Surface Tension of Supercooled Water: No Inflection Point down to −25 °C

Hrubý, Jan; Vinš, Václav; Mareš, Radim; Hykl, Jiří; Kalová, Jana

doi:10.1021/jz402571a

Cited by 75 publications

(114 citation statements)

References 22 publications

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“…The surface tension of water under both stable and metastable supercooled state evaluated from equation (2) is shown in figure 8. Preliminary data agree relatively well with the IAPWS correlation (1) extrapolated to subzero temperatures and consequently also to our previous results obtained with the capillary elevation method [9,10]. The estimated standard combined uncertainty of the measured surface tension is approximately 1.5 times higher than for previous measurements (around ± 0.40 mN m -1 at -4 °C in [9]) as it increases from ± 0.59 mN m -1 at + 40 °C to ± 0.63 mN m -1 at 7 C −°.…”

Section: Resultssupporting

confidence: 91%

“…The surface tension increasing with decreasing temperature changes its slope approximately at a temperature of -8 °C. This anomaly, referred as the second inflection point in the temperature course of the surface tension of pure water, has been recently refuted by new measurements performed by our group [9]. The measuring technique was based on a modified capillary elevation method using a vertical capillary tube placed partly in a temperature-controlled chamber [10].…”

Section: Introductionmentioning

confidence: 99%

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An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

Vinš

Hošek

Hykl

et al. 2015

EPJ Web of Conferences

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Abstract. New experimental apparatus for measurement of the surface tension of liquids under the metastable supercooled state has been designed and assembled in the study. The measuring technique is similar to the method employed by P.T. Hacker [NACA TN 2510] in 1951. A short liquid thread of the liquid sample was sucked inside a horizontal capillary tube partly placed in a temperature-controlled glass chamber. One end of the capillary tube was connected to a setup with inert gas which allowed for precise tuning of the gas overpressure in order of hundreds of Pa. The open end of the capillary tube was precisely grinded and polished before the measurement in order to assure planarity and perpendicularity of the outer surface. The liquid meniscus at the open end was illuminated by a laser beam and observed by a digital camera. Application of an increasing overpressure of the inert gas at the inner meniscus of the liquid thread caused variation of the outer meniscus such that it gradually changed from concave to flat and subsequently convex shape. The surface tension at the temperature of the inner meniscus could be evaluated from the overpressure corresponding to exactly planar outer meniscus. Detailed description of the new setup together with results of the preliminary tests is provided in the study.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

Vinš

Hošek

Hykl

et al. 2015

EPJ Web of Conferences

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“…Figure 7 shows the deviation of the counterpressure data and the literature data from the extrapolated IAWPS correlation (eq 2). A systematic deviation of Hacker's data 14 from both the new data and the extrapolated IAPWS correlation is clearly visible at 26 The temperature trend of the measured surface tension supports the previous study 16 refuting the existence of SIP, expected in the temperature range from −9 to +30°C, or any other anomaly in the surface tension of supercooled water. On the other hand, a small systematic offset of the new data from the extrapolated correlation (eq 2) is observed at temperatures below −17°C.…”

Section: The Journal Of Physical Chemistry Bsupporting

confidence: 82%

“…In this study, new data sets verifying our previous measurements 16,29 were collected. The Prague setup was modified such that it could be used for two slightly different measuring techniques: a classical capillary rise method (height technique) with improved accuracy and a new approach based on the counterpressure capillary rise method (counterpressure technique).…”

Section: ■ Introductionmentioning

confidence: 98%

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Surface Tension of Supercooled Water Determined by Using a Counterpressure Capillary Rise Method

et al. 2015

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Measurements of the surface tension of supercooled water down to −25°C have been reported recently (Hrubýet al. J. Phys. Chem. Lett. 2014, 5, 425−428). These experiments did not show any anomalous temperature dependence of the surface tension of supercooled water reported by some earlier measurements and molecular simulations. In the present work, this finding is confirmed using a counterpressure capillary rise method (the counterpressure method) as well as through the use of the classical capillary rise method (the height method). In the counterpressure method, the liquid meniscus inside the vertical capillary tube was kept at a fixed position with an in-house developed helium distribution setup. A preset counterpressure was applied to the liquid meniscus when its temperature changed from a reference temperature (30°C) to the temperature of interest. The magnitude of the counterpressure was adjusted such that the meniscus remained at the same height, thus compensating the change of the surface tension. One advantage of the counterpressure method over the height method consists of avoiding the uncertainty due to a possible variation of the capillary diameter along its length. A second advantage is that the equilibration time due to the capillary flow of the highly viscous supercooled water can be shortened. For both the counterpressure method and the height method, the actual results are relative values of surface tension with respect to the surface tension of water at the reference temperature. The combined relative standard uncertainty of the relative surface tensions is less than or equal to 0.18%. The new data between −26 and +30°C lie close to the IAPWS correlation for the surface tension of ordinary water extrapolated below 0.01°C and do not exhibit any anomalous features. ■ INTRODUCTIONThe surface tension of supercooled liquids, in particular, water and aqueous mixtures, is an important property both in academia and in industry. It plays an essential role in atmospheric research of the nucleation and growth of water droplets 1 and ice crystals. 2 It is known that water in clouds can persist in a supercooled liquid form at temperatures down to −38°C. 3 Manka et al. 4 recently showed that liquid water nanodroplets rather than ice crystals form by homogeneous nucleation at temperatures down to −73°C. Reliable data for the surface tension of supercooled aqueous systems are also important in technical applications such as operation of wind turbines, 5 aircraft icing, 6 or design of secondary refrigeration systems operating with brine. 7 Compared to other fluids, water shows several anomalies at low temperatures, e.g., the well-known maximum in the liquid density at +4°C at atmospheric pressure. The unusual behavior of liquid water becomes more distinct in the metastable supercooled region below 0°C. For instance, the isobaric heat capacity and the isothermal compressibility seemingly diverge (or approach a sharp maximum) when extrapolated to temperatures around −45°C, i.e., below the homogeneous nuc...

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Positive streamer initiation from raindrops in thundercloud fields

Babich¹,

Bochkov²,

Kutsyk³

et al. 2016

JGR Atmospheres

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The threshold field for the electric gas discharge in air is ≈26 kVcm−1atm−1, yet the maximum field measured (from balloons) is ≈3 kVcm−1atm−1. The question of how lightning is stimulated is therefore one of the outstanding problems in atmospheric electricity. According to the popular idea first suggested by Loeb and developed further by Phelps, lightning can be initiated from streamers developed in the enhanced electric field around hydrometeors. In our paper, we prove by numerical simulations that positive streamers are initiated, specifically, around charged water drops. The simulation model includes the kinetics of free electrons, and positive and negative ions, the electron impact ionization and photon ionization of the neutral atmospheric constituents, and the formation of space charge electric fields. Simulations were conducted at air pressure 0.4 atm, typical at thundercloud altitudes, and at different background electric fields, drop sizes, and charges. We show that the avalanche‐to‐streamer transition is possible near drops carrying 63–485 pC in thundercloud fields with intensity of 10 kVcm−1atm−1 and 15 kVcm−1atm−1 for drops sizes of 1 mm and 0.5 mm, respectively. Thus, the electric field required for the streamer formation is larger than the measured thunderstorm fields. Therefore, the results of simulations suggest that second mechanisms must operate to amplify the local field. Such mechanisms could be electric field space variations via collective effects of many hydrometeors or runaway breakdown.

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Surface Tension of Supercooled Water: No Inflection Point down to −25 °C

Cited by 75 publications

References 22 publications

An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

Surface Tension of Supercooled Water Determined by Using a Counterpressure Capillary Rise Method

Positive streamer initiation from raindrops in thundercloud fields

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