Browse by Author "Hrnjak, P.S."

  • 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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  • Tallitsch, D.A.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2001-07)
    This investigation explored the effects of fractionation and distribution of R-407c in brazed plate evaporators with an emphasis at low mass flux. Experiments were performed in parallel with R-22. A parametric study was ...

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  • Hong, S.H.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1999-10)

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  • Nelson, S.M.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2002-01)

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  • Dane, M.H.; Miller, N.R.; Alleyne, Andrew G.; Bullard, C.W.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2002-08)

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  • McEnaney, R.P.; Yin, J.M.; Bullard, C.W.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1999-07)

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  • Winkler, C.M.; Vanka, S.P.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2002-10)
    In the current dissertation work, the preferential concentration and deposition of heavy solid particles in a downward, fully developed turbulent square duct flow are studied using large eddy simulations. A second-order ...

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  • Drozdek, J.C.; Chappell, J.D.; Cusano, C.; Hrnjak, P.S.; Miller, N.R.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2000-07)
    A study was performed on a swashplate compressor to determine the state of lubrication. Measurements of electrical resistance were taken as a primary measure of oil film lubrication at the sliding shoe/swashplate interface. ...

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  • Chappell, J.D.; Drozdek, J.C.; Cusano, C.; Hrnjak, P.S.; Miller, N.R.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2000-07)
    This study used previously developed instrumentation to determine the state of compressor lubrication in an automotive NC system during three transient tests. The primary technique used in the study was measurement of ...

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  • Drozdek, J.C.; Chappell, J.D.; Cusano, C.; Hrnjak, P.S.; Miller, N.R.; Newell, T.A. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2000-02)
    Understanding lubrication failures at the shoe/swash plate contact of automotive swash plate compressors will greatly enhance the reliability of the air conditioning system. Maintaining proper lubrication is not always ...

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  • Singh, G.M.; Rodarte, E.; Miller, N.R.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2000-04)
    This paper presents several modifications to the 1995 IEC standard model for predicting the aerodynamic noise generated by control valves in ideal gas. The modifications account for frictional pressure drop from the valve ...

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  • Mao, Y.; Terrell, Jr., W.J.; Reef, R.C.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1997-12)

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  • Singh, G.M.; Rodarte, E.; Miller, N.R.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 1999-07)

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  • Singh, G.M.; Rodarte, E.; Miller, N.R.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2000-04)
    A method is presented for predicting the noise generated by expansion devices throttling refrigerant, based on an existing standard model for predicting the noise downstream of large, industrial control valves throttling ...

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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 ...

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  • 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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  • 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)
    A first principles-based model was developed for a transcritical C02 gas cooler, using a finite element method. The model uses published correlations for refrigerant and airside heat transfer and pressure drop. Experimental ...

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  • Solberg, J.R.; Miller, N.R.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2000-02)
    A traditional method of controlling evaporator superheat in a vapor compression air conditioning system is the thermostatic expansion valve (TXV). Such systems are often used in automotive applications. The TXV depends ...

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  • Verma, P.; Bullard, C.W.; Hrnjak, P.S. (Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign., 2001-06)
    Factors affecting frost distribution are explored using a finite element model, developed and validated using a full-scale 8-row heat exchanger in a wind tunnel. The heat exchanger is typical of the type used in ...

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