local exhaust ventilation 3
2.Cyclone can be used as an air cleaning device in LEV system. Use your own words to discuss how cyclone can work to clean contaminated air.
3.
Use your own word to explain what the vena contracta is, and where it is located in the LEV system.
4.
Review ABIH 9-e table, and use your own words to describe how changes in curvature (R/D) and the transition (pieces) of round elbow can affect the loss factor K.
5.What are two major functions of static pressure? Please explain where static pressure losses occurs in the LEV system?
6.Use you own words to discuss why and how energy losses occur in local exhaust ventilation system. At least 4 factors need to be discussed.
8.
What is the friction loss when air flows through a round galvanized duct with duct diameter of 5 inches and the length of 10 ft, and at an average velocity V = 4,000 fpm? Assume STP and df=1. The result should be rounded to 2 decimal places, and appropriate unit should be included for full credits. Hint: use equation 25 and 26 in textbook.
10.
We have discussed several different losses including duct friction loss, elbow loss and branch entry loss. Why these losses are the square function of velocity (V^2)?
11. What is the 90-degree elbow loss factor (K elbow) where the elbow radius of curvature is R/D = 1.0 in a smooth transition elbow?
12. How changes in velocity, velocity pressure and duct diameter can affect duct friction loss?
