Report on the Final Results of ASHRAE RP-1767 Transport Properties of Moist Air

Transcription

1 Report on the Final Results of ASHRAE RP-767 Transport Properties of Moist Air S. Herrmann, H.-J. Kretzschmar (Zittau/Görlitz University of Applied Sciences, Zittau, Germany), V.C. Aute (University of Maryland, College Park, MD, USA), D.P. Gatley (Atlanta, GA, USA), E. Vogel (University of Rostock, Germany) Contents. Introduction. Recent Transport Properties Research 3. Algorithms for Moist Air Transport Properties 4. Deliverables of ASHRAE RP Conclusion and Outlook 8 ASHRAE Winter Conference, Chicago, IL, USA, nd of January, 8. Introduction State of the art: only two imprecise figures of transport properties of moist air, based on outdated equations, available in the current ASHRAE Handbook Ch. No ASHRAE Research Project was carried out on Transport Properties Research before RP-767 ASHRAE funded RP-485 Thermodynamic Properties of Moist Air, Dry Air, Steam, Water, and Ice, finished in 9 -> Gold Standard in Thermodynamics of Moist Air -> needed for the calculation of transport properties of moist air Extensive research on transport properties of dry air at NIST (4) IAPWS sponsored significant research on transport properties of water and steam in the period from 984 to 4 An unsolicited research proposal was written and submitted in 5 by S. Herrmann, H.-J. Kretzschmar, V.C. Aute, and D.P. Gatley Proposal was reviewed, accepted and PMC was installed ASHRAE RP-767 started on st of July, 6, and will last up to 3 st of December, 7; Update: an extension to the 3 th of June, 8 was requested S

2 . Recent Transport Properties Research New correlations for the viscosity and the thermal conductivity of dry air were published by Lemmon and Jacobsen (4) A new correlation for viscosity of H O were released as International Standard by IAPWS (8) based on research by Huber et al. at NIST A new correlation for thermal conductivity of H O were released as International Standard by IAPWS () based on research by Huber et al. at NIST Revised correlations for thermodynamic properties of moist air were developed within the ASHRAE Research Project RP-485 (Herrmann et al., 9) Vesovic-Wakeham procedure to model viscosity and thermal conductivity for mixtures (989, 99) Significant advancement in measuring moist air transport properties at higher pressures and temperatures resulting from research typical of the Compressed Air Energy Storage (CAES) process (final model can be used from 43 K to K and pressures to 4 MPa), European Union Project AA-CAES (-6) S 3 3. Algorithms for Moist Air Transport Properties Calculation of Viscosity of Moist Air Viscosity of gas mixures (Vesovic and Wakeham, 989) H HN Y H HN ( T,, x) mix m mix HN HNN YN HN HNN Y YN with N m j Yi xi xjijijm j mi mj H ii N i ii xx i j ij mm i j 4m j j ij 3 m i A ij mi mj i ji x xx mm 4 Hij Aij i j 3 i j ij i j Aijij mi mj N N m xx i j ij ij ij i j 6 5 mix 5 6 A ij S 4

3 Contact value of the pseudo-radial distribution function for a pure component i m ii i i m ii i mii i mii i mii i( T, m) i( T, m) with α ii from and, mii i( T, m) i( T, m) i m T / m and m as switch-over density Mixing rules 6 /3 /3 N /3 i j N xk k 5 k ij xk k 5 /3 k i j /3 /3 3 8 ij ii jj /3 S 5 Calculation of Thermal Conductivity of Moist Air Thermal Conductivity of gas mixures (Vesovic and Wakeham, 99) ( T,, x) (mon)( T,, x) (int)( T,, x) mix m mix m mix m Monatomic (mon) contribution Internal (int) contribution N (mon) N (mon) mix (int)(, m, ) i i xj ij ii i A T x i ii jxiij (mon) iiaij ji L L N Y L L N (mon)( T,, x) mix m mix LN LNN YN LN LNN Y YN S 6

4 N mm i j Yi xi x jijijm j mi mj L m m m B mm A x N i ii xx i jij 5 5 ii 3 4 i j j ij i j ij (mon) j (mon) 4 i Aijij mi mj ji xx mm 55 L 3 B 4 A i j i j ij i j ij ij ij Aij (mon) 4 ij mi mj and N N mm i j m xx i j ij ij ij ij mi mj 6 mix (mon) c m (mon) (mon) V i i, Mi o o 5 c m (mon) (mon) V ij ij Mij S 7 Contact value of the pseudo-radial distribution function for a pure component i ( T, m) with γ ii from i i( T, m) i( T, m) and, miii (mon) i (mon) m T m Mixing rules and /3 as switch-over density 6 /3 /3 N /3 i j N xk k 5 k ij xk k 5 /3 k i j /3 /3 3 8 ij ii jj i m ii (mon) i i m ii (mon) i i miii miii miii i( T, m) (mon) (mon) (mon) m / / S 8

5 Implementation of Vesovic-Wakeham Mixing Models for Moist Air Treatment of critical enhancement for pure components C i T m i,total T m i T m (, ) (, ) (, ) C i T m i,total T m i T m (, ) (, ) (, ) critical enhancement subtracted from total value for pure fluid -> performed for water only, since dry air far away from critical point C mix,total T m mix T m w T m,w (, ) (, ) (, ) critical enhancement for thermal conductivity of water added after mixing Calculation of water as hypothetical fluid water could become a liquid under pressure and temperature of moist air -> treated as hypothetical fluid for (T<T c ) and (ρ m >ρ ms ) as follows ( T, ) ( T, ) ( T, ) ( T, ) w m w ms w ref m w ref ms ( T, ) ( T, ) ( T, ) ( T, ) w m w ms w ref m w ref ms with T ref = 65 K and ρ ms as saturated vapor molar density at given temperature S 9 Quantities for interaction of unlike molecules based on extended corresponding states principle scaling factors resulting for pure components of dry air and water with following mixing rules: / ij ii jj ij ii jj ij ij kb.356 nm and / 76.8 K interaction viscosity in the limit of zero density follows from MM i.357 M M ij ( T ) ( ) i ijs Tij j j T / with 4 ij k ij k ln S ( T ) a ln T and are to be., each k and T ij kb T ij S

6 Improvement of Vesovic-Wakeham Model Using Experimental Data Adjustment of length scaling factor molecules of dry air and water do not correspond to spherically symmetric interaction potentials -> theorem of corresponding states inappropriate for interaction viscosity in the limit of zero densiy interaction viscosity now treated as function of mole fraction of water fitted to experimental data by Kestin and Whitelaw as well as by Hochrainer and Munczak resulting in adj ij n k w ij k k ( x ) x x b ( x x ) where coefficients b k adjusted with n = S Result of Improvement of Vesovic-Wakeham Model Using Experimental Data Kestin and Whitelaw (964): viscosity of moist air at atmospheric pressure S

7 4. Deliverables of ASHRAE RP Deliverable : New SI and I-P moist air property tables New SI and I-P moist air property tables for the ASHRAE Handbook of Fundamentals, Psychrometrics Chapter S 3 Old Figure of the current ASHRAE Handbook of Fundamentals, Psychrometrics Chapter, showing viscosity values for moist air Regions below red lines are the liquid and ice fog regions. Liquid fog Mixture model is needed to calculate viscosity in this region! Ice fog S 4

8 4. Deliverable : New Figures for Transport Properties of Moist Air New Figure for the ASHRAE Handbook of Fundamentals, Psychrometrics Chapter, showing viscosity values for moist air S 5 Old Figure 3 of the current ASHRAE Handbook of Fundamentals, Psychrometrics Chapter, showing thermal conductivity values for moist air Regions below red lines are the liquid and ice fog regions. Liquid fog Mixture model is needed to calculate thermal conductivity in this region! Ice fog S 6

9 New Figure 3 for the ASHRAE Handbook of Fundamentals, Psychrometrics Chapter, showing thermal conductivity values for moist air S Deliverable 3: Comparison of new algorithms Comparison of new algorithms for viscosity of moist air to the former equations by Mason and Monchick (965) S 8

10 Comparison of new algorithms for thermal conductivity of moist air to the former equations by Mason and Monchick (965) S Deliverable 4: Tables of Transport Properties of Water at Saturation ASHRAE Handbook Fundamentals, Ch. : Table Transport Properties of Water at Saturation (SI Edition) S

11 4.5 Deliverable 5: Update of Table for Refrigerant 78 (water/steam) ASHRAE Handbook Fundamentals, Ch. 3: Table Refrigerant 78 (Water/Steam) Properties of Saturated Liquid and Saturated Vapor (SI Edition) S 4.6 Timetable for Deliverables of ASHRAE RP-767 Deliverables. New SI and I-P moist air property tables for the ASHRAE Handbook of Fundamentals, Psychrometrics Chapter. New figures and 3 in the Psychrometrics Chapter of the ASHRAE Handbook of Fundamentals calculated from results of this research 3. Comparison of new algorithms for transport properties of moist air to former equations 4. SI and I-P transport properties of water at saturation for the liquid and the gas phase 5. Update of table for refrigerant 78 (water/steam) in the ASHRAE Handbook of Fundamentals, Chapter 3 6. Final report documenting all used equations and coefficients Schedule 6/3/7 /3/7 6/3/7 /3/7 6/3/7 /3/7 /3/6 /3/6 /3/7 6/3/8 (decision of TC. in Long Beach) S

12 5. Conclusions and Outlook Saturated water and steam properties done (finished by end of 6) Fortran code for calculating moist air transport properties prepared - using latest NIST equations for transport properties of dry air - incorporating current IAPWS formulations for water and steam - including an improvement of the current mixing model for transport properties of moist air New SI tables for the ASHRAE Handbook of Fundamentals, Psychrometrics Chapter were prepared, I-P tables in preparation New SI figures and 3 for the ASHRAE Handbook of Fundamentals, Psychrometrics Chapter, I-P figures in preparation Preparing the Final Report including all equations and coefficients by the end of June 8 Reporting the results of RP-767 in a track (seminar, ) as an oral presentation at the 8 ASHRAE Annual Conference in Houston, TX Preparing of a research paper for the Journal Science and Technology for the Built Environment (former HVAC&R Research) by end of September 8 S 3 References Herrmann, S.; Kretzschmar, H.-J.; Gatley, D.P.: Thermodynamic Properties of Real Moist Air, Dry Air, Steam, Water, and Ice. Report ASHRAE RP-485, American Society of Heating, Refrigeration, and Air-Conditioning Engineers, Inc., Atlanta, GA (9). Hochrainer, D.; Munczak, F.: Viscosity Measurements on Air of Different Humidity and Temperature. Sitzungsber., Österr. Akad. Wiss., Abt. II 75, (966) (in German). Huber, M.L.; Perkins, R.A.; Laesecke, A.; Friend, D.G.; Sengers, J.V.; Assael, M.J.; Metaxa, I.N.; Vogel, E.; Mareš, R.; Miyagawa, K.: New International Formulation for the Viscosity of HO. J. Phys. Chem. Ref. Data 38, -5 (9). Huber, M.L.; Perkins, R.A.; Friend, D.G.; Sengers, J.V.; Assael, M.J.; Metaxa, I.N.; Miyagawa, K.; Hellmann, R.; Vogel, E.: J. Phys. Chem. Ref. Data 4, 33 (). IAPWS. Revised Release on the IAPWS Industrial Formulation 997 for the Thermodynamic Properties of Water and Steam IAPWS-IF97. 7; available at IAPWS. Release on the IAPWS Formulation 8 for the Viscosity of Ordinary Water Substance. 8; available at IAPWS. Release on the IAPWS Formulation for the Thermal Conductivity of Ordinary Water Substance. ; available at IAPWS. Revised Release on the IAPWS Formulation 995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use. 4; available at IAPWS. Revised Release on Surface Tension of Ordinary Water Substance. 4; available at Kestin, J.; Whitelaw, J.H.: The Viscosity of Dry and Humid Air. Int. J. Heat Mass Transfer 7, (964). Kretzschmar, H.-J.; Wagner, W.: International Steam Tables. Springer, Berlin (7). Parry, W.T.; Bellows, J.C.; Gallagher, J.S.; Harvey, A.H.; Harwood, R.D.: ASME International Steam Tables for Industrial Use. ASME Press, New York (4). Vesovic, V.; Wakeham, W.A.: Prediction of the Viscosity of Fluid Mixtures Over Wide Ranges of Temperature and Pressure. Chem. Eng. Sci. 44, 8-89 (989). Vesovic, V.: Wakeham, W.A.: Prediction of the Thermal Conductivity of Fluid Mixtures Over Wide Ranges of Temperature and Pressure. High Temp.-High Press. 3, 79-9 (99). Wagner, W.; Pruß, A.: The IAPWS Formulation 995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use. J. Phys. Chem. Ref. Data 3, (). S 4