A hygrometer, which measures the amount of moisture in a gas stream, is be calibrated using the apparatus shown here. Steam and dry air are fed at known flow rates and mixed to form a gas stream with a known water content, and the hygrometer reading is recorded; the flow rate of either the water or the air is changed to produce a stream with a different water content and the new reading is recorded, and so on. The following data are taken:

(a) Draw a calibration curve and determine and equation for y(R).

(b) Suppose a sample of a stack gas is inserted in the sample chamber of the hygrometer and a reading of R = 43 is obtained. If the mass flow rate of the stack gas is 1200 kg/h, what is the mass flow rate of water vapor in thegas?

Air Water Dryer 1101112 Rotameters 0.011 0.044 0.083 0.126 0.170 mich Mass Fraction of Water, y Evaporator Hygrometer Reading, R 5 20 40 60 80 Hygrometer Steam