Using Charts and Tables

Question 1

How do you determine superheated steam properties using tables?

Answer 1

1. Identify pressure and temperature
2. Interpolate if necessary to find h, u or s

Question 2

How do you use a Mollier chart for enthalpy changes?

Answer 2

1. Locate the initial stage using pressure and enthalpy
2. Track process paths (e.g. isentropic, constant pressure)

Question 3

How do you calculate dryness fraction using a steam table?

Answer 3

x = (h - h_f) / h_fg

Where
h_f : Saturated liquid enthalpy

h_fg : Latent heat of vaporisation

Question 4

How do you calculate relative humidity from the psychrometric chart?

Answer 4

Find the intersection of the dry-bulb and wet-bulb temperatures and read ϕ.

Question 5

What does the psychrometric chart represent?

Answer 5

It provides relationships between properties of humid air, such as specific humidity, enthalpy, and relative humidity.