Question

8. A closed feedwater heater may be used for deaeration. a. True b. False
9. In a reciprocating power system,   i. Material flows at a constant rate through the device and passes through a turbine to produce shaft power output, ii. Material does not flow at a constant rate through every section of the device.   iii. Power is produced at all times. iv. Power is produced only during part of the cycle in each section of the device and is not produced uniformly at every instant.   v. The power unit consists of one or more piston and cylinder sections with intake and exhaust valves and where fresh fuel and air are taken in during one part of the process, exhaust gases are ejected during another part of the process, and at other times the cylinder is closed off from the intake and exhaust sections (manifolds).   vi. The power unit consists of a compressor, a burner section, and a turbine.   a. Items i), iii), and vi) are correct. b. Items ii) and iii) are correct. c. Items ii), iv) and v) are correct. d. Items ii), iv), and vi) are correct. e. None of these combinations are correct.

10. The Otto cycle model is used with … a. Reciprocating internal combustion engines where the fuel-air mixture is ignited by a spark. b. Reciprocating internal combustion engines where the fuel-air mixture is ignited by high pressures in the cylinders. c. Internal combustion engines with continuous flow of fuel and air (i.e., gas turbine engines). d. External combustion “hot air” engines. e. Vapor compression refrigeration.

11. In an air standard analysis, we pretend that the substance in an engine is pure air, and we analyze this as if energy is put into the air from the outside and, later, waste heat is removed from the air. a. True b. False




12. The Brayton cycle is used to model the operation of … a. Steam Power Plants b. Spark Ignition Internal Combustion Engines c. Compression Ignition Internal Combustion Engines d. Gas Turbine Engines e. Vapor Compression Refrigeration Machines f. None of these

13. For high thermal efficiency, the compression ratio in a spark ignition reciprocating engine is likely to be in the range of … a. 8:1 to 10:1. b. 15:1 to 20:1. c. 20:1 to 40:1. d. None of these are reasonable.

14. For high thermal efficiency, the compression ratio in a compression ignition reciprocating engine is likely to be in the range of … a. 8:1 to 10:1. b. 15:1 to 20:1. c. 20:1 to 40:1. d. None of these are reasonable.

15. The environmental aspects of refrigerants are important considerations in selection. a. True b. False

16. Ammonia may be used as a refrigerant. a. True b. False

17. Carbon Dioxide may be used as a refrigerant. a. True b. False  

Answer 1

8: True

9: e. None of these combinations are correct.

Correct answer is only iv &v

(iv. Power is produced only during part of the cycle in each section of the device and is not produced uniformly at every instant.   v. The power unit consists of one or more piston and cylinder sections with intake and exhaust valves and where fresh fuel and air are taken in during one part of the process, exhaust gases are ejected during another part of the process, and at other times the cylinder is closed off from the intake and exhaust sections (manifolds). )

10: a. Reciprocating internal combustion engines where the fuel-air mixture is ignited by a spark.

11. False ( In air standard analysis we pretend the air as ideal gas, it is calculated by the ratio of Net work done to the Net heat supplied)

12:  d. Gas Turbine Engines

13:d None of these are reasonable (The compression ratio for SI engine varies between 4:1 to 8:1)

14: d None of these are reasonable (The compression ratio for CI engine varies between 14:1 to 23:1)

15: True (Some refrigerantcan cause ozone depletion)

16: True

17:True