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  • Industrial Chemistry  (3)
  • refrigerants  (2)
  • R113  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 10 (1989), S. 701-712 
    ISSN: 1572-9567
    Keywords: gaseous mixtures ; R12 + R114 ; refrigerants ; R12 ; R113 ; R114 ; superheated and supercritical ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract New viscosity measurements for the gaseous and supercritical state of the halogenated hydrocarbons R12, R113, and R114 and binary mixtures of R12 + R114 of different compositions are presented. The measurements were carried out at superheated and supercritical temperatures from 30 to 200° C and in the pressure range from 1 to 80 bar. Viscosity was measured with an oscillating-disk viscometer and the data obtained are relative to the viscosity of nitrogen. The estimated accuracy of the measured results is ±0.6%. The results obtained show that, at subcritical temperatures, the pressure effect on viscosity is negative. This anomalous behaviour is investigated in detail in this work. At atmospheric pressure the viscosity of gas mixtures is almost a linear function of their composition. At high pressure, the residual viscosities η -η 0 of both the pure components and the mixtures were used to follow a single relationship versus the residual reduced density ρ r0.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 20 (1999), S. 777-790 
    ISSN: 1572-9567
    Keywords: gaseous ; R404A ; R407C ; R410A ; R507 ; refrigerants ; saturation ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This paper presents new measurements of the viscosity of gaseous R404A (52 wt% R143a, 44 wt% R125, 4 wt% R134a), R407C (23 wt% R32, 25 wt% R125, 52 wt% R143a), R410A (50 wt% R32, 50 wt% R125), and R507 (50 wt% R143a, 50 wt% R125). These mixtures are recommended as substitutes for the refrigerants R22, R502, and R13B1. Measurements were carried out in an oscillating-disk viscometer. The obtained values of the viscosity are relative to the viscosity of nitrogen. The experiments were performed at atmospheric pressure over the temperature range 297 to 403 K. and near the saturation line up to pressures of 0.6 P crit. The estimated uncertainty of the reported viscosities are ±0.5% for the viscosities at atmospheric pressure and ± 1% along the saturation line, being limited by the accuracy of the available vapor pressure and density data. The experimental viscosities at atmospheric pressure are employed to determine the intermolecular potential parameters, σ and ɛ, which provide the optimum representation of the data with the aid of the extended law of corresponding states developed by Kestin et al. A comparison of the experimental viscosity data with the values calculated by REFPROP, both at atmospheric pressure and along the saturation line, is presented.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Messungen in beheizten Siedewasserkreisläufen ergaben, daß bei hohen Wärmestromdichten unter gewissen thermo- und hydrodynamischen Bedingungen die Zweiphasenströmung instabil wird, d. h., daß aperiodische oder periodische Druck- und Mengenstromänderungen auftreten. Es wurde nun versucht, diese experimentellen Beobachtungen theoretisch zu erklären und in einem einfachen Gleichungssystem zu erfassen. Die Rechnung geht von der Kontinuitätsgleichung, der Impulsgleichung sowie der Energiebilanz aus und berücksichtigt die charakteristischen Merkmale der Siedewasserströmung, wie Zweiphasenreibung und Voreilgeschwindigkeit der Dampfblasen. Die strömungs- und schwingungstechnischen Einflüsse wesentlicher Bauelemente eines Siedewasserkreislaufes, z. B. der Umwälzpumpe mit ihrer Förderkennlinie, der Drosselstellen und der mit kompressiblem Dampf gefüllten Räume, sind in der Berechnung enthalten. Die Ergebnisse der Berechnung geben Auskunft über Erscheinungsformen der Instabilitäten sowie über den zeitlichen und örtlichen Druck-, Dichte- und Mengenstromverlauf im Siedewasserkanal.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 70 (1998), S. 1105-1106 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 40 (1968), S. 515-521 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Hohe Wärmestromdichten führen zu Dampfblasenbildung an der Heizfläche, obwohl die Kühlflüssigkeit im Mittel noch nicht die Sättigungstemperatur erreicht hat. Die Beschleunigung und erhöhte turbulente Reibung durch die Blasenbildung bedingen eine Vervielfachung des Druckabfalles im Kanal. Bei Untersuchungen dieses Druckabfalles wurden periodische Druckschwankungen hoher Energie beobachtet, deren Frequenz und Amplitude mit wachsenden Werten von Heizflächenbelastung und Unterkühlungsgrad zunehmen. Unter gewissen Voraussetzungen, zu denen wesentlich der Verlauf von Förder- und Widerstandskennlinie beiträgt, verursachen diese Druckstörungen Instabilitäten und Pulsationen in der Strömung.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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