Steady Flow Rate

Question 1

what is the steady flow energy equation

Answer 1

ΔEnergy = system + kinetic + potential

Q - W = ṁ(Δh + (Δc^2)/2 + g(Δx)

ṁ = mass flow rate
h = specific enthalpy
c = fluid velocity
x = height

Question 2

definition of enthalpy + equation

Answer 2

measure of energy in a thermodynamic system
h = U +pV

U = initial energy
p = pressure
V = volume

Question 3

assumptions when using the steady flow equation

Answer 3

• Mass flow is constant
• Any heat or work crossing the boundary does so at a uniform rate

Question 4

state assumptions made and examples: Q = ṁ(Δh)

Answer 4

• constant volume
• no work is done
• little to no velocity so kinetic energy is negligible
  example = boiler

Question 5

state assumptions made and examples: (Δc^2)/2 = Δh

Answer 5

• equation for nozzle (negative diffuser)
• no gain or loss in heat
• constant volume

Question 6

state assumptions made and examples: W= Δh

Answer 6

• process is assumed to be adiabatic
• velocity assumed to be constant

example = turbine + compresser

Question 7

equation for efficiency

Answer 7

= work done / heat supplied

= W/Q
= (Qs - Qr) / Qs

Question 8

What is the relationship between Q and T on the absolute temperature scale

Answer 8

They are proportional to each other

Question 9

What is COP

Answer 9

co efficient of performance
COP = Q/W