Please answer all the following questions Solve the following problems. Show all

Question

Please answer all the following questions

Solve the following problems. Show all work, and express your answers in appropriate units 1. (20 points) A rigid tank with a volume of1.3 m3 is initially filled with water at 150 kPa and 200°C. The water is then cooled to 75°C. Determine m V a) The initial specific 2no b) volume in m3/kg State 1 h a bles c) The mass of the water in kg. The initial internal energy in kJ. e) The phase or mixture). The final pressure of the water in VI :1, 3m3 The final internal energy in kl. ate 2 g) The heat transferred from the water in kl

Explanation / Answer

V = 1.3m^3

P = 150kPA

Ti = 573K

Tf = 348K

At, 150kPa , T_sat = 111.37 'C

T>T_sat , so water is in superheated state.

a) initial specific volume = 1.625 m^3/kg

b) Mass of water = Volume/ specific volume = 1.3/1.625 = 0.8 kg

c) Initial internal energy = mass* internal energy (kj/kg) = 2656.22*0.8 = 2124.976 kJ

d )Heat transfered = m*Cv*delta(T) = 0.8* 4.18*125 = 418kJ

Remaining energy = 2124.976 - 418 = 1706.97 kJ

At, temperature = 75'C,

internal energy_f = 0.8*313.87 =251.09 kJ

internal energy_g = 0.8*2475.91 = 1980.7 kJ

As internal energy_f < Remaining energy < internal energy_g

So, water is in satureted condition

let x be the quality of water

1706.97 = 313.87 + x*2162.03

x = 0.644

d) m_g = 0.644*0.8 = 0.515 kg

m_l = 0.8 - 0.538 = 0.284kg

Final phase is a mixture of gas and liquid with quality = 0.644

e) Final pressure =P_sat = 38.58kPa

f) Final internal energy = 1706.97 kJ

g) Heat transfered from water = 418kJ

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---