Rework Example 11.1 using the HDI method and tables for the properties of air, and compare the results with the example. Which answer do you think is the best, and why? (You should have access to a computer database file for the thermodynamic properties of various gases and vapors.)

Example 11.1 A relief valve must be selected to discharge a vessel at a rate of 75 lb/s when fully open from a vessel for which the maximum allowed pressure is 150 psia. The fluid is a vapor with a molecular weight of 45, which can be considered an ideal gas, with a specific heat ratio of 1.3, a tempera- ture of 70F, and it is discharged into the atmosphere. Determine the diameter of the nozzle in the valve that should be selected (Note: if the calculated nozzle area does not match any of the standard sizes available, the next larger size is selected. An additional 10% is also usually added to the calculated nozzle area as a "safety factor.")