A defnition of near-critical region based on heat capacity variation in transcritical heat exchangers

• Autorzy: Trela M. , Kwidziński R. , Butrymowicz D.
• Języki publikacji: EN

Abstrakty

EN

In the paper, a method for determination of the near-critical region boundary is proposed. The boundary is evaluated with respect to variations of specific heat capacity along isobars. It is assumed that the value of specific heat capacity inside the near-critical region exceeds by more than 50% the practically constant value typical for fluids under normal conditions. It appears that large variations of heat capacity are also present for high-pressure subcritical states sufficiently close to the critical point. Therefore, such defined near-critical region is located not only in supercritical fluid domain but also extends into subcritical fluid. As an example, the boundaries of the near-critical region were evaluated for water, carbon dioxide and R143a.

Słowa kluczowe

EN

critical thermodynamic state; heat transfer; near-critical region; speci.c heat capacity

PL

krytyczny stan termodynamiczny; obszar około-krytyczny; pojemność cieplna; wymiana ciepła

• Wydawca: Wydawnictwo Instytutu Maszyn Przepływowych PAN ; Komitet Termodynamiki i Spalania PAN
• Czasopismo: Archives of Thermodynamics
• Rocznik: 2011
• Tom: Vol. 32, no. 2
• Strony: 55--68
• Opis fizyczny: Bibliogr. 7 poz.,

Twórcy

autor

Trela M.

autor

Kwidziński R.

autor

Butrymowicz D.

• The Szewalski Institute of Fluid-Flow Machinery of the Polish Academy of Sciences, ul. Fiszera 14, 80-931 Gdańsk, Poland,

Bibliografia

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• [3] Angielczyk W., Butrymowicz D., Bartosiewicz Y., Dudar A.: Analysis of transcritical CO2 refrigeration cycle with two-phase ejector. In: Proc. 5th International Conference on Transport Phenomena In Multiphase Systems (HEAT 2008), Vol. 2, June 30–July 3, 2008, Białystok, Poland, 403–410.
• [4] Polyakov A.F.: Heat transfer under supercritical pressures. In: Advances in Heat Transfer, Vol. 21, (J.P. Hartnett et al., Eds.), Academic Press Inc., San Diego CA 1991, 1–53.
• [5] Y.-Y. Hsu, R.W. Graham: Transport Processes in Boiling and Two-Phase Systems. Including Near-Critical Fluids. Hemisphere Publ. Corp., Washington DC 1976.
• [6] Kurganov V.A.: Heat Transfer and Pressure Drop in Tubes under Supercritical Pressure of the Coolant. Part 1: Specifics of the Thermophysical Properties, Hydrodynamics and Heat Transfer of the Liquid. Regimes of Normal Heat Transfer. Thermal Engineering (English translation of Teploenergetika) 45(1998), 3, 177–185.
• [7] REFPROP – Reference Fluid Thermodynamic and Transport Properties, Ver. 8.0. National Institute of Standards and Technology (NIST), Boulder CO, 2007.