Handouts
LINK: Diesel Electric Power Plant
Topics:
Indicated Power
Brake Power
Three Phase Electric System
Engines at High Elevation
Fuel Density
Machine Foundations
Exercises
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1. A diesel electric plant supplies energy for Meralco. During 24 hours period, the plant consumed 230 gallons of fuel at 30oC and produce 4200 kW-hr. Industrial fuel used is 28oAPI and was purchased at P16.20 per liter at 15.6oAPI. What should be the cost of fuel to be purchased per kW-hr? a. 2.32 b. 1.81 c. 4.32 d. 3.30 2. A 800 Bhp diesel engine uses fuel oil at 30oAPI gravity, fuel consumption is 0.82 lb/bhp-hr. Cost of fuel is P18.34 per liter. For continuous operation, calculate the minimum volume of cubical day tank, in m3, at ambient temperature of 38oC. a. 6.32 b. 9.78 c. 7.11 d. 8.30 3. A diesel power plant uses fuel that has a density of 895.32 kg/m3 at 15.6oC. Calculate the heating value, in Btu/lb. a. 16327.35 b. 44835.55 c. 54661.32 d. 19317.34 4. A diesel power plant uses fuel with heating value of 45,068.32 kJ/kg. Find the density, in kg/L of fuel at 32oC? a. 0.6611 b. 0.5387 c. 0.7681 5. A diesel engine consumed 950 liters of fuel per day at 28oC. If the fuel was purchased at 15.6oC and 32oAPI at P4.35 per L, determine the cost of fuel to operate the engine per day. a. 3284.21 b. 5037.31 c. 4096.83 d. 6678.21 6. A cylindrical tank 2.8 m long and 2.5 m diameter is used for oil storage. How many days can the tank supply the engine having 26oAPI with fuel consumption of 68 kg/hr? a. 6.3 b. 7.6 c. 8.1 d. 5.4 7. The specific gravity of fuel oil having a heating value of 44,900.3 kJ/kg is: a. 0.6873 b. 0.7731 c. 0.8927 d. 0.9161 8. During the dynamometer test of an engine for 1 hour steady load, the engine consumes 45 kg fuel having 43,500 kJ/kg heating value. If the torque developed is 3.2 kN-m during the test of 580 rpm, what is the efficiency of the engine? a. 35.74% b. 38.22% c. 42.01% d. 32.65% 9. A 4-stroke Gasoline engine has a bore and stroke of 410 mm x 460 mm running at 810 rpm. If the clearance volume is 0.06632 m3/s, calculate the engine efficiency. b. 48.21% c. 38.25% d. 44.21% 10. A 3.2 MW diesel engine consumes 250 L of 26oAPI fuel and generates 950 kW-hr. Determine the rate of fuel consumed by the engine. a. 0.1109 kg/s b. 0.2102 kg/s c. 0.3233 kg/s d. 0.4121 kg/s 11. A 22 cm x 38 cm engine, with 4 cylinders and operating on a four stroke, has a rated power of 180 kW and is running at 280 rpm. Determine the volume displacement per brake power developed. a. 0.05512 m3/kW-min b. 0.03122 m3/kW-min c. 0.04494 m3/kW-min d. 0.02199 m3/kW-min 12. A 2600 kW diesel engine unit uses 1 bbl oil per 560 kWh produced. Oil is 30oAPI. Efficiency of generator is 85%, mechanical efficiency of engine is 80%. What is the thermal efficiency of engine based on indicated power, in percent? a. 32.3% b. 47.0% c. 52.1% d. 48.9% 13. A single-acting, four-cylinder, 4 stroke cycle diesel engine with a bore and stroke of 23 cm x 30 cm, operating at 385 rpm, consumes 8.9 kg/hr of fuel with a heating value of 45,300 kJ/kg. The indicated mean effective pressure is 550 kPa, the load on the brake arm, which is 110 cm is 120 kg. What is the brake mean effective pressure, in kPa? a. 326.38 b. 401.22 c. 300.21 d. 359.77 14. In a double acting, 2-stroke compression ignition engine, 12 cylinder, the diameter of the cylinder is 760 mm, stroke is 1500 mm and the piston rod diameter is 250 mm. When running at 130 rpm, the indicated mean effective pressure above and below the pistons are 7 bar and 6 bar, respectively. Determine the brake power of the engine with a mechanical efficiency of 85%, in kW? a. 16873.52 b. 19441.35 c. 20179.22 d. 18573.21 15. Determine the output power (kW) of a diesel power plant if the engine and generator efficiency is 85% and 90%, respectively. The engine uses 26oAPI fuel and has a fuel consumption of 0.09 kg/s. a. 2831.69 b. 3511.28 c. 2566.11 d. 3081.70 16. Determine the brake power of an engine having a brake thermal efficiency of 40% and uses 26oAPI fuel with fuel consumption of 45 kg/hr. a. 200.12 b. 312.33 c. 223.80 d. 367.77 17. A diesel engine develops a torque of 6 kN-m at 1900 rpm. If the brake thermal efficiency is 35%, determine the heat generated by fuel. a. 2400.1 kW b. 3410.87 c. 1193.81 d. 1897.66 18. A 600 kW diesel engine operates at 100 kPa and 28oC in Manila. If the engine operates in Baguio having 93 kPa and 20oC, what new brake power developed if the mechanical efficiency is 80%? a. 665.50 kW b. 750.00 kW c. 566.50 kW d. 716.50 kW 19. A 55 Bhp blast furnace engine uses fuel with 12 ft3/Bhp-hr. The heating value of gas is 35,800 kJ/m3. Determine the brake thermal efficiency. a. 22.06% b. 25.11% c. 28.32% d. 30.00% 20. During the dynamometer test of an engine for 1 hr steady load, the engine consumes 45 kg fuel having 45,000 kJ/kg heating value. If the torque developed is 2.8 kN-m during the test at 610 rpm, what is the brake thermal efficiency? a. 31.79% b. 28.26% c. 38.28% d. 25.31% 21. Find the power which a 3.0 MW natural gas engine can develop at an altitude of 1900.3 m taking into consideration the pressure change alone. a. 1.37 MW b. 3.68 MW c. 4.87 MW 22. What is the required base area in square feet of a foundation supporting an engine with specific speed of 1300 rpm, and weight of 12000 kg. Assume a bearing capacity of soil as 50 kPa. Use e=0.12 a. 124.9 c. 234.8 d. 101.9 |
Diesel Engine
A single cylinder, single acting, 305 mm x 460 mm, four cycle diesel engine was tested for one hour and the following data were obtained: Total revolutions = 12120 rpm; Area of the indicator card = 5.5 sq. cm; Length of the indicator card = 7 cm; Scale of the indicator spring = 80 MPa; Torque due to brake load = 120 kg-m. Find the (a) Indicator power (b) Brake power (c) Mechanical efficiency.
SOLUTION:
CLICK: Engine Construction
CLICK: Engine Types
Fuel Properties
A diesel electric power plant in one of the remote provinces in the South utilized diesel fuel with an API of 28 degrees at 15.6 deg C. The plant consumes 680 Liters of diesel fuel at 26.6 deg C in 24 hours, while the power generated for the same period amounts to 1980 kW-hrs. Determine the following (a) Density of fuel at 26.6 deg C, in kg/L (b) Fuel rate, in kg/kW-hrs (c) The higher heating value, in J/g.
SOLUTION:
