THERMODYNAMICS

ASSIGNMENT

EC41FA2

Submitted to:

Engr. Joel Gatchalian

Date Submitted:

July 28, 2011

NAMES:

Almarez, Melvin

Balisi, Baby Liezel

Claravall, Justine

Jarabe, Crystel Ann

Jose, Michell Anne

Mercene, Ma. Laeka Ann

Sarmiento, Czarina Jean

Talavera, Jayson D.

1. Assuming that there are no heat effects and no

frictional effects, find the kinetic energy and speed of

a 3220-lb body after it falls 778 ft from rest. Start with

the steady flow equation,

deleting energy terms

which are irrelevant.

Solution:

2. A reciprocating compressor draws in 500 cubic feet per minute of air whose density is 0.079 lb/cu.ft and discharges it

with a density of 0.304 lb/cu.ft. At the suction, p1=15 psia; at discharge, p2= 80 psia. The increase in the specific

internal energy is 33.8 Btu/lb and the heat transferred from the air by cooling is 13 Btu/lb. Determine the work on the

air in Btu/min and in hp. Neglect change in kinetic energy.

Solution:

3. Steam enters a turbine with an enthalpy of 1292

Btu/lb and leaves with an enthalpy of 1098 Btu/lb. The

transferred heat is 13 Btu/lb. What is the work in Btu/min

and in hp for a flow of 2

lb/sec?

Solution:

4. A thermodynamic steady flow

system receives 4.56 kg per min of

a fluid where p1=137.90 kPa,

v1=0.0388 m3/kg, Ѵ1=122 m/s, and

u1=17.16 kJ/kg. The fluid leaves the

system at a boundary where

p2=551.6 kPa, v2=0.193 m3/kg,

Ѵ2=183 m/s and u2=52.80 kJ/kg.

During the passage through the

system the fluid receives 3000 J/s

of heat. Determine the work.

Solution:

5. Air flows steadily at the rate of 0.5 kg/s through an air compressor, entering at 7 m/s speed, 100 kPa pressure and

0.95 m3/kg specific volume, and leaving at 5 m/s, 700 kPa, and 0.19 m3/kg. The internal energy of the air leaving is 90

kJ/kg greater than that of the air entering. Cooling water in the compressor jackets absorbs heat from

the air at the rate of 58 kW. Compute the work in kW.

Solution:

6. In a steady flow apparatus, 135 kJ of

work is done by each kg of fluid. The

specific volume of the fluid, pressure, and

speed at the inlet are 0.37 m3/kg, 600 kPa,

and 16 m/s. The inlet is 32 m above the

floor, and the discharge pipe is at the floor

level. The discharge conditions are 0.62

m3/kg, 100 kPa, and 270 m/s. The total

heat loss between the inlet and discharge

is 9 kJ/kg of fluid. In flowing through this

apparatus, does the specific internal

energy increase or decrease, and by how

much?

Solution:

7. Steam enters a turbine

stage with an enthalpy of

3628 kJ/kg at 70 m/s and leaves the same stage with

an enthalpy of 2846 kJ/kg and a velocity of 124 m/s.

Calculate the work done by the steam.

Solution:

Group Pictures:

THE END……