Chapter 2, Problem 2.40P

A hygrometer, which measures the amount of moisture in a gas stream, is to 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:

Mass Fraction of Water, y	Hygrometer Reading, R
0.011	5
0.044	20
0.083	40
0.126	60
0.170	80

1. Draw a calibration curse and determine an equation for y(R).
2. 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 the gas?