A spherical hot air balloon is initially filled with air having 120 kPa pressure and 24 °C temperature. Initial diameter of the
1 answer:
Answer:
v = 1.076 m /s
Explanation:
Initial volume of balloon = 4/3 x 3.14 x (9.905/2)³
=508.56 m³
Final volume of balloon = 4/3 x 3.14 x (16.502/2)³
= 2351.73 m³
Increase in volume = 1843.17 m³
Cross sectional area of inlet A = 3.14 x( 1.458/2)²
A = 1.6687 m²
Volume rate of flow of air = cross sectional area x velocity of inflow
= 1 .6687 V [ V is velocity of inflow ]
Total time taken = Increase in volume / rate of flow of air
17.108 X 60 = 1843.17 / 1.6687 V
V =
v = 1.076 m /s
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Explanation:
R total = 4.25 ohm
I total = Vt/Rt
I total= 17/4.25= 4 A
Ix= 600 mA
Answer:
flow(m) = 54.45 kg/s
thermal efficiency u = 44.48%
Explanation:
Given:
- P_1 = P_8 = 10 KPa
- P_2 = P_3 = P_6 = P_7 = 800 KPa
- P_4 = P_5 = 10,000 KPa
- T_5 = 550 C
- T_7 = 500 C
- Power Output P = 80 MW
Find:
- The mass flow rate of steam through the boiler
- The thermal efficiency of the cycle.
Solution:
State 1:
P_1 = 10 KPa , saturated liquid
h_1 = 192 KJ/kg
v_1 = 0.00101 m^3 / kg
State 2:
P_2 = 800 KPa , constant volume process work done:
h_2 = h_1 + v_1 * ( P_2 - P_1)
h_2 = 192 + 0.00101*(790) = 192.80 KJ/kg
State 3:
P_3 = 800 KPa , saturated liquid
h_3 = 721 KJ/kg
v_3 = 0.00111 m^3 / kg
State 4:
P_4 = 10,000 KPa , constant volume process work done:
h_4 = h_3 + v_3 * ( P_4 - P_3)
h_4 = 721 + 0.00111*(9200) = 731.21 KJ/kg
State 5:
P_5 = 10,000 KPa , T_5 = 550 C
h_5 = 3500 KJ/kg
s_5 = 6.760 KJ/kgK
State 6:
P_6 = 800 KPa , s_5 = s_6 = 6.760 KJ/kgK
h_6 = 2810 KJ/kg
State 7:
P_7 = 800 KPa , T_7 = 500 C
h_7 = 3480 KJ/kg
s_7 = 7.870 KJ/kgK
State 8:
P_8 = 10 KPa , s_8 = s_7 = 7.870 KJ/kgK
h_8 = 2490 KJ/kg
- Fraction of steam y = flow(m_6 / m_3).
- Use energy balance of steam bleed and cold feed-water:
E_6 + E_2 = E_3
flow(m_6)*h_6 + flow(m_2)*h_3 = flow(m_3)*h_3
y*h_6 + (1-y)*h_3 = h_3
y*2810 + (1-y)*192.8 = 721
Compute y: y = 0.2018
- Heat produced by the boiler q_b:
q_b = h_5 - h_4 +(1-y)*(h_7 - h_8)
q_b = 3500 -731.21 + ( 1 - 0.2018)*(3480 - 2810)
Compute q_b: q_b = 3303.58 KJ/ kg
-Heat dissipated by the condenser q_c:
q_c = (1-y)*(h_8 - h_1)
q_c= ( 1 + 0.2018)*(2810 - 192)
Compute q_c: q_c = 1834.26 KJ/ kg
- Net power output w_net:
w_net = q_b - q_c
w_net = 3303.58 - 1834.26
w_net = 1469.32 KJ/kg
- Given out put P = 80,000 KW
flow(m) = P / w_net
compute flow(m) flow(m) = 80,000 /1469.32 = 54.45 kg/s
- Thermal efficiency u:
u = 1 - (q_c / q_b)
u = 1 - (1834.26/3303.58)
u = 44.48 %
Answer:
The initial temperature will be "385.1°K" as well as final will be "128.3°K".
Explanation:
The given values are:
Helium's initial volume, v₁ = 6 m³
Mass, m = 1.5 kg
Final volume, v₂ = 2 m³
Pressure, P = 200 kPa
As we know,
Work,
On putting the estimated values, we get
⇒
⇒
⇒
Now,
Gas ideal equation will be:
⇒
On putting the values. we get
⇒
⇒
⇒ (Initial temperature of helium)
and,
⇒
On putting the values, we get
⇒
⇒
⇒ (Final temperature of helium)