Properties of steam

Steam International Association for Properties of Steam National Institute of Standards and Technology Gaithersburg, Md. 20899 Textiles International Bureau for Standardization of Man-made Fibers Lautengartenstrasse 12 CH-4010 Basle Switzerland... 

Fig. 2. Properties of steam, where ST = saturation temperature and numbers are in °C. Point A corresponds to 22.1 MPa, and lines B, C, and D to 8.27,...

Properties of steam can be divided iato thermodynamic, transport, physical, and chemical properties. In addition, the molecular stmcture and chemical composition of steam are of iaterest. It was at the start of iadustrialization, ca 1763, that thermodynamic relationships were first measured by Watt. A century later, ia 1859, Rankiae pubUshed his Manual of the Steam Engine, which gave a practical thermodynamic basis for the design and performance of steam engines. 

The thermodynamic and physical properties of pure steam are well estabUshed over the range of pressures and temperatures used. The chemical properties of steam and of substances ia steam, their molecular stmctures, and iateractions with the soHd surfaces of containments need to be more fliUy explored. 

Va.por Pressure. Vapor pressure is one of the most fundamental properties of steam. Eigure 1 shows the vapor pressure as a function of temperature for temperatures between the melting point of water and the critical point. This line is called the saturation line. Liquid at the saturation line is called saturated Hquid Hquid below the saturation line is called subcooled. Similarly, steam at the saturation line is saturated steam steam at higher temperature is superheated. Properties of the Hquid and vapor converge at the critical point, such that at temperatures above the critical point, there is only one fluid. Along the saturation line, the fraction of the fluid that is vapor is defined by its quaHty, which ranges from 0 to 100% steam. 

Calculated hy P. E. Liley from various steam tables for the lower temperatures and from Paper B-11 hy P H. Kesselman and Yu. I. Blank, 7tli. Int. Conf. Properties of Steam, Tokyo, 1968, for the higher temperatures. 

Steam tables Tables containing the ther modynamic properties of steam over a range of pressures and superheat. 

Values obtained from Keenan Keyes— Thermodynamic Properties of Steam". John Wiley Sons, 1936, by permission. 

Energy is not destructible. It can always be accounted for, and if it disappears at point A then it reappears in equal amount at point B. This ensures that the world is a consistent place and that energy does not mysteriously appear from or disappear to nowhere. In addition it ensures that the steam tables can be relied on always to provide information on the properties of steam. 

Values obtained directly or by interpolation from Keenan Keyes—"Thermodynamic Properties of Steam, John Wiley Sons, 1930 by permission and Courtesy C. H. Wheeler Co., Philadelphia, Pa. 

Internal development, 15 639 Internal diffusion, 9 97 Internal energy, as a property of steam, 23 204... 

Marshall, W.L. and Franck, E.U., Paper presented at International Association for the Properties of Steam, Sept. 1979, Munich, West Germany... 

Haar L., Gallager J. G., and Kell G. S. (1979). Thermodynamic properties of fluid water. In Contributions to the 9th Int. Conf. on Properties of Steam, Munich, Western Germany. 

Level Sengers J. M. H., Kamgar-Parsi B., Balfour E W., and Sengers J. V. (1983). Thermodynamic properties of steam in the critical region. J. Phys. Chem. Ref. Data, 12 1-28. 

Source Condensed from Keenan and Keyes, Thermodynamic Properties of Steam, Wiley, New York, 1936). 

Official Properties. The International Association for Properties of Water and Steam (IAPWS), an association of national committees that maintains the official standard properties of steam and water for power cycle use, maintains two formulations of the properties of water and steam. The first is an industrial formulation, the official properties for the calculation of steam power plant cycles. This formulation is appropriate from 0.001 to 100 MPa (0.12-1450 psia) and from 0 to 800 C (32-1472 F) and also from 0.001 to 10 MPa (0.12-145 psia) between 800 and 2000°C (1472 3632 F). This formulation is used in the design of steam turbines and power cycles. IAPWS maintains a second formulation of the properties of water and steam for scientific and general use from 0.01 MPa (extrapolating to ideal gas) at O C (1.45 psia at 32 F) to the highest temperatures and pressures for which reliable information is available. 

Refs l)L.A.Harding, Steam Power Plant Engineering , Wiley,NY(1932) 2)J.H.Keenar. F.G. Keyes,"Thermodynamic Properties of Steam , Wiley,NY(1936) 3)T.E.Butterfield et al, Steam and Gas Engineering ,Van Nostrand,NY(1947)... 

Keenan, J. H. Keyes, F. G. "Thermodynamic Properties of Steam" John Wiley Sons New York, 1986. 

Keenan JFI, Keys FG. Thermodynamic properties of steam. 1st ed. New York John Wiley Sons, Inc, 1936 28-73. 

We gratefully acknowledge the contributions of Professor Charles Mucken-fuss, of Debra L. Saucke, and of Eugene N. Dorsi, whose efforts produced computer programs for calculation of the thermodynamic properties of steam and ultimately the Steam Tables of App. C. We would also like to thank the reviewers of this edition Stanley M. Walas, University of Kansas Robert G. Squires, Purdue University Professor Donald Sundstrom, University of Connecticut and Professor Michael Mohr, Massachusetts Institute of Technology. Most especially, we acknowledge the contributions of Professor M. M. Abbott, whose creative ideas are reflected in the structure and character of this fourth edition, and who reviewed the entire manuscript. 

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