A vertical piston cylinder assembly contains 10.0kg of a saturated liquid-vapor water mixture with initial quality of 0.85 The water receives energy by heat transfer until the temperature reaches 320*C. The piston has a mass of 204kg and area of 0.005m2. Atmospheric pressure of 100kPa acts on the top side of the piston. Local gravitational acceleration is 9.81m/s2 Calculate the amount of heat transfer between the water and the surroundings in kJ. Enter a numeric value only. 6735.66

Explanation:

From the given information:

At state 1:

Initial Quality

mass = 10.0 kg

At state 2:

Temperature

mass of the piston

area of the piston

Atmospheric pressure

Gravitational acceleration = 9.81 m/s²

, This is because there exists no restriction to the movement of the piston and provided the process is frictionless. So, the process 1-2 is regarded as constant.

To calculate the applying force balance over the piston by using force balance in the vertical direction:

∴

(100 × 10³)×0.005 + 204 × 9.31 = P × 0.05

P = 500248 Pa

P = 500.25 kPa

At state 1:

Hence, this is a saturated mixture of liquid and vapor

Using the steam tables at 500.25 kPa

∴

Specific volume at state 1 is given as:

volume at state 1 is given by:

Similarly, the specific internal energy is:

At state 2:

Using steam tables at P = 500.25 kPa and T = 320° C

∴

a and b sometimes have a positive value