scholarly journals Two-Phase and Vapor-Phase Thermophysical Property (pvTz) Measurements of the Difluoromethane + trans-1,3,3,3-Tetrafluoroprop-1-ene Binary System

2020 ◽  
Vol 65 (4) ◽  
pp. 1554-1564 ◽  
Author(s):  
Sebastiano Tomassetti ◽  
Uthpala A. Perera ◽  
Giovanni Di Nicola ◽  
Mariano Pierantozzi ◽  
Yukihiro Higashi ◽  
...  
Keyword(s):  
Binary System ◽  
Thermophysical Property ◽  
Vapor Phase ◽  
Two Phase

scholarly journals Two-Phase and Vapor Phase PvTx Properties of the Difluoromethane + cis-1,3,3,3-Tetrafluoroprop-1-ene Binary System

2020 ◽  
Vol 65 (9) ◽  
pp. 4326-4334
Author(s):  
Sebastiano Tomassetti ◽  
Giovanni Di Nicola ◽  
Mariano Pierantozzi ◽  
J. Steven Brown
Keyword(s):  
Binary System ◽  
Vapor Phase ◽  
Two Phase ◽  
Pvtx Properties

scholarly journals Anatomy of the massive star-forming region S106

2018 ◽  
Vol 617 ◽  
pp. A45 ◽  
Author(s):  
N. Schneider ◽  
M. Röllig ◽  
R. Simon ◽  
H. Wiesemeyer ◽  
A. Gusdorf ◽  
...  
Keyword(s):  
Binary System ◽  
High Velocity ◽  
Central Area ◽  
Line Emission ◽  
Two Phase ◽  
Star Forming ◽  
Projected Length ◽  
Molecular Lines ◽  
Dark Lane ◽  
Gas Accretion

The central area (40″  × 40″) of the bipolar nebula S106 was mapped in the [O I] line at 63.2 μm (4.74 THz) with high angular (6″) and spectral (0.24 MHz) resolution, using the GREAT heterodyne receiver on board SOFIA. The spatial and spectral emission distribution of [O I] is compared to emission in the CO 16 →15, [C II] 158 μm, and CO 11 →10 lines, mm-molecular lines, and continuum. The [O I] emission is composed of several velocity components in the range from –30 to 25 km s−1. The high-velocity blue- and red-shifted emission (v = −30 to –9 km s−1 and 8 to 25 km s−1) can be explained as arising from accelerated photodissociated gas associated with a dark lane close to the massive binary system S106 IR, and from shocks caused by the stellar wind and/or a disk–envelope interaction. At velocities from –9 to –4 km s−1 and from 0.5 to 8 km s−1 line wings are observed in most of the lines that we attribute to cooling in photodissociation regions (PDRs) created by the ionizing radiation impinging on the cavity walls. The velocity range from –4 to 0.5 km s−1 is dominated by emission from the clumpy molecular cloud, and the [O I], [C II], and high-J CO lines are excited in PDRs on clump surfaces that are illuminated by the central stars. Modelling the line emission in the different velocity ranges with the KOSMA-τ code constrains a radiation field χ of a few times 104 and densities n of a few times 104 cm−3. Considering self-absorption of the [O I] line results in higher densities (up to 106 cm−3) only for the gas component seen at high blue- and red velocities. We thus confirm the scenario found in other studies that the emission of these lines can be explained by a two-phase PDR, but attribute the high-density gas to the high-velocity component only. The dark lane has a mass of ~275 M⊙ and shows a velocity difference of ~1.4 km s−1 along its projected length of ~1 pc, determined from H13CO+ 1 →0 mapping. Its nature depends on the geometry and can be interpreted as a massive accretion flow (infall rate of ~2.5 × 10−4 M⊙ yr−1), or the remains of it, linked to S106 IR/FIR. The most likely explanation is that the binary system is at a stage of its evolution where gas accretion is counteracted by the stellar winds and radiation, leading to the very complex observed spatial and kinematic emission distribution of the various tracers.

Influence of Compressed Carbon Dioxide on the Oxidation of Cyclohexane with Hydrogen Peroxide in Acetic Acid

2006 ◽  
Vol 59 (3) ◽  
pp. 225 ◽  
Author(s):  
Liang Gao ◽  
Tao Jiang ◽  
Buxing Han ◽  
Baoning Zong ◽  
Xiaoxin Zhang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Binary System ◽  
Reaction System ◽  
Phase Region ◽  
Phase Behaviour ◽  
Phase System ◽  
Two Phase ◽  
Three Phase

The oxidation of cyclohexane with H2O2 in a compressed CO2/acetic acid binary system was studied at 60.0 and 80.0°C, at pressures up to 18 MPa, and with the zeolite TS-1 as catalyst. The phase behaviour of the reaction system was also observed. There are three fluid phases in the reaction system at lower pressure but two at higher pressures. In the three-phase region the yields of the products, cyclohexanol and cyclohexanone, increase considerably with increasing pressure and reaches a maximum near the phase-separating pressure. CO2 can thus enhance the reaction effectively. However, the effect of pressure on the yield is very limited after the transition to a two-phase system.

Pressure Drop in a Capillary Tube in Boiling Two-Phase Flow

2003 ◽  
Author(s):  
Fumito Kaminaga ◽  
Baduge Sumith ◽  
Kunihito Matsumura
Keyword(s):  
Pressure Drop ◽  
Vapor Phase ◽  
Mass Flux ◽  
Two Phase Flow ◽  
Capillary Tube ◽  
Flow Boiling ◽  
Phase Flow ◽  
Two Phase ◽  
System Pressure ◽  
Phase Pressure

Two-phase pressure drop is experimentally examined in a flow boiling condition in a tube of diameter 1.45 mm using water in ranges of pressure from 10 to 100 kPa, mass flux from 18 to 152 kg/m2s, heat flux from 13 to 646 kW/m2, and exit quality from 0.02 to 0.77. Also, pressure drop in an adiabatic air-water two-phase flow is measured at atmospheric pressure using the same test section and mass flux ranges of liquid and gas as those in the flow boiling. Decreasing system pressure the pressure drop significantly increases at a given mass flux. Influence of vapor phase on the pressure drop is found to be large both in the adiabatic and the diabatic conditions. The frictional pressure drop correlation for the adiabatic two-phase flow is developed and applied to predict pressure drop in the flow boiling. But it cannot give satisfactory predictions. The Chisholm correlation calculating a two-phase pressure drop multiplier is modified to account the influence of vapor phase in a capillary tube and the modified correlation can predict the pressure drop in the flow boiling within an error of 20%.

Numerical study on evaporation heat transfer characteristics of water in inclined microchannels with varying inlet vapor quality

2019 ◽  
Vol 16 (1) ◽  
pp. 125-131
Author(s):  
Vivekanand SVB ◽  
Raju VRK
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Vapor Phase ◽  
Heated Wall ◽  
Phase Flow ◽  
Vapor Quality ◽  
Heat Transfer Characteristics ◽  
Two Phase ◽  
Ansys Fluent ◽  
Content Type

PurposeThe purpose of this paper is to investigate the effects of gravity on the heat transfer behavior of the two-phase flow of water undergoing phase change. Most of the earlier studies of convective boiling considered systems where the gravity is neglected. In contrast, the authors investigated systems where the gravity is considered. The heat transfer characteristics of water during its evaporation in microchannel heat sink are studied for different channel inclinations.Design/methodology/approachComputational fluid dynamics software ANSYS Fluent is used for the computational study. The volume of fluids multiphase method available in the package is used to capture the vapor–liquid interface. Heat transfer studies are carried out for a rectangular microchannel having a characteristic dimension of 825 µm at different inclinations, which varied from −90° (vertically downward) to 90° (vertically upward). During each simulation, the vapor quality is set at the inlet. Uniform heat flux of 250 kW/m2is applied at the bottom wall of the channel in all orientations of the channel, keeping the upper wall insulated.FindingsAs compared to horizontal configuration, a significant increase in the values of heat transfer coefficient during the fluid flow in inclined microchannels is noticed. It is observed that the Nusselt number for the vertically upward (+90°) and horizontal (0°) configuration are similar and that for the 45° upward configuration exceeds other configurations. It is also observed that the heat transfer performance becomes lower in downward configurations; nearly 40-50 per cent drop in average Nusselt number is observed for a mass flux of 250 kg m-2s-1with respect to 45° inclined microchannel. This behavior can be attributed to the gravitational effect on the two-phase flow because of which the vapor phase being less dense moves away from the heated wall, whereas the primary phase being heavier moves towards the heated wall of the channel. Also, the conductivity of the liquid being higher than the vapor phase, as well as the aperture of the liquid being small during this process, its velocity increases resulting in the augmentation of heat transfer.Originality/valueUser-defined-functions for the mass and energy source terms have been written in C code and hooked in ANSYS Fluent to incorporate the phase change mechanism during the evaporation of water.

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