Browse by Subject "pressure drop"

  • Park, C.Y.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2007-01)
    Carbon dioxide (CO2) has been seriously considered as an alternate refrigerant for HCFC and HFC fluids, due to the increasing interest of environmentally safe refrigerants in air-conditioning and refrigeration systems. ...
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  • Nino, V.G.; Hrnjak, P.S.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2002-10)
    Aluminum multi-port microchannel tubes are currently utilized in automotive air conditioners for refrigerant condensation. Recent research activities are directed toward developing other air conditioning and refrigeration ...
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  • Zilly, J.; Jang, J.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2003-03)
    Enhanced tubes have been commonly used in heat exchangers for 30 years. Modern micro-fin tubes play a significant role in high-efficiency refrigerators and air conditioners with their significantly enhanced heat ...
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  • Jang, J.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2004-06)
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  • Komandiwirya, H.B.; Hrnjak, P.S.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2005-04)
    Measurements of pressure drop and heat transfer coefficient were taken for smooth and internally enhanced smooth sections. Pure ammonia was used in both smooth and enhanced tubes, whereas ammonia mixed with oil only used ...
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  • Vollrath, J.E.; Hrnjak, P.S.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2003-10)
    Pressure drop and heat transfer measurements were taken for smooth and internally enhanced aluminum test sections using pure R22 and ammonia. Two-phase condensation tests were conducted in the horizontallyoriented test ...
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  • Zhang, Q.M.; Hrnjak, P.S.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2003-12)
    This project aims to find correlations between various flow parameters and liquid refrigerant flow distribution within a horizontal manifold supplying two-phase R134a downward into fifteen aluminum microchannels. Liquid ...
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  • Yoo, T.; Hrnjak, P.S.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2002-12)
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  • Tu, X.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2004-01)
    Fluid flow and heat transfer in microchannels are very important in various fields, including miniature thermal systems, compact heat exchangers and electronics cooling. The purpose of this investigation is to contribute to ...
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  • Nino, V.G.; Jassim, E.W.; Hrnjak, P.S.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2005-07)
    A flow-regime based pressure drop model is developed to correlate experimental data in the intermittent and annular flow regime. For the intermittent region, an alternative method for microchannel pressure drop predictions ...
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  • Meyer, J.J.; Dunn, W.E. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1996-08)
    This study examines the heat transfer and pressure drop performance of R22 and R502 alternatives, most of which are mixtures of two or three refrigerants, while condensing in an enhanced tube and while expanding in a ...
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  • Jassim, E.W.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2005-07)
    Probabilistic two-phase flow map pressure drop and void fraction models are developed for 6-port microchannels in order to provide a more accurate and common means of predicting void fraction and pressure drop. The models ...
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  • Adams, D.C.; Hrnjak, P.S.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2003-12)
    Aluminum multi-port microchannels are currently utilized in automotive air conditioners for refrigerant condensation. In general, research activities are directed towards developing other air conditioning and refrigerat ...
    untranslated PDF (426KB)
  • Yin, J.M.; Bullard, C.W.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2000-04)
    Single-phase pressure drops inside a microchannel heat exchanger were tested systematically. Local pressure drop coefficients were determined from the experimental data and compared with published correlations. Results ...
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  • Thompkins, D.M.; Newell, T.A.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2002-12)
    In Chapter 1, an experimental investigation of single phase fluid distribution through an array of microchannel discharge tubes was conducted. Span-wise pressure profiles were also obtained. The working fluids were air ...
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  • Wilson, M.J. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2001-05)
    The purpose of this study was to observe refrigerant behavior in flattened copper tubes. A round, smooth tube with an internal diameter of 8.91 mm is taken as the base case. This tube is then successively flattened to ...
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  • Payne, W.T. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2000-12)
    An experimental investigation of pressure drop and void fraction in aluminum microchannel tubes was conducted for a variety of flow conditions. Primary fluids of interest are refrigerants, R134a and R41OA. The microchannel ...
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