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
taurus [48]
3 years ago
14

A steam power plant operates on an ideal Rankine cycle with two stages of reheat and has a net power output of 120 MW. Steam ent

ers all three stages of the turbine at 500°C. The maximum pressure in the cycle is 15 MPa, and the minimum pressure is 5 kPa. Steam is reheated at 5 MPa the first time and at 1 MPa the second time. Show the cycle on a T-s diagram with respect to saturation lines, and determine (a) the thermal efficiency of the cycle and (b) the mass flow rate of the steam.

Engineering
1 answer:
uysha [10]3 years ago
7 0

Answer:

a) 40.6%

b)72.19kg/s

Explanation:

The Rankine cycle with two reheat stages has 9 stages in total.

The maximum pressure will be at the first inlet stage of the HP turbine which is stage 3. The minimum pressure will be the exit stage of the condenser because the condenser operates under vacuum pressure which is stage 1.

The following assumptions can be made:

1 - Each component in the cycle is analyzed as an open system operating at steady-state.

  2 - All of the processes are internally reversible.

  3 - The turbine and pump operate adiabatically and are internally reversible, so they are also isentropic.

   4 - Condensate exits the condenser as saturated liquid.

  5 - The effluent from the HP turbine is a saturated vapor.

  6 - No shaft work crosses the system boundary of the boiler or condenser.

   7 - Changes in kinetic and potential energies are negligible

a) The thermal efficiency of the cycle is defined as the work of the cycle divided by the total heat input to the system. The stages that have heat input is stages 2-3, 4-5, 6-7.

For stage 2:

s₁=s₂ assuming isentropic

s_1=0.4762 @ P_1=15MPa

enthalpy will be a compressed liquid so after interpolation

h_2=97.93+(0.4762-0.2932)((180.77-97.93)/(0.5666-0.2932))=153.38kJ/kg

For stage 3:

Superheated steam @ T=500⁰C and P=15MPa

h_3=3310.8kJ/kg

Stage 4:

superheated vapor

P=5MPa

s₃=s₄=6.3480 kJ/kg, we must use interpolation to find h₄

h_4=2925.7-(6.348-6.2111)((3069.3-2925.7)/(6.4516-6.2111))=3007.44kJ/kg

Stage 5:

Superheated steam @ T=500⁰C and P₄=P₅=5 MPa

h_5=3434.7kJ/kg

Stage 6:

Superheated steam at P₆= 1MPa

s₅=s₆

s_6=6.9781

We find h₆ using interpolation from the steam tables:

h_6=2943.1-(6.9781-6.9265)((3051.6-2943.1)/(7.1246-6.9265))=2970.67kJ/kg

Stage 7:

P₇=P₆=1MPa

T=500⁰C superheated steam

h_7=3479.1kJ/kg

The heat into the cycle is:

=(h_3-h_2)+(h_5-h_4)+(h_7-h_6)

=(3310.8-153.38)+(3434.7-3007.44)+(3479.1-2970.67)=4108.74kJ/kg

We can determine the work out by the condenser from stage 9 to stage 1:

Stage 1:

saturated liquid P=5kPa

h_1=137.75kJ/kg

Stage 9:

We assume that its a saturated liquid with quality of 1 at 5kPa and

s₇=s₉ and after interpolation

h_9=2568.53kj/kgK

Qout = [/tex]2568.53-137.75=2430.79kJ/kg[/tex]

The thermal efficiency can be written in terms of qin and qout:

n=1-(q_o/q_i)=1-2430.79/4093.11=0.4061

Efficiency of 40.61%

b)

The mass flow rate can be calculated from the Wnet:

W_n=W_t-W_p

Work of the turbines minus the work of the pumps:

W_n=m((h_3-h_4)+(h_5-h_6)+(h_7-h_9)-(h_1-h_2)

120000=m(1662.33)

m=72.19

mass flow rate of steam is 72.19 kg/s

You might be interested in
Please help I need it by today!!!
AfilCa [17]

Answer:

if engineering disappeared for a day i would be at a loss. i wouldnt know what to do with myself considering engineering is my life. one way that engineers improve my life is they help me to understand enything end everything

Explanation:

7 0
2 years ago
The toggle (t) flip-flop has one input, clk, and one output, q. on each rising edge of clk, q toggles to the complement of its p
jeyben [28]

Answer:

  See attached

Explanation:

The next state of a toggle flip-flop is the inverse of the present state. This behavior can be produced using a D flip-flop that has its input connected to the inverse of its output.

__

A schematic is attached.

7 0
1 year ago
A gas mixture containing 3 moles CO2, 5 moles H2 and 1 mole water is undergoing the following reactions CO2+3H2 →cH3OH + H2O Dev
Ilya [14]
Aaaaaaaaaaaaaaaaaaaaaa
7 0
2 years ago
Discuss the applications of numerical weather forecasting​
olchik [2.2K]

Numerical weather prediction (NWP) uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. Though first attempted in the 1920s, it was not until the advent of computer simulation in the 1950s that numerical weather predictions produced realistic results. A number of global and regional forecast models are run in different countries worldwide, using current weather observations relayed from radiosondes, weather satellites and other observing systems as inputs.
3 0
2 years ago
List and describe three classifications of burns to the body.
DiKsa [7]

AnswerWhat Are the Classifications of Burns? Burns are classified as first-, second-, or third-degree, depending on how deep and severe they penetrate the skin's surface. First-degree burns affect only the epidermis, or outer layer of skin. The burn site is red, painful, dry, and with no blisters.

Explanation:

8 0
3 years ago
Read 2 more answers
Other questions:
  • Explicar el funcionamiento de un multímetro analógico.
    7·1 answer
  • Nitrogen gas flows through a long, constant-diameter adiabatic pipe. It enters at 100 psia and 120°F and leaves at 50 psia and 7
    14·2 answers
  • Define the Problem
    11·1 answer
  • What is the first step in the problem-solving process, as well as in the engineering design process?
    7·1 answer
  • Water (cp = 4180 J/kg·°C) enters the 2.5 cm internal diameter tube of a double-pipe counter-flow heat exchanger at 17°C at a rat
    7·1 answer
  • Under the normal sign convention, the distributed load on a beam is equal to the:_______A. The rate of change of the bending mom
    13·1 answer
  • 1. What are the usual symptoms of brake issues?​
    15·1 answer
  • What is it that makes a battery rechargeable? How is it different from a regular battery?
    14·2 answers
  • (CO 3) A nonrecursive filter may best be described as _____. Group of answer choices a filter whose current output depends on pa
    13·1 answer
  • Write down about the water source selection criteria​
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!