Abstract: The status of the literature is reviewed for several thermophysical properties of pure solid and liquid tungsten which constitute input for the modelling of intense plasma-surface interaction phenomena that are important for fusion applications. Reliable experimental data are analyzed for the latent heat of fusion, the electrical resistivity, the specific isobaric heat capacity, the thermal conductivity and the mass density from the room temperature up to the boiling point of tungsten as well as for the surface tension and the dynamic viscosity across the liquid state. Analytical expressions of high accuracy are recommended for these thermophysical properties that involved a minimum degree of extrapolations. In particular, extrapolations were only required for the surface tension and viscosity.

Abstract: The thermodynamic properties of HFO-1336mzz(E) (trans-1,1,1,4,4,4-hexafluoro-2-butene) were determined. The critical point was ascertained by visual observation of the meniscus disappearance within an optical cell. The critical temperature, critical density, and critical pressure were determined to be 403.37 ± 0.03 K, 515.3 ± 5.0 kg m−3, and 2766.4 ± 4.5 kPa, respectively. Vapor pressures were also measured at temperatures ranging from 323 K (50 °C) to the critical temperature, and were correlated using the Wagner-type equation. The acentric factor and normal boiling point were determined to be 0.4053 and 280.58 K (7.43 °C), respectively, using the vapor pressure correlation. Based on the critical parameters and the acentric factor, saturated vapor densities and liquid densities were estimated using the Peng–Robinson equation and the Hankinson–Thomson equation, respectively. The heat of vaporization was also calculated from the Clausius–Clapeyron equation.

Abstract: This paper shows experimental results about R1234yf condensation inside a microfin tube with an inner diameter at the fin tip of 3.4 mm. R1234yf is a new environmentally friendly refrigerant, with a Global Warming Potential lower than 1, therefore it matches the new environmental laws. Experimental tests are carried out for mass velocities from 100 to 1000 kg m −2 s −1 , vapor qualities from 0.95 to 0.2, at saturation temperature of 30 °C and 40 °C. The experimental results show that heat transfer coefficient increases when both mass velocity and vapor quality increase. Frictional pressure gradient increases with mass velocity at constant vapor quality, whereas at constant mass velocity it increases with vapor quality up to a maximum, after which it slightly decreases. The experimental heat transfer coefficient and pressure drop are also compared against the values predicted by empirical correlations available in the open literature.

Abstract: Ionic liquids (ILs) have received much attention in the last two decades. One of the important applications is to use this relatively new class of compounds for the separation of azeotropic mixtures via extractive distillation. In this paper, overall extractive distillation processes of two azeotropic separation systems using a favorable ionic liquid as entrainer are rigorously developed. The optimized design flowsheets are compared with the conventional processes using an industrial entrainer. The two ionic liquid extractive distillation systems include separating acetone and methanol using 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP]) as entrainer and another system of separating isopropyl alcohol and water using 1-ethyl-3-methylimidazolium acetate ([EMIM][OAC]) as entrainer. The potential drawbacks of using an ionic liquid in the extractive distillation systems are given in the paper. It is found that the degradation temperature and high normal boiling point temperature of the ionic liquids i...

Abstract: Providing refrigeration at very low cryogenic temperatures requires the use of several stages of compression refrigeration with progressively lower boiling point refrigerants in the various stages. The cascade of cycles ultimately rejects heat to cooling water, but the working fluid at each stage removes heat from a lower-temperature source and rejects this heat plus the compressor work in that stage to a higher-temperature sink. The design of these systems appears to be only qualitatively discussed in the literature, and no discussion of their plantwide dynamic control has been found. This paper presents a quantitative design of a three-stage compression refrigeration process that uses methane, ethylene and propylene as the working refrigerant fluids in the three stages. Heat is removed in the condenser of a cryogenic distillation column separating carbon monoxide and methane. The bubble-point temperature of carbon monoxide at 13.9 bar is −158 °C. The distillation column condenser is cooled by evaporating boiling liquid methane at −163 °C. The second stage has an evaporator with boiling ethylene at −106.7 °C. The final stage has an evaporator with boiling propylene at −25.9 °C. An effective plantwide control structure is developed and tested.

Abstract: An experimental study was conducted on a 19.05 mm (outer diameter) dimpled enhanced tube to evaluate the in-tube two phase heat transfer and pressure drop performance in an annular section created between the enhanced tube and a solid round PVC rod. The purpose of the study was to understand the effect of forced early transition to annular flow on the pressure drop and heat transfer coefficient in a horizontal tube. The refrigerant studied was R-134a at a saturation temperature of 5 °C, heat flux range 2.5 to 15 kW m−2, mass flux from 80 to 200 kg m−2 s−1 and inlet vapor quality of 0.12 to 0.72. Flow pattern and pressure drop results were obtained under adiabatic conditions. Under similar operating conditions the enhanced tube with a rod exhibited three times higher heat transfer performance versus same size smooth empty tube with lower pressure drop penalty at lower mas flux.

Abstract: Hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs) are two of the most promising families of low-GWP fluids being investigated as alternatives for HFCs in HVAC&R applications. Within the HCFO family, trans-1-chloro-3,3,3-trifluoropropene (R1233zd(E)) is a compound with a relatively high normal boiling point temperature (∼291.1 K) and was developed primarily as a blowing agent for polymer foams, a low-pressure refrigerant for chiller applications, and a working fluid for low-temperature ORC applications. This article presents 81 vapor pressure data points measured over the temperature range from (234.15 to 375.15) K in two different laboratories. The data are fitted to Wagner-type and Antoine-type equations and compared to existing correlations and other published data.

Abstract: A transferable united-atom (UA) force field based on Mie potentials is presented for branched alkanes. The performance of the optimized Mie potential parameters is assessed for 32 branched isomers of butane, pentane, hexane, heptane, and octane using grand canonical histogram-reweighting Monte Carlo simulations. For each compound, vapor–liquid-coexistence curves, vapor pressures, heats of vaporization, critical properties, and normal boiling points are predicted and compared to experiment. Experimental saturated liquid densities and critical temperatures are reproduced with a median absolute average error of 0.6%, while vapor pressures are reproduced with a median absolute average error of 2.2%. Calculations performed with the TraPPE and NERD force fields produce median absolute average errors for saturated liquid densities and vapor pressures of 1.3–1.8% and 14.3–23.5%, respectively. Binary phase diagrams predicted by the Mie potentials for argon+neopentane, methane+neopentane, and ethane+isobutane are i...

Abstract: This study examines the experimental adiabatic two-phase frictional pressure drop of R134a in rectangular multiport minichannel with and without fins having 20 channels with hydraulic diameters of 0.64 mm and 0.81 mm, respectively. The pressure drop measurements were done under mass flux range of 50–200 kg m −2 s −1 , saturation temperature range of 20–35 °C, and inlet vapor quality range of 0.1–0.9. The effects of mass flux, saturation temperature, inlet vapor quality and channel geometry on frictional pressure drop were investigated. The results discovered that the mass flux, inlet vapor quality, saturation temperature and channel geometry play an important role in increasing or decreasing the frictional pressure drop. The present experimental data were compared with eleven existing well known frictional pressure drop correlation available in the open literature. In addition, a new two-phase frictional pressure drop correlation is proposed considering the effects of inertia, viscous force, fluid properties, channel geometry and surface tension and also validated the correlation with the available data.

Abstract: Pressure drop for propane and isobutane were performed in a horizontal small tube of stainless steel with 1.0 mm inner diameter. The tests were conducted at mass fluxes from 240 to 480 kg m −2 s −1 and heat fluxes from 5 to 60 kW m −2 at 25 °C saturation temperature. The effect of flow patterns, mass flux, vapour quality and heat flux are discussed. Strong influence of mass flux and vapour quality on pressure drop was found. The comparisons of experimental data with predicted value proposed by existing correlations available in literature for pressure drop are analyzed.

Abstract: In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor–liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius–Clapeyron relation. The couple velocity–pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.

Abstract: The flash point of hydrocarbons and petroleum mixtures is important safety-related data for processing and handling of these materials. In this paper, experimentally measured data on flash points of about 140 pure hydrocarbons and petroleum fractions were collected and used to evaluate existing methods for prediction of these data available in the literature. The errors for the available methods varied from 1.6 to 4.9% for pure hydrocarbons and from 3.7 to 11.1% for petroleum fractions. In these methods, parameters such as vapor pressure, boiling point, molecular weight, density, activity coefficient, and composition were used. On the basis of the available methods and simplified relations for vapor pressure prediction, it was found that the ratio of the flash point to the boiling point of hydrocarbon systems and their mixtures is a constant and a value of this constant is about 0.7 when both temperatures are expressed in absolute degrees. The average absolute deviation for this simplified method was 1.7%...

Abstract: Non-catalytic hydrogenation with a hydrogen donor is a beneficial way for effective conversion of asphaltene to distillate with minimal coke formation. In this work, detailed product distribution, which includes gas, light oil [initial boiling point (IBP)–350 °C], middle oil (350–540 °C), heavy oil (>540 °C), asphaltene, and coke, obtained from non-catalytic hydrogenation of asphaltene with tetralin as a hydrogen donor, was investigated in an autoclave. The effects of reaction conditions, including reaction time, reaction temperature, and hydrogen donor/asphaltene weight ratio, on asphaltene conversion, detailed product distribution, liquid product yield, and liquid product selectivity were studied. Results showed that through controlling the reaction condition, asphaltene conversion and total liquid yield reached 72.72 and 70.34 wt %, respectively, and produced only 2 wt % coke and 0.34 wt % gas. We then developed a seven-lump kinetic model, including an active hydrogen lump to describe the reaction beha...

Abstract: The extraction process with propane: butane = 3: 1 (by mass) mixture in the liquid and supercritical fluid states was used to extract petroleum products containing 12.05 mass % of anhydrous oil sludge as solid particulates. The extraction was carried out at 85–160°С and 5–50 MPa. The desired oil product contains 2.8 mass % of sulfur, it has a density of 880 kg/m3 and a kinematic viscosity of 73.75 mm2/s at 20°С as well as start and end boiling point values of 43.6 and 325°С, respectively.

Abstract: The thermodynamic properties of vanadium have been evaluated to 3700 K. Selected values include an enthalpy of sublimation of 515 ± 2 kJ/mol at 298.15 K and a boiling point at one atmosphere pressure of 3694 K.

Abstract: This article presents detailed two-phase diabatic pressure drop data for refrigerant R134a at a saturation pressure of 5.5 bar corresponding to the saturation temperature of 19.4 °C. Study cases have been set for a mass flux varying from 100 to 500 kg m −2 s −1 . The obtained data are used as a validation of the void fraction literature models, a set of graphs shows comparisons, for a representative set of experimental conditions, of the two-phase frictional pressure gradients for the adiabatic and diabatic flow. Verification of the acceleration pressure drop predictions for two-phase adiabatic flow showed that all correlations predict that over 60% of experimental data fit in the range of ±30%. The model proposed in this article predicts 63% of presented data within 10% error, and 96% of the data are predicted within 30% error.

Abstract: The upgrading of heavy oil from Karamay using supercritical methanol (SC-MeOH) as a solvent was studied in a batch reaction. Through orthogonal experiments, the effects of the temperature, mass ratio of methanol to oil, reaction time, and agitation speed were investigated. The optimal reaction conditions, depending on the boiling range of light products such as maltenes and the yields of byproducts such as asphaltenes, were as follows: reaction temperature of 350 °C, reaction time of 60 min, stirring agitation of 900 rpm, and mass ratio of methanol to oil of 1:1. A simultaneous increase agitation speed would significantly reduce the condensation behavior. Analysis of the simulated distillation of maltenes indicated that the components with boiling points lower than 380 °C increased from 19 wt % in the raw material to 38 wt % in the maltenes products. The viscosity of light products decreased to 24.1 mPa·s. The FTIR of asphaltene results showed that the temperature has contradictory influence on upgrading ...