Mechanical Engineering Answers

If the coefficient of friction is 0.3 and Contact angle is 850, determine the transmitted

breaking torque for the following shoe brake.

Determine the specific volume, specific entropy and specific internal energy of steam at a pressure of 2MN/m² and with a temperature of 325°C

A quantity of a fluid with an initial pressure of 500KPa and an initial volume of 1m3 is made to undergo as process w/in a piston-cylinder system, Compute the work done by the fluid according to the condition that pressure is proportional to the square of volume. Express your answer in J.

Work is done by a substance in reversible nonflow manner during which 32 KJ are added, the pressure remains constant at 200KPa, the volume changes from .5m3 to.25m3. Compute the change in internal energy in KJ.

85) A 1-kg steam-water mixture at 1.0 MPa is contained in an inflexible tank. Heat is added until the pressure rises to 3.5 MPa and the temperature to 400: Determine the heat added

Unit mass of certain fluid is contained in a

cylinder at an initial pressure of 20 bar. The fluid

is allowed to expand reversibly behind a piston

according to a law Pv2=constant until the volume

is doubled. The fluid is then cooled reversibly at

constant pressure until the piston regains its

original position; heat is then supplied reversibly

with the piston firmly locked in position until the

pressure rises to the original value of 20 bar.

Calculate the net work done by the fluid, for an

initial volume of 0.05m

• A steam with a velocity of 600m/s enters an impulse turbine row of bladee at an angle of 25°C to the plane of rotation of the blades. The mean blade speed is 255m/s. The exit angle from the blades is 30°C. There is a 10% loss in-relative velocity due to friction in the blades. Determine:

(a) the entry angle of blades

(b) the work done /kg steam/s

(c) the diagram efficiency

(d) the end thrust/kg steam/ s

A long and rectangular metal blade is 4cm thick and has a surface temperature of 40°C. Both sides of the blade are in an environment of 20°C. the surface of the blade;

a) In case of vertical,

b) In case of inclination of 45°,

c) Find the temperature changes in case of horizontal.

2. Water enters a pipe at a temperature of 27°C and a flow rate of 450 kg/h. Heat flux is applied from outside the pipe, q'=ax (W/m). Here, a=20 W/m2 is a constant and x(m) is the length from the entrance.

a) Find the average temperature of the water flowing through the pipe as a function of the pipe length.

b) Find the outlet temperature of the water from a 30 m long pipe. (cp=4179 J/kgK)

1. A pipe with an inner diameter of 15 mm and a length of 2 m is heated with a constant heat flux. 8 kg of water flows through the pipe per hour and its temperature rises from 20 oC to 60 oC. According to this;

a. Find the pipe surface temperature and the average fluid temperature as a function of pipe length.

b. Find the constant heat flux.