Heat engineering; a text book of applied thermodynamics for engineers and students in technical schools . madeby keeping the pressure constant, heating the water from 32° the boiling point, boiling to dry vapor and then superheating atconstant pressure. If superheating takes place the temperaturewill rise by the degrees of superheat and the entropy will increase by J Cpdt the line will therefore take the shape cd. The broken line abedis a line of constant pressure. The area beneath cd is /? cvdt If the steam is wet the change of entropy from the liquid XT condition is ^-, and hence if poi
Heat engineering; a text book of applied thermodynamics for engineers and students in technical schools . madeby keeping the pressure constant, heating the water from 32° the boiling point, boiling to dry vapor and then superheating atconstant pressure. If superheating takes place the temperaturewill rise by the degrees of superheat and the entropy will increase by J Cpdt the line will therefore take the shape cd. The broken line abedis a line of constant pressure. The area beneath cd is /? cvdt If the steam is wet the change of entropy from the liquid XT condition is ^-, and hence if point e is so selected that bebe = x the point e represents the condition of quality x since be = ^. If now for various temperatures (and consequently saturation pressures) various points befound, having the samevalue of x, a line of constantquality or constant steamweight may be obtained asshown in Fig. 14. In the superheated regionthis is replaced by lines of<* constant amount of super-heat. In this case pointson various pressure lines atthe same number of de-grees above saturation Lines on TS plane. If the value of i be computed for point e and this is made equalto the i at some other temperature the quality at this point maybe found and from it the position of e on that line. q + xr = q\ + xiTi q + xt - q\ri Xi = FUNDAMENTAL THERMODYNAMICS 51 If a number of points are found, a line of constant heat contentis obtained. In the superheated region q + r + I Cpdt = q\ + ri + j Cpdt and the values of the degrees of superheat at the second pres-sures are found to give the same heat content as at the first points form the line of constant heat is known that u = q + xp or u = i — Apv Hence if the value of u at point e is equated to the expression atanother pressure or temperature, the quality x or the degrees ofsuperheat may be found for the second pressure or temperatureand this fixes the position of the point. Connecting a seriesof these the
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1915
