Dryness fraction

Constant dryness or constant quality lines Lines on a steam, gas, or psychro-metric chart passing through all the state points of equal dryness fraction. 

Dryness fraction of wet steam The mass of pure saturated steam contained in unit mass of wet steam. 

F = temperature, "Fahrenheit f = specific relief area, sq meter/cubic meter, or area/unit volume fq = steam quality, dryness fraction G = specific gravity of gas (air = 1), or specific gravity of liquid (water = 1) at actual discharge temperature... 

Gx mass flow of extra steam dryness fraction kg/s MT 1... 

However, the steam must entrain the smallest possible amount of condensate. The term steam dryness fraction defines the amount of condensate entrained by the moist steam. A dryness fraction of 0.95 means that lOOg of moist steam consist of 95 g of dry saturated steam plus 5 g of condensate, which is (or should be) at the same temperature the steam. A dryness fraction of 0.95 is considered the lower limit of adequacy for moist-heat sterilization. 

An isentropic expansion for superheated steam is well characterized by taking the exponent as y = 1.3, but the exponent changes markedly when the steam becomes saturated. The value of y appropriate in the saturated region will depend on the dryness fraction, a o, at the start of the expansion, where xq will depend on the local thermodynamic properties at stage inlet, ho. So, Vo, etc. ... 

If the working fluid is steam, check whether it is superheated or saturated at the first stage by comparing the inlet specific enthalpy, with the specific enthalpy of saturated steam appropriate to the inlet pressure, hg(po. ). If Aq.i [Pg.188]

Here x is the dryness fraction, which may be evaluated from equation (16.74) when the other quantities are available, or from the similar equation for specific entropy ... 

Equation (16.85) possesses the advantage that it is independent of efficiency calculations. Hence p criii/PoT may now be computed off-line from the main simulation in all cases where y i constant. The only exception is the case of wet steam, where the effective value of y depends on the dryness fraction, x. 

DRYNESS FRACTION OR QUALITY - Weight fraction of the vapor in a vapor-liquid mixture. 

In this model the state-velocity vector a incorporates a composition parameter, in our case [3] the dryness fraction x, so that... 

Dryness fraction of the steam (after superheating this increases to 1.0)... 

A steam driven turbine is used to produce work. The steam available at 180 bar and 500°C is expanded at constant entropy until the dryness fraction is 0.88. Calculate (a) the energy produced per kg of steam and (b) the energy produced as a fraction of the energy available in the inlet steam. How much energy in the form of latent heat is left in the exit stream ... 

The dryness fraction of 0.88 indicates that the stream leaving the turbine is 88 per cent steam and 12 per cent water. A constant entropy expansion is the ideal expansion for the production of maximum work, and more advanced work would show that the exit conditions are 5 bar and 152°C. 

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