Thermodynamics Flashcards
Draw the T-s diagram for the following?
What cycle is this
Brayton Stationary
Draw the T-s diagram for the following?
What cycle is this?
Brayton Stationary
Draw the T-s diagram for the following?
What cycle is this?
Rankine
Draw the T-s diagram for the following?
What cycle is this?
Brayton Aerospace
What are the symbols for the following table?
What is the difference between T’ and T?
T’ is the isentropic temperature.
T is the real temperature.
How do we check if a nozzle is choked? And what do we do if it is/isn’t?
At the end of the nozzle, what 3 formulas are needed?
kg/m2 * m/s * m = kg/s
What are the two formulas to find the Mach number?
How do we calculate overall efficiency?
η = ηth x ηP
Draw the T-s diagram for the following?
What cycle is this?
Brayton Stationary
What is the formula for back work ratio?
BWR = Wc/Wt
Think back work = work done out the back to increase W(T)/W(Out)
How do we find mass flow rate if we’re given volumetric flow rate?
What is the equation for cycle efficiency?
η = Wnet / Qin
What is the trick for pumps?
Where do we find the data?
What do we have to remember?
Constant specific volume (m3/kg) as the water is as dense as possible? Density <=> 1 / specific volume
What is the COP for a refrigerator?
What is the COP for a heat pump?
Draw the T-s and P-v diagrams for a diesel engine?
What does 1 bar = to in kPa?
1 bar = 100 kPa
How do you calculate the mass fraction?
Degrees Celsius to Kelvin?
x + 273 = x K
Across a pump there is…?
Isentropic Compression
Across a turbine there is…?
Isentropic Expansion
How do we find the efficiency of a regenerator ηR?
Label the following jet engine diagram?
Draw the T-s diagram for a jet engine?
Draw it with real temperatures, hence the price chart movement
Draw the internal structure of a jet engine?
What is the formula for the efficiency of a compressor?
If in doubt, same as intake efficiency, as pre burner.
What must you remember with aerospace gas turbines?
That γ changes. 1.4 -> Burn -> 1.33
What do we need to do around the turbine and nozzle?
Stick to the formula sheet like glue.
Only use Isentropic T’5 to find P5. After that its real T only.
What formula can we use when we have the compressor ratio?
Note: not the compressor PRESSURE ratio
What can we do if constant pressure or constant volume to find q?
Const P, q = Cp(T2-T1)
Const V, q = Cv(T2-T1)
Both in the box on page 26
How can we find the specific volume v if,
Start?
Isentropic?
Constant P?
Constant V?
Start:
v = 1/ρ. And ρ = P/RT. So v = RT/P
Isentropic:
Use any compression ratios etc. So v2 = v1/rv
Constant P:
T3/T2 <=> v3/v2
Constant V:
v4 <=> v1
Draw the T-s and P-v diagrams for an Otto cycle?
Through a condenser. How do we find h?
We use the temperature to find it, not pressure.
Think condensers care about lowering temperatures. So use that instead of pressure.
So hf ~= hf(T)
