1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
BARSIC [14]
3 years ago
8

A steam Rankine cycle operates between the pressure limits of 1500 psia in the boiler and 2 psia in the condenser. The turbine i

nlet temperature is 800°F. The turbine isentropic efficiency is 90 percent, the pump losses are negligible, and the cycle is sized to produce 2500 kW of power. Calculate the mass flow rate through the boiler, the power produced by the turbine, the rate of heat supply in the boiler, and the thermal efficiency.
Physics
1 answer:
AlladinOne [14]3 years ago
5 0

Answer:

a. Mass flow rate through the boiler = 5.462lbm/s

b. Power produced by the turbine = 2525.8kW

c. The rate of heat supply in the boiler = 6901.42Btu/s

d. Thermal efficiency of the cycle = 34.3%

Explanation:

In order to provide a solution, we must assume that ;

- The system is operating at a steady condition

- Kinetic and potential energy changes are negligible

Now from steam tables, we calculate specific volume v and enthalpy h as,

h_1 = 95.96Btu/lb (  h_1 = h_f at 2psia )

v_1 = 0.016238ft^3/lb ( v_1 = v_f at 2psia )

w_{p,in} = v_1(P_2-P_1) = 0.016238(1500-2) * \frac{1}{5.404} = 4.501 Btu/lb

w_p = h_2 - h_1\\h_2 = w_p+h_1=4.501+95.96=100.461Btu/lb

h_3 = 1364.0Btu/lb

s_3 = 1.5073Btu/lb.R

( at P_3 = 1500psia & T_3 = 800^0F )

P_4 = 2psia\\S_4 = S_3\\x_4S = \frac{S_4-S_f}{S_{fg}}=\frac{1.5073-0.1783}{1.7374}=0.765

( S_f & S_{fg} when pressure is 2psia)

h_4S = h_f+x_4S*h_{fg}=95.96+(0.765)(1021.0)=877.025Btu/lb

n_T= \frac{h_3-h_4}{h_3-h_4S}\\ h_4=h_3-n_T(h_3-h_4S)=1364.0-0.90(1364.0-877.025)=925.7Btu/lb

Therefore,

q_{in}=h_3-h_2=1364.0-100.461=1263.54Btu/lb\\q_{out}=h_4-h_1=925.7-95.96=829.74Btu/lb\\w_{net}=q_{in}-q_{out}=1263.54-829.74=433.8Btu/lb

To calculate the mass flow rate of steam in the cycle, we use the formula

W_{net}=mw_{net}\\m=\frac{W_{net}}{w_{net}} =\frac{2500}{433.8}=5.763*(\frac{0.94782Btu}{1Kj} )=5.462lb/s

where 1Kj = 0.947817 Btu

The power output and the rate of heat addition are calculated thus,

W_{T,out}=m(h_3-h_4)=(5.462lb/s)*(1364-925.7)Btu/lb*(\frac{1Kj}{0.94782Btu} )\\=5.462*438.3*1.055=2525.8KW

Q_{in}=mq_{in}=5.462(1263.54)=6901.46Btu/s

The thermal efficiency of the cycle can be found thus;

n_{th}=\frac{W_{net}}{Q_{in}} =\frac{2500}{6901.46}*(\frac{0.94782Btu}{1Kj} ) =0.343

= 34.3%

You might be interested in
A heating element has a resistance of 180 Ω and draws a current of 1.60 A. What is its power?
iragen [17]

its either 288Watts or 112.5 Watts

5 0
3 years ago
Read 2 more answers
arzan, who weighs 700 N, swings from a cliff at the end of a convenient vine thatis 20 m long. From the top of the cliff to the
vekshin1

Answer:

= 7.07 m

Explanation:

The Tarzan reaches bottom of swing after descending 2.5 m,

change in his potential energy equals his kinetic energy at bottom of swing

m g h = (1/2) m v²   ,  

hence speed v of Tarzan at bottom of swing is given as  

v = ( 2 g h )1/2

= ( 2 × 9.8 × 2.5 )1/2

= 7 m/s

At the bottom of swing, if the vine breaks, then he is moving with horizontal velocity 7 m/s in gravitational field.  

If vertical distance from ground to bottom of swing is 5 m, then time t for Tarzan to reach ground is given by

S = (1/2)g t2 or   t = (2S/g)1/2

= ( 2 × 5 / 9.8 )1/2

= 1.01 s

Horizontal distance traveled by Tarzan = 1.01 × 7

= 7.07 m

7 0
3 years ago
What is the meaning of the reference point in electric potential?.
mrs_skeptik [129]

Answer:

<h3><u>ELECTRIC POTENTIAL</u></h3>

• the amount of work needed to move a unit charge from a reference point to a specific point against an electric field.

4 0
2 years ago
Compare and contrast the function of the thymus and spleen<br> needed asap
Helga [31]

Answer:The thymus stores and produces T lymphocytes and also releases hormones which aid in the maturation of the T lymphocytes while the spleen stores and release lymphocytes as well as macrophages which eradicate foreign substances that may harm the body.

Explanation:

6 0
3 years ago
Paper towels attracts electrons. You rib a paper towel on a plastic rod. The paper towel becomes ____ and the plastic rod become
SOVA2 [1]
B. Negative / postive
5 0
3 years ago
Other questions:
  • Need help with exercises 3,4,5<br><br> Will give brainliest!!!
    8·1 answer
  • The speed at which a light aircraft can take off is 120 km/h. (A) What is the minimum constant acceleration required for the pla
    9·1 answer
  • A woman is standing at the rim of a nonuniform cylindrical horizontal platform initially at rest. The platform is free to rotate
    15·1 answer
  • Examples were friction is not useful
    11·1 answer
  • Moe is carrying and supporting a large crate by exerting 1000 N. He is walking at constant velocity across a level, horizontal f
    10·1 answer
  • a portable DVD player requires six 1.5-volt batteries to operate.if the resistance in the circuitis 7.2 ohms. what's the current
    14·1 answer
  • What is the kinetic energy of a hammer that starts from rest and decreases its potential energy by 10 kJ?
    8·1 answer
  • If the half-life of a decaying isotope is 10 years, which statement is true after<br> 10 years?
    13·1 answer
  • A falcon can descend with a speed 250 km/h. If a falcon flies at this speed for 2.0 s and then flies a 100 m in 2.5 s, what is t
    14·1 answer
  • Which equation can be used to calculate the normal force on an object if you know the speed of the object, the coefficient of ki
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!