1 Challenge the future
Wave speed measurements in non-ideal compressible flows
Using the Flexible Asymmetric Shock Tube (FAST)
Tiemo Mathijssen1, M. Gallo1, E. Casati1, A. Guardone2, P. Colonna1 1 Delft University of Technology, Propulsion and Power 2 Politecnico di Milano, Department of Aerospace Science
2 Challenge the future
Outline
• Non-ideal compressible fluid dynamics (NICFD)
• Flexible Asymmetric Shock Tube (FAST) setup
• N2 measurements
• D6 siloxane measurements
• Conclusions & Future Work
3 Challenge the future
Example: propagation of a weak pressure wave (piston)
x
P t t=
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Shock formation and the role of Γ
2 2
2
2
wave propagation speed:
sound speed: s
s
w u cPc vv
v v cdw dPc c v
= +
∂ ≡ − ∂
∂ = − ∂
Fndmtl. derivative: 1s
vdw dPc
v cc v
∂ Γ ≡ −
⇒ =
Γ
∂
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Wave propagation speed
Γ>1
Flow speed
Sound speed
Wave speed
+
=
Ideal gas
6 Challenge the future
Wave propagation speed
Γ>>1 Γ>1
Flow speed
Sound speed
Wave speed
+
=
Ideal gas
7 Challenge the future
Wave propagation speed
Γ>>1 Γ>1 0<Γ<1
Flow speed
Sound speed
Wave speed
+
=
Ideal gas
8 Challenge the future
Wave propagation speed
Γ>>1 Γ>1 0<Γ<1
Flow speed
Sound speed
Wave speed
+
=
Ideal gas
Γ=0
9 Challenge the future
Wave propagation speed
Γ>>1 Γ>1 0<Γ<1 Γ<0
Flow speed
Sound speed
Wave speed
+
=
Ideal gas
Γ=0
10 Challenge the future
Wave propagation speed
Γ>>1 Γ>1 0<Γ<1 Γ<0
Flow speed
Sound speed
Wave speed
+
=
Ideal gas
Γ=0
NICFD NICFD
11 Challenge the future
Wave propagation speed
Γ>>1 Γ>1 0<Γ<1 Γ<0
Flow speed
Sound speed
Wave speed
+
=
Ideal gas
Γ=0
NICFD NICFD Non- classical
12 Challenge the future
Γ and shockwaves
Compression shock Rarefaction (isentropic) fan Stationary wave profile
Compression (isentropic) fan Rarefaction shock
0Γ>
0Γ=
0Γ<
0 00 0
dP dwdP dw
> ⇒ >< ⇒ <
0dP dw∀ ⇒ =
0 00 0
dP dwdP dw
> ⇒ << ⇒ >
Non classical
Classical
13 Challenge the future
Γ in complex organic fluids
T Γ<0
s
Γ<1
14 Challenge the future
Γ in complex organic fluids
T Γ<0
s
Γ<1 Γ<0
15 Challenge the future
Γ in complex organic fluids
T Γ<0
s
Γ<1 Γ<0
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Γ in complex organic fluids
T Γ<0
s
Γ<1 Γ<0
17 Challenge the future
ORC windtunnel nozzle design
A. Guardone, A.Spinelli, V. Dossena, “Influence of Molecular Complexity on Nozzle Design for an Organic Vapor Wind Tunnel”, J. Eng. Gas Turbines Power 135(4), 042307, Mar 18, 2013.
18 Challenge the future
Inflow:
• M = 1.6
• Same reduced tmd state
P. Colonna and S. Rebay, ``Numerical simulation of dense gas flows on unstructured grids with an implicit high resolution upwind Euler solver,'' Int. J. Numer. Meth. Fl., vol. 46, no. 7, pp. 735-765, 2004.
Non classical effect in a “simplified” turbine cascade
Steam
Siloxane
19 Challenge the future
Shock-free ORC turbine: Compression fan!
B. P. Brown and B. M. Argrow, ``Application of Bethe-Zel'dovic-Thompson fluids in Organic Rankine Cycle Engines,'' J. Propul. Power., vol. 16, pp. 1118-1123, November-December 2000.
T
s
Γ<0
150 kW ORC turbine
20 Challenge the future
Experiments in NICFD • Borisov (1983)
• Argrow (2000)
• TU Delft (2014-2015)
• Milano (2014-2015)
Delft: Flexible Asymmetric Shock Tube (FAST)
Milano: Trova
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21
The FAST: the concept
• Ludwieg Tube
• speed-of-flight measurement of wave
• D6 Siloxane as working fluid
22 Challenge the future
22
The FAST: the concept
• Ludwieg Tube
• speed-of-flight measurement of wave
• D6 Siloxane as working fluid
23 Challenge the future
The FAST: realization
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D6 experiment Te
mpe
ratu
re [
ºC]
Time [hours]
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Tsat deviation at low pressure
D6 experiment Te
mpe
ratu
re [
ºC]
Time [hours]
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Start heating Charge tube & Reference tube
Tsat deviation at low pressure
D6 experiment Te
mpe
ratu
re [
ºC]
Time [hours]
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Start heating Charge tube & Reference tube
Start heating Vapour generator
Tsat deviation at low pressure
D6 experiment Te
mpe
ratu
re [
ºC]
Time [hours]
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Start heating Charge tube & Reference tube
Start heating Vapour generator
Opening manual valve MV-4
Tsat deviation at low pressure
D6 experiment Te
mpe
ratu
re [
ºC]
Time [hours]
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Start heating Charge tube & Reference tube
Start heating Vapour generator
Opening manual valve MV-4
Tsat deviation at low pressure
D6 experiment
Slow heating to avoid condensation
Tem
pera
ture
[ºC
]
Time [hours]
30 Challenge the future
Start heating Charge tube & Reference tube
Start heating Vapour generator
Opening manual valve MV-4
Tsat deviation at low pressure
Opening FOV
D6 experiment
Slow heating to avoid condensation
Tem
pera
ture
[ºC
]
Time [hours]
31 Challenge the future
Nitrogen experiment 𝑤𝑤 =
∆𝑥𝑥∆𝑡𝑡
Δx = 0.3m
Pressure 4.01 bar
Temperature 25.8 °C
Γ 1.2
32 Challenge the future
Nitrogen experiment
PT1 PT2
𝑤𝑤 =∆𝑥𝑥∆𝑡𝑡
Δx = 0.3m
Pressure 4.01 bar
Temperature 25.8 °C
Γ 1.2
33 Challenge the future
Nitrogen experiment
PT1 PT2
𝑤𝑤 =∆𝑥𝑥∆𝑡𝑡
Δx = 0.3m
Pressure 4.01 bar
Temperature 25.8 °C
Γ 1.2
34 Challenge the future
Nitrogen experiment
PT1 PT2
Δt1
Δt2
Δt3
𝑤𝑤 =∆𝑥𝑥∆𝑡𝑡
Δx = 0.3m
Pressure 4.01 bar
Temperature 25.8 °C
Γ 1.2
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Nitrogen experiment
Speed of sound
Theory 350 m/s
Shifted curve
349 m/s
Linear fit 346 m/s
Average accuracy 5% wave speed 1-2% speed of sound
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D6 siloxane experiment
Speed of sound Theory 94.8 m/s
Shifted curve 93.9 m/s
Linear fit 96.9 m/s
Pressure 1.27 bar
Temperature 298 °C
Γ 0.91
8% wave speed 1.6% speed of sound
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Conclusions & Future work
• Non-Ideal Compressible Fluid Dynamics
• FAST Ludwieg tube commissioned
• Pressure and Temperature regulated independently
• Measurements of Wave propagation speed • 5% - 8% accuracy
• Method to determine speed of sound
• 1% - 2% accuracy
• Next: Measurements at lower Γ
38 Challenge the future
Thank you for your attention!
Questions?
T. Mathijssen, M. Gallo, E. Casati, N.R. Nannan, C. Zamfirescu, A. Guardone, P. Colonna, “The flexible asymmetric shock tube (FAST): a Ludwieg tube facility for wave propagation measurements in high-temperature vapours of organic fluids”, Exp. In Fluids 56:195, October 2015
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