Dhaka Electric Supply Company Limited (DESCO)

Dhaka Electric Supply Company Limited (DESCO)

Post: Sub-Assistant Engineer (Mechanical)

Time-10.00Am to 11.30 Am

Exam Buet

Full Marks-( ME-35, Non- Departmental= 60*.05=30)

1. A refrigerator can introduce 1000kg of ice 0 degree C in 6 hours. Determine the tonnage capacity of the refrigeration in TOR and KW.

2. Draw the block diagram of a vapor compression refrigeration system and shown the cycle in P-h and T-S plane with sub-cooling.

3. A pressure gauge attached to a rigid tank reads a vacuum of 60 Kpa . If the atmospheric pressure is 12m of water column, find the absolute pressure of air inside the tank in Kpa.

4. Draw the P-V and T-S diagram and the name of the different processes involved in a four stroke petrol engine.

5. A diesel engine has a compression ratio of 20 and cut-off takes place at 5% of the stroke. Find the air standard efficiency, Assume y= 1.4

6.  Heat is transferred from 2m*3, m steel plate due to the flowing of air with heat transfer co-efficient of 5.5 w/m2 degree C. The temperature of the path is 80 degree C and that of the flowing air is 25 degree C. Calculate the amount of heat transfer.