid-phase immiscibility are considered.

scholarly journals Thermodynamics and Machine Learning Based Approaches for Vapor–Liquid–Liquid Phase Equilibria in n-Octane/Water, as a Naphtha–Water Surrogate in Water Blends

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 413
Author(s):  
Sandra Lopez-Zamora ◽  
Jeonghoon Kong ◽  
Salvador Escobedo ◽  
Hugo de Lasa
Keyword(s):  
Machine Learning ◽  
Liquid Phase ◽  
Phase Equilibria ◽  
Aspen Plus ◽  
Phase Region ◽  
Two Phase ◽  
Technical Literature ◽  
Phase Liquid ◽  
Liquid Vapor ◽  
Vapor Liquid

The prediction of phase equilibria for hydrocarbon/water blends in separators, is a subject of considerable importance for chemical processes. Despite its relevance, there are still pending questions. Among them, is the prediction of the correct number of phases. While a stability analysis using the Gibbs Free Energy of mixing and the NRTL model, provide a good understanding with calculation issues, when using HYSYS V9 and Aspen Plus V9 software, this shows that significant phase equilibrium uncertainties still exist. To clarify these matters, n-octane and water blends, are good surrogates of naphtha/water mixtures. Runs were developed in a CREC vapor–liquid (VL_ Cell operated with octane–water mixtures under dynamic conditions and used to establish the two-phase (liquid–vapor) and three phase (liquid–liquid–vapor) domains. Results obtained demonstrate that the two phase region (full solubility in the liquid phase) of n-octane in water at 100 °C is in the 10-4 mol fraction range, and it is larger than the 10-5 mol fraction predicted by Aspen Plus and the 10-7 mol fraction reported in the technical literature. Furthermore, and to provide an effective and accurate method for predicting the number of phases, a machine learning (ML) technique was implemented and successfully demonstrated, in the present study.

Modeling of the Onset of Gas Entrainment Through a Finite-Side Branch

2003 ◽  
Vol 125 (5) ◽  
pp. 902-909 ◽  
Author(s):  
M. Ahmed ◽  
I. Hassan ◽  
N. Esmail
Keyword(s):  
Froude Number ◽  
Three Dimensional ◽  
Phase Region ◽  
Side Branch ◽  
Critical Height ◽  
Two Phase ◽  
Gas Entrainment ◽  
Branch Model ◽  
Predicted Values ◽  
New Criterion

A theoretical investigation has been conducted for the prediction of the critical height at the onset of gas entrainment during single discharge from a stratified, two-phase region through a side branch with a finite diameter. Two different models have been developed, a simplified point-sink model and a three-dimensional finite-branch model. The two models are based on a new criterion for the onset of gas entrainment. The results of the predicted critical heights at the onset of gas entrainment showed that the finite-branch model approaches the physical limits at low Froude numbers. However, as the values of the Froude number increased, the predictions of both models eventually converged to the same value. Based on the results of the models, the critical height corresponding to the onset of gas entrainment was found to be a function of Froude number and fluid densities. The results of both models are compared with available experimental data. The comparisons illustrate a very good agreement between the measured and predicted values.

The admissibility domain of rarefaction shock waves in the near-critical vapour–liquid equilibrium region of pure typical fluids

2016 ◽  
Vol 795 ◽  
pp. 241-261 ◽  
Author(s):  
Nawin R. Nannan ◽  
Corrado Sirianni ◽  
Tiemo Mathijssen ◽  
Alberto Guardone ◽  
Piero Colonna
Keyword(s):  
Shock Waves ◽  
Critical Point ◽  
Compressible Flows ◽  
Three Dimensional ◽  
Fundamental Equation ◽  
Phase Region ◽  
Liquid Equilibrium ◽  
Two Phase ◽  
Rarefaction Shock ◽  
Equilibrium Region

Application of the scaled fundamental equation of state of Balfour et al. (Phys. Lett. A, vol. 65, 1978, pp. 223–225) based upon universal critical exponents, demonstrates that there exists a bounded thermodynamic domain, located within the vapour–liquid equilibrium region and close to the critical point, featuring so-called negative nonlinearity. As a consequence, rarefaction shock waves with phase transition are physically admissible in a limited two-phase region in the close proximity of the liquid–vapour critical point. The boundaries of the admissibility region of rarefaction shock waves are identified from first-principle conservation laws governing compressible flows, complemented with the scaled fundamental equations. The exemplary substances considered here are methane, ethylene and carbon dioxide. Nonetheless, the results are arguably valid in the near-critical state of any common fluid, namely any fluid whose molecular interactions are governed by short-range forces conforming to three-dimensional Ising-like systems, including, e.g. water. Computed results yield experimentally feasible admissible rarefaction shock waves generating a drop in pressure from 1 to 6 bar and pre-shock Mach numbers exceeding 1.5.

Theoretical Analysis of the Onset of Gas Entrainment from a Stratified Two-Phase Region Through Two Side-Oriented Branches Mounted on a Vertical Wall

2005 ◽  
Vol 128 (1) ◽  
pp. 131-141 ◽  
Author(s):  
Mahmoud A. Ahmed
Keyword(s):  
Theoretical Analysis ◽  
Small Deviation ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Phase Region ◽  
Critical Height ◽  
Two Phase ◽  
Mass Rate ◽  
Gas Entrainment ◽  
Branch Model

A theoretical analysis has been developed to predict the critical height and the location of the onset of gas entrainment during discharge from a stratified two-phase region through two oriented-side branches mounted on a vertical wall. In this analysis, a point sink model was first developed, followed by a more accurate three-dimensional finite branch model. The models are based on a new modified criterion for the onset of gas entrainment. The theoretically predicted critical height and the location of the onset of gas entrainment are found to be a function of the mass rate of each branch (Fr1 and Fr2), the distance between the centerlines of the two branches (L∕d), and the inclination angle (θ). The effects of these variables on the predicted critical height and the onset location were investigated. Furthermore, comparison between the theoretically predicted results and the available experimental data was carried out to verify the developed models. The comparison shows that the predicted results are very close to the measured data within a deviation percentage of 12% at Fr1>10. This small deviation percentage reflects a good agreement between the measured and predicted results.

Three-Dimensional Integrated Circuit With Embedded Microfluidic Cooling: Technology, Thermal Performance, and Electrical Implications

2016 ◽  
Vol 138 (1) ◽  
Author(s):  
Xuchen Zhang ◽  
Xuefei Han ◽  
Thomas E. Sarvey ◽  
Craig E. Green ◽  
Peter A. Kottke ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Integrated Circuit ◽  
Single Phase ◽  
Three Dimensional ◽  
Phase Region ◽  
Heat Sinks ◽  
Thermal Testing ◽  
Two Phase ◽  
Maximum Heat ◽  
Maximum Heat Transfer

This paper reports on novel thermal testbeds with embedded micropin-fin heat sinks that were designed and microfabricated in silicon. Two micropin-fin arrays were presented, each with a nominal pin height of 200 μm and pin diameters of 90 μm and 30 μm. Single-phase and two-phase thermal testing of the micropin-fin array heat sinks were performed using de-ionized (DI) water as the coolant. The tested mass flow rate was 0.001 kg/s, and heat flux ranged from 30 W/cm2 to 470 W/cm2. The maximum heat transfer coefficient reached was 60 kW/m2 K. The results obtained from the two testbeds were compared and analyzed, showing that density of the micropin-fins has a significant impact on thermal performance. The convective thermal resistance in the single-phase region was calculated and fitted to an empirical model. The model was then used to explore the tradeoff between the electrical and thermal performance in heat sink design.

On sCO2 Compressor Performance Maps at Variable Intake Thermodynamic Conditions

2021 ◽  
Author(s):  
Alessandro Romei ◽  
Paolo Gaetani ◽  
Giacomo Persico
Keyword(s):  
Mach Number ◽  
Three Dimensional ◽  
Phase Region ◽  
Flow Coefficient ◽  
Two Phase ◽  
Dimensionless Parameters ◽  
Thermodynamic Conditions ◽  
Scaling Parameters ◽  
Compressor Performance ◽  
Carbon Dioxide Co2

Abstract Unconventional aero-thermodynamic phenomena affect the performance of compressors that operate with carbon dioxide (CO2) close to its thermodynamic critical point. As a consequence, whether compressor performance maps based on conventional scaling parameters, such as flow coefficient and peripheral Mach number, still posses general features remains an open question. In this work, we show that additional dimensionless parameters are needed to ensure full similarity conditions when intake thermodynamic conditions vary. Thanks to a combination of three-dimensional turbulent flow simulations, analytical developments and physical flow considerations, three main phenomena are shown to affect compressor operation when changing the upstream total state: (i) non-ideal effects that can modify the fluid compressibility from liquid-like to gas-like and vice versa, (ii) the extent of the two-phase region within the blade channel, (iii) the resulting compressibility of the two-phase mixture. Three dimensionless parameters are introduced to separately account for these effects and their relationship is highlighted. The influence of these parameters on compressor performance maps is widely discussed, shedding light on the way they act in the modification of the ideal similarity based only on the flow coefficient and the peripheral Mach number. As a general result, two additional dimensionless parameters are needed to guarantee similarity conditions in presence of non-ideal flows of CO2 subject to phase change. These findings are expected to be relevant for the plant regulation in off-design conditions and for planning experimental campaigns at different thermodynamic conditions.

The Prediction of Two-Phase Turbulence and Phase Distribution Phenomena Using a Reynolds Stress Model

1990 ◽  
Vol 112 (1) ◽  
pp. 107-113 ◽  
Author(s):  
M. Lopez de Bertodano ◽  
S.-J. Lee ◽  
R. T. Lahey ◽  
D. A. Drew
Keyword(s):  
Liquid Phase ◽  
Reynolds Stress ◽  
Lift Force ◽  
Phase Distribution ◽  
Liquid Velocity ◽  
Fluid Model ◽  
Three Dimensional ◽  
Reynolds Stress Model ◽  
Two Phase ◽  
Two Fluid Model

The void fraction distribution for turbulent bubbly air/water upflows and downflows in a pipe was analyzed using a three-dimensional two-fluid model. A τ − ε (i.e., Reynolds stress) turbulence model was used for the continuous (liquid) phase. The τ − ε transport equations yield all components of the Reynolds stress tensor for the liquid phase momentum equations. The effect of these stresses is to create a lateral pressure gradient that acts on the bubbles and effects their distribution. The lateral lift force on the bubbles has also been modelled. This lift force arises due to the relative motion of the bubble with respect to a nonuniform liquid velocity field. It has been observed experimentally that for upflows the bubbles concentrate near the wall while for downflows they move toward the center of the conduit. The model presented herein predicts these trends.

scholarly journals Thermodynamic Research on the Precipitation of Ti2O3, TiN and TiC in Continuous Casting of Titanium Microalloyed Steel

2021 ◽  
Vol 2076 (1) ◽  
pp. 012077
Author(s):  
Tengfei Zhao ◽  
Xiang Zheng ◽  
Dongjian Huang ◽  
Zhenghai Zhu ◽  
Zhihong Yin
Keyword(s):  
Liquid Phase ◽  
Continuous Casting ◽  
Microalloyed Steel ◽  
Phase Region ◽  
Second Phase ◽  
Two Phase ◽  
Initial Stage ◽  
Different Temperatures ◽  
C And N ◽  
Solid Liquid

Abstract The composite precipitation of Ti2O3 + TiN during continuous casting has an important influence on the microstructure and properties of the slab. In order to study the precipitation conditions of Ti2O3, TiN and TiC second phase in titanium microalloyed steel, the solid-liquid phase line temperature, the initial precipitation temperature of different second phase, the equilibrium and actual solubility product of Ti2O3, TiN and TiC at different temperatures are calculated, and the precipitation rules of titanium microalloyed steel in liquid steel and two-phase region are analyzed. The results show that: Ti2O3 and TiN can precipitate in molten steel, and the precipitation order of Ti2O3 is prior to that of TiN, while TiC does not precipitate. Due to the enrichment of Ti, O, C and N in the liquid phase during solidification, the equilibrium precipitation conditions of Ti2O3 and TiN are reached when the temperature is lower than 1469°C of the liquidus, and the precipitation begins at the initial stage of solidification. When the temperature in the two-phase region is lower than 1332°C, the precipitation of TiC begins.

scholarly journals 3D computer model of the Ag-Cu-Ni T-x-y diagram: verification of sections in the atlas of phase diagrams for lead-free soldering

2021 ◽  
Vol 57 (1) ◽  
pp. 15-24
Author(s):  
M. D. Parfenova ◽  
V. P. Vorob'eva ◽  
V. I. Lutsyk
Keyword(s):  
Phase Diagram ◽  
Ternary System ◽  
Phase Diagrams ◽  
Computer Model ◽  
Binary Systems ◽  
Three Dimensional ◽  
Lead Free ◽  
Published Data ◽  
Isothermal Sections ◽  
3D Computer Model

Spatial (three-dimensional - 3D) computer model of the T-x-y diagram of the Ag - Cu - Ni system, which is promising for the development of environmentally friendly solders, is presented. The model is constructed on the basis of published data on the binary systems forming this ternary system, the concentration projection of the liquidus surfaces, and four isothermal sections. It is shown that the phase diagram (PD) consists of 14 surfaces and 9 phase regions. The adequacy of the model is confirmed by comparing the isothermal sections and the liquidus projection.

The Effect of Temperature on Water Cavitation Phenomena in Converging-Diverging Nozzle Flow

2017 ◽  
Author(s):  
Zayed Ahmed ◽  
B. Terry Beck ◽  
Mohammad H. Hosni
Keyword(s):  
Liquid Phase ◽  
Vapor Pressure ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
New Technology ◽  
Phase Region ◽  
Operating Conditions ◽  
Working Fluid ◽  
Absolute Pressure ◽  
Two Phase

A vapor-compression refrigeration cycle typically uses standard refrigerants as the working fluid. Traditional refrigerants, however, have been associated with Ozone level Depletion Potential (ODP) and significant Global Warming Potential (GWP). An innovative cooling technology has been investigated using sonic multi-phase flow in a critical-flow nozzle to create a low-pressure and low-temperature region for heat absorption. The strength of the new technology is its potential to produce cooling using water and/or other working fluids with low ODP and GWP. While the full potential for using water as the working fluid may not be fully-realized, because of property limitations still under investigation, water still provides a very useful media for investigating the underlying cavitation phenomena for the development of the new technology. As part of ongoing research into the potential cooling capacity of the cavitation phenomena, cavitation in a converging-diverging nozzle is being investigated using water as the working fluid. Cavitation in a fluid is the formation of the vapor phase from the liquid phase by reduction in the pressure of the fluid below its saturated vapor pressure. Due to the constricting nature of the throat of a converging-diverging nozzle, the liquid water velocity at the throat is increased and the local absolute pressure can drop to values below the saturated vapor pressure of water at a given temperature; thus, causing the fluid to cavitate. The effect of water temperature on both the onset of the cavitation within the nozzle, and the resulting length of the cavitation region within the nozzle, are the subject of the current paper. Flow Visualization using a high speed digital camera under these different operating conditions was aimed at investigating the region of cavitation onset, which also appears to be associated with the region of boundary layer separation just downstream of the throat of the nozzle. The length of the two phase region at different operating temperatures was measured and it was observed that as the temperature of the fluid was increased, the length of two-phase region before it condensed into single-phase liquid became longer. Experimental results and analysis are presented which also show that near the onset of cavitation, the flowrate can likely go well beyond a choking condition without cavitating, and can remain in this metastable state for an extended amount of time before nucleating (cavitating) into a stable state. In particular, analysis indicates that significantly negative absolute pressures can likely be achieved within the nozzle, suggesting the presence of tension in the liquid phase just prior to cavitation.

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