The Effects of Ambient Pressure on the Initiation of the Freezing Process for a Water Droplet on a Cold Surface

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Zheyan Jin ◽  
Yingpei Zhao ◽  
Dongyu Sui ◽  
Zhigang Yang
Keyword(s):  
Liquid Water ◽  
Water Droplet ◽  
Freezing Point ◽  
Ambient Pressure ◽  
Air Pressure ◽  
Bulk Liquid ◽  
Freezing Process ◽  
Common Belief ◽  
Cold Surface ◽  
Wide Range

This study investigated the effect of air pressure on the freezing process of a water droplet on a cold surface. A common belief is that bulk liquid water is incompressible and air pressure does not affect the freezing point of the bulk liquid water over a wide range of pressure. However, our results demonstrated that, for a water droplet on a cold surface, its freezing process started early at lower ambient pressures. Such a phenomenon can be explained by the effects of the evaporative cooling.

Contemporary Liquid Water on Mars?

2020 ◽  
Vol 49 (1) ◽  
Author(s):  
James J. Wray
Keyword(s):  
Liquid Water ◽  
Freezing Point ◽  
Active Surface ◽  
Annual Review ◽  
Publication Date ◽  
Pure Liquid ◽  
Martian Surface ◽  
Cold Surface ◽  
Ongoing Research ◽  
Recurring Slope Lineae

The martian surface preserves a record of aqueous fluids throughout the planet's history, but when, where, and even whether such fluids exist at the contemporary surface remains an area of ongoing research. Large water volumes remain on the planet today, but mostly bound in minerals or frozen in the subsurface, with limited direct evidence for aquifers. A role for water has been suggested to explain active surface processes monitored by orbital and landed spacecraft, such as gullies and slope streaks across a range of latitudes; however, dry mechanisms appear at least equally plausible for many active slopes. The low modern atmospheric density and cold surface temperatures challenge models for producing sufficient volumes of water to do the observed geomorphic work. The seeming ubiquity of salts in martian soils facilitates liquid stability but also has implications for the habitability of any such liquids. ▪ A thin modern atmosphere and low temperatures make pure liquid water unstable on the surface of modern Mars. ▪ Widespread salts could enhance liquid durability by lowering the freezing point and slowing evaporation. ▪ Dielectric measurements suggest active brines deep beneath the south pole and, in transient thin films, within shallow polar soils. ▪ Some characteristics of gullies, recurring slope lineae, and other active features challenge both current wet and dry formation models. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 49 is May 28, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Experimental and numerical study on the impact and freezing process of a water droplet on a cold surface

2018 ◽  
Vol 137 ◽  
pp. 83-92 ◽  
Author(s):  
Yina Yao ◽  
Cong Li ◽  
Zhenxiang Tao ◽  
Rui Yang ◽  
Hui Zhang
Keyword(s):  
Water Droplet ◽  
Numerical Study ◽  
Freezing Process ◽  
Cold Surface ◽  
The Impact

IMPROVED LUMPED-DIFFERENTIAL ANALYSIS OF THE FREEZING PROCESS IN A SUPERCOOLED WATER DROPLET

2020 ◽  
Author(s):  
Emerson Barbosa dos Anjos ◽  
Carolina Palma Naveira Cotta ◽  
Renato Machado Cotta ◽  
Igor Soares Carvalho ◽  
Manish Tiwari
Keyword(s):  
Water Droplet ◽  
Supercooled Water ◽  
Freezing Process ◽  
Differential Analysis

Numerical investigation of the impacting and freezing process of a single supercooled water droplet

2021 ◽  
Vol 33 (4) ◽  
pp. 042114
Author(s):  
Yongkui Wang ◽  
Lei Ju ◽  
Duanfeng Han ◽  
Qing Wang
Keyword(s):  
Numerical Investigation ◽  
Water Droplet ◽  
Supercooled Water ◽  
Freezing Process

Fuel Droplet Evaporation in a Supercritical Environment

2002 ◽  
Vol 124 (4) ◽  
pp. 762-770 ◽  
Author(s):  
G. S. Zhu ◽  
S. K. Aggarwal
Keyword(s):  
Experimental Data ◽  
Phase Equilibrium ◽  
Ambient Pressure ◽  
Droplet Surface ◽  
Fuel Vapor ◽  
Phase Solubility ◽  
Liquid Density ◽  
Ambient Temperatures ◽  
Droplet Vaporization ◽  
Wide Range

This paper reports a numerical investigation of the transcritical droplet vaporization phenomena. The simulation is based on the time-dependent conservation equations for liquid and gas phases, pressure-dependent variable thermophysical properties, and a detailed treatment of liquid-vapor phase equilibrium at the droplet surface. The numerical solution of the two-phase equations employs an arbitrary Eulerian-Lagrangian, explicit-implicit method with a dynamically adaptive mesh. Three different equations of state (EOS), namely the Redlich-Kwong (RK), the Peng-Robinson (PR), and Soave-Redlich-Kwong (SRK) EOS, are employed to represent phase equilibrium at the droplet surface. In addition, two different methods are used to determine the liquid density. Results indicate that the predictions of RK-EOS are significantly different from those obtained by using the RK-EOS and SRK-EOS. For the phase-equilibrium of n-heptane-nitrogen system, the RK-EOS predicts higher liquid-phase solubility of nitrogen, higher fuel vapor concentration, lower critical-mixing-state temperature, and lower enthalpy of vaporization. As a consequence, it significantly overpredicts droplet vaporization rates, and underpredicts droplet lifetimes compared to those predicted by PR and SRK-EOS. In contrast, predictions using the PR-EOS and SRK-EOS show excellent agreement with each other and with experimental data over a wide range of conditions. A detailed investigation of the transcritical droplet vaporization phenomena indicates that at low to moderate ambient temperatures, the droplet lifetime first increases and then decreases as the ambient pressure is increased. At high ambient temperatures, however, the droplet lifetime decreases monotonically with pressure. This behavior is in accord with the reported experimental data.

scholarly journals Bulk Liquid Water at Ambient Temperature and Pressure from MP2 Theory

2013 ◽  
Vol 4 (21) ◽  
pp. 3753-3759 ◽  
Author(s):  
Mauro Del Ben ◽  
Mandes Schönherr ◽  
Jürg Hutter ◽  
Joost VandeVondele
Keyword(s):  
Ambient Temperature ◽  
Liquid Water ◽  
Bulk Liquid ◽  
Temperature And Pressure

The petrological and geochemical study of granitoid rocks from Mashhad area, Iran: Evidence for the Late Triassic Collisional Belt Northeast of Iran

2021 ◽  
Author(s):  
Banafsheh Vahdati ◽  
Seyed Ahmad Mazaheri
Keyword(s):  
Subduction Zones ◽  
Tectonic Setting ◽  
Crustal Contamination ◽  
Oceanic Lithosphere ◽  
Late Triassic ◽  
Common Belief ◽  
Thrust Tectonics ◽  
Wide Range ◽  
Lree Enrichment ◽  
Granitoid Rocks

<p>Mashhad granitoid complex is part of the northern slope of the Binalood Structural Zone (BSZ), Northeast of Iran, which is composed of granitoids and metamorphic rocks. This research presents new petrological and geochemical whole-rock major and trace elements analyses in order to determine the origin of granitoid rocks from Mashhad area. Field and petrographic observations indicate that these granitoid rocks have a wide range of lithological compositions and they are categorized into intermediate to felsic intrusive rocks (SiO<sub>2</sub>: 57.62-74.39 Wt.%). Qartzdiorite, tonalite, granodiorite and monzogranite are common granitoids with intrusive pegmatite and aplitic dikes and veins intruding them. Based on geochemical analyses, the granitoid rocks are calc-alkaline in nature and they are mostly peraluminous. On geochemical variation diagrams (major and minor oxides versus silica) Na<sub>2</sub>O and K<sub>2</sub>O show a positive correlation with silica while Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, CaO, Fe<sub>2</sub>O<sub>3</sub>, and MgO show a negative trend. Therefore fractional crystallization played a considerable role in the evolution of Mashhad granitoids. Based on the spider diagrams, there are enrichments in LILE and depletion in HFSE. Low degrees of melting or crustal contamination may be responsible for LILE enrichment. Elements such as Pb, Sm, Dy and Rb are enriched, while Ba, Sr, Nd, Zr, P, Ti and Yb (in monzogranites) are all depleted. LREE enrichment and HREE depletion are observed in all samples on the Chondrite-normalized REE diagram. Similar trends may be evidence for the granitoids to have the same origin. Besides, LREE enrichment relative to HREE in some samples can indicate the presence of garnet in their source rock. Negative anomalies of Eu and Yb are observed in monzogranites. Our results show that Mashhad granitoid rocks are orogenic related and tectonic discrimination diagrams mostly indicate its syn-to-post collisional tectonic setting. No negative Nb anomaly compared with MORB seems to be an indication of non-subduction zone related magma formation. According to the theory of thrust tectonics of the Binalood region, the oceanic lithosphere of the Palo-Tethys has subducted under the Turan microplate. Since the Mashhad granitoid outcrops are settled on the Iranian plate, this is far from common belief that these granitoid rocks are related to the subduction zones and the continental arcs. The western Mashhad granitoids show more mafic characteristics and are possibly crystallized from a magma with sedimentary and igneous origin. Thus, Western granitoid outcrops in Mashhad are probably hybrid type and other granitoid rocks, S and SE Mashhad are S-type. Evidences suggest that these continental collision granitoid rocks are associated with the late stages of the collision between the Iranian and the Turan microplates during the Paleo-Tethys Ocean closure which occurred in the Late Triassic.</p>

Understanding Micro-Droplet Interface Bilayers for Developing Bioinspired Sensors

2013 ◽  
Author(s):  
Guru Venkatesan ◽  
Andy Sarles
Keyword(s):  
Water Droplet ◽  
Morphological Changes ◽  
High Surface ◽  
High Surface Area ◽  
Material System ◽  
Modes Of Operation ◽  
New Class ◽  
Wide Range ◽  
Droplet Sizes ◽  
The Stability

Droplet-based biomolecular arrays form the basis for a new class of bioinspired material system, whereby decreasing the sizes of the droplets and increasing the number of droplets can lead to higher functional density for the array. In this paper, we report on a non-microfluidic approach to form and connect nanoliter-to-femtoliter, lipid-coated aqueous droplets in oil to form micro-droplet interface bilayers (μDIBs). Two different modes of operation are reported for dispensing a wide range of droplet sizes (2–200μm radius). Due to the high surface-area-to-volume ratios of microdroplets at these length scales, droplet shrinking is prominent, which affects the stability and lifetime of the bilayer. To better quantify these effects, we measure the shrinkage rates for 8 different water droplet/oil compositions and study the effect of lipid placement and lipid type on morphological changes to μDIBs.

Plasma-Assisted Combustor Dynamics Control at Ambient and Realistic Gas Turbine Conditions

2017 ◽  
Author(s):  
Wookyung Kim ◽  
Jeffrey Cohen
Keyword(s):  
Gas Turbine ◽  
Ambient Pressure ◽  
Plasma Discharge ◽  
Inlet Temperature ◽  
Pulsed Plasma ◽  
Plasma Power ◽  
Lean Blowout ◽  
Wide Range ◽  
Baseline Temperature ◽  
Increasing Temperature

The central objective of this study is to investigate the effectiveness of implementing a plasma discharge to improve combustor dynamics and flame stability. Specifically, a nano-second pulsed plasma discharge (NSPD) was applied to a premixed gaseous fuel/air dump combustor for mitigation of dynamic combustion instabilities with a minimal NOX penalty. This paper addresses the scaling of this technology from ambient pressure and temperature conditions to more realistic gas turbine combustor conditions. A model combustor operating at representative conditions of O (102) m/s flow velocity, ∼ 580 K combustor inlet temperature, and ∼ 5 atm in-combustor pressure was selected to simulate a typical low-power environment of future aero engine gas turbine combustors. Fully premixed methane or propane was utilized as a fuel. Similar to a previous ambient-pressure study, a significant reduction of pressure fluctuation level was observed, by a factor of 2X to 4X over a wide range of velocity at the baseline temperature and pressure. The plasma power required for the reduction increased linearly with increasing velocity. The change of fuel from methane to propane showed that propane requires significantly (2X) higher plasma power to achieve a similar level of noise reduction. It was also observed that the lean blowout (LBO) limit was significantly extended in the presence of the plasma, however, substantial incomplete combustion occurs in the extended regime. NOX measurements showed that the incremental NOX production due to the presence of the plasma was low (∼ < 1EINOX) in general, however, it increased with decreasing velocity and pressure, and increasing temperature.

scholarly journals The faint young Sun problem revisited with a 3-D climate–carbon model – Part 1

2014 ◽  
Vol 10 (2) ◽  
pp. 697-713 ◽  
Author(s):  
G. Le Hir ◽  
Y. Teitler ◽  
F. Fluteau ◽  
Y. Donnadieu ◽  
P. Philippot
Keyword(s):  
Radiative Forcing ◽  
General Circulation ◽  
Freezing Point ◽  
Climatic Factors ◽  
General Circulation Models ◽  
Companion Paper ◽  
One Dimensional ◽  
Carbon Dioxide Concentrations ◽  
Wide Range ◽  
High Concentrations

Abstract. During the Archaean, the Sun's luminosity was 18 to 25% lower than the present day. One-dimensional radiative convective models (RCM) generally infer that high concentrations of greenhouse gases (CO2, CH4) are required to prevent the early Earth's surface temperature from dropping below the freezing point of liquid water and satisfying the faint young Sun paradox (FYSP, an Earth temperature at least as warm as today). Using a one-dimensional (1-D) model, it was proposed in 2010 that the association of a reduced albedo and less reflective clouds may have been responsible for the maintenance of a warm climate during the Archaean without requiring high concentrations of atmospheric CO2 (pCO2). More recently, 3-D climate simulations have been performed using atmospheric general circulation models (AGCM) and Earth system models of intermediate complexity (EMIC). These studies were able to solve the FYSP through a large range of carbon dioxide concentrations, from 0.6 bar with an EMIC to several millibars with AGCMs. To better understand this wide range in pCO2, we investigated the early Earth climate using an atmospheric GCM coupled to a slab ocean. Our simulations include the ice-albedo feedback and specific Archaean climatic factors such as a faster Earth rotation rate, high atmospheric concentrations of CO2 and/or CH4, a reduced continental surface, a saltier ocean, and different cloudiness. We estimated full glaciation thresholds for the early Archaean and quantified positive radiative forcing required to solve the FYSP. We also demonstrated why RCM and EMIC tend to overestimate greenhouse gas concentrations required to avoid full glaciations or solve the FYSP. Carbon cycle–climate interplays and conditions for sustaining pCO2 will be discussed in a companion paper.

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