Power Plant Engineering
BRAKE HORSE POWER (B.H.P.)
Download 3.45 Mb. Pdf ko'rish
|
Power-Plant-Engineering
- Bu sahifa navigatsiya:
- 8.8.4 FRICTIONAL HORSE POWER (F.H.P.)
- 8.8.6 BRAKE THERMAL EFFICIENCY (OVERALL EFFICIENCY)
- 8.9 FUEL SYSTEM OF DIESEL POWER PLANT
8.8.3 BRAKE HORSE POWER (B.H.P.)
Brake horse power is defined as the net power available at the crankshaft. It is found by measur- ing the output torque with a dynamometer. B.H.P. = 2 NT 4500 Π where T = Torque in kg.m. N = Speed in R.P.NT. 8.8.4 FRICTIONAL HORSE POWER (F.H.P.) The difference of I.H.P. and B.H.P. is called F.H.P. It is utilized in overcoming frictional resist- ance of rotating and sliding parts of the engine. F.H.P. = I.H.P. – B.H.P. 8.8.5 INDICATED THERMAL EFFICIENCY ( ηηηηη i ) It is defined as the ratio of indicated work to thermal input. η i = (I.H.P. 4500) (W C J) v × × × where W = Weight of fuel supplied in kg per minute. C V = Calorific value of fuel oil in kcal/kg. J = Joules equivalent = 427. 8.8.6 BRAKE THERMAL EFFICIENCY (OVERALL EFFICIENCY) It is defined as the ratio of brake output to thermal input. η b = (B.H.P. 4500) (W C J) × × × v 8.8.7 MECHANICAL EFFICIENCY ( ηηηηη m ) It is defined as the ratio of B.H.P. to L.H.P. Therefore, η m = B.H.P. L.H.P. DIESEL POWER PLANT 241 8.9 FUEL SYSTEM OF DIESEL POWER PLANT The fuel is delivered to the plant by railroad tank car, by truck or by barge and tanker and stored in the bulk storage situated outdoors for the sake of safety. From this main fuel tank, the fuel oil is transferred to the daily consumption tank by a transfer pump through a filter. The capacity of the daily consumption should be atleast the 8-hour requirement of the plant. This tank is located either above the engine level so that the fuel flows by gravity to the injection pump or below the engine level and the fuel oil is delivered to the injection pump by a transfer pump driven from the engine shaft, Fig. 8.3. Fuel connection is normally used when tank-car siding or truck roadway is above tank level. If it is below tank level, then, an unloading pump is used to transfer fuel form tank car to the storage tank (dotted line). Foot Valve and Strainer Unloading Pump Sounding Well Fill Connection Manhole Vent Day Tank To Engine Transfer Pump Strainer Suction Line Crain Tank car Fig. 8.3. Fuel System. The five essential functions of a fuel injection system are: 1. To deliver oil from the storage to the fuel injector. 2. To raise the fuel pressure to the level required for atomization. 3. To measure and control the amount of fuel admitted in each cycle. 4. To control time of injection. 5.To spray fuel into the cylinder in atomized form for thorough mixing and burning. The above functions can be achieved in a variety of ways. The following are the systems, which are usual on power station diesels: 1.Common Rail. 2.Individual Pump Injection. 3. Distributor. Download 3.45 Mb. Do'stlaringiz bilan baham: |
Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan ©fayllar.org 2024
ma'muriyatiga murojaat qiling
ma'muriyatiga murojaat qiling