1 Shock-induced boundary layer separation in Round C-D nozzles Khairul Zaman Inlets and Nozzles...
-
Upload
dominick-shepherd -
Category
Documents
-
view
215 -
download
2
Transcript of 1 Shock-induced boundary layer separation in Round C-D nozzles Khairul Zaman Inlets and Nozzles...
1
Shock-induced boundary layer separation in Round C-D nozzles
Khairul Zaman
Inlets and Nozzles Branch, NASA GRC
Cleveland, OH 44135
Co-investigators: Timothy Bencic, Amy Fagan and Michelle Clem
Optics and Photonic Branch
Supported by
Commercial Supersonic Technology and
Transformative Tools and Technologies Projects
SWBLI Workshop, Dayton, OH
April 14-15, 2015
NASA Glenn Research Center
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
2
Background:
Shock-induced BL separation occurs in Convergent-divergent (C-D) nozzles when run in overexpanded condition. Such condition occurs, e.g., during certain flight regimes and also with rocket nozzles during start-up.
These flows are noisy and may involve detrimental unsteady loads.
As a first step in any analysis one requires the knowledge of mean shock location within the divergent section for a given nozzle pressure ratio (NPR).
NASA Glenn Research Center
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
3
Background:
Shock location within C-D nozzles have been studied in many previous investigations
Stodola experiment (1903) AndersonData with rocket nozzles Morrisette & Goldberg
1978
However, systematic database especially for lower design Mach number nozzles, typical of aircraft application, is lacking.
NASA Glenn Research Center
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
4
Objective:
Conduct experiment with a set of C-D nozzles to study steady-state shock-location as a function of ‘jet Mach number’ Mj (or NPR)
Analyze results vis-à-vis an available correlation and 1D theory
Experimental method: Pressure sensitive paint static pressure taps and shadowgraph
Note: Mj is ‘Mach number’ had the jet expanded fully for a given NPR.
NASA Glenn Research Center
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
AIAA Paper 2011-1031 Zaman/Bencic/Clem/FaganWith new data manuscript submitted for Journal publication
5
NASA Glenn Research Center
Experimental Facility
Open jet rig
MD=1.8 Noz
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
6
NASA Glenn Research Center
Facility:Nozzle characteristics
Nozzle Design Mach No., MD
Throat diameter Dt
Div. section length
M14 1.4 1.8952 1.832
M16 1.6 1.7900 2.382
M18 1.8 1.6702 2.630
M18L 1.8 1.6702 3.351
M22 2.2 1.4148 3.351
M28 2.8 1.0730 4.002
For these nozzles: exit diameter = 2”, Length = 7.5”
CAD image of M22
x (in)
r(i
n)
0 1 2 3 4 5 6 7 80.5
1
1.5
2
2.5
MD=
2.82.2
1.81.61.4
1.8L
Internal contours
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
7
NASA Glenn Research Center
FacilityAdditional nozzles
Large M21LgDE=3.5, Dt=2.567 Total length = 15Div sec length, L=4.2MD=2.1
Small M18SmGeometrically Similar to M18 DE=1.485MD=1.8
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
Mj [=] 0.4 – 1.7; ReD [=] 0.35x106 – 0.58x107 covered in experiment
8
NASA Glenn Research Center
Sample raw PSP dataM18 Nozzle
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
9
NASA Glenn Research Center
MJ
Wal
lPre
ssu
re,p
w/p
a
0.5 1 1.5
0.5
1
1.5
2 p1p2p3p4p5p6p7p8
PSP Data
MJ
Wal
lPre
ssu
re,p
w/p
a
0.5 1 1.5
0.5
1
1.5
2 p1p2p3p4p5p6p7p8
Data from 8 pressure taps
Comparison of PSP data with static pressure tap dataM18L
Pressure tap data PSP data
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
10
NASA Glenn Research Center
x / De
Wal
lPre
ssu
re,p
w/p
a
-1.5 -1 -0.5 00.5
1
1.5
2
2.5
MJ=0.4MJ=0.5MJ=0.6MJ=0.66MJ=0.7MJ=0.8MJ=0.9MJ=1.0MJ=1.1MJ=1.2MJ=1.3MJ=1.4MJ=1.5MJ=1.6
M18
x / De
Wal
lPre
ssu
re,p
w/p
a
-1.5 -1 -0.5 0
0.5
1
1.5
2
2.5
MJ=0.4MJ=0.5MJ=0.6MJ=0.7MJ=0.8MJ=0.9MJ=1.0MJ=1.1MJ=1.2MJ=1.3MJ=1.4MJ=1.5MJ=1.6MJ=1.66MJ=1.73
M18L
Profiles of wall pressure from PSP dataM18 and M18L
At separation, pw /pa 0.5 noted before Papamoschou & Johnson 2010
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
11
NASA Glenn Research Center
Morrisette & GoldbergNASA TP 1978
Reshotko & TuckerNACA TN 1955
Shock location vs. Mj
M18L
Mj
(x-x
*)/L
1 2 30
0.2
0.4
0.6
0.8
1
PSPPressure taps1-D theoryMG correlation
M18L
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
DesignN. Shock @exit
Throat choked
1-D
th
eory
12
NASA Glenn Research Center
MGRT correlation (Morrisette & Goldberg 1978 )Per Reshotko & Tucker (1955) (Eq. 3) assuming H1=1.286 and H2=2.2, M2 /M1=0.762 is obtained.
With M2= 0.762M1 find p2 /p1 (oblique shock Eqns. 128 and 132, Ames Table).
For a given x-location of the shock, find nozzle diameter at that x. Calculate Mach number assuming fully expanded flow up to this point. This is M1 (upstream of oblique shock). From M1, find corresponding wall pressure p1 /p0. Assuming p2 = pa , p0 /pa is found which yields Mj.
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
13
NASA Glenn Research Center
Shock location vs. Mj
M14 and M16
Mj
(x-x
*)/L
1 20
0.2
0.4
0.6
0.8
1M16
Mj
(x-x
*)/L
1 20
0.2
0.4
0.6
0.8
1M14
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
14
NASA Glenn Research Center
Shock location vs. Mj
M18 and M18L
Mj
(x-x
*)/L
1 2 30
0.2
0.4
0.6
0.8
1M18
Mj
(x-x
*)/L
1 2 30
0.2
0.4
0.6
0.8
1M18L
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
15
NASA Glenn Research Center
Shock location vs. Mj
M22 and M28
Mj
(x-x
*)/L
1 2 30
0.2
0.4
0.6
0.8
1M28
Mj
(x-x
*)/L
1 2 30
0.2
0.4
0.6
0.8
1M22
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
16
NASA Glenn Research Center
Mj
(x-x
*)/L
0.4 0.6 0.8 1 1.2 1.4 1.6 1.80
0.2
0.4
0.6
0.8
1
M14M16M18M18LM22M28
Shock location vs. Mj
For the six 2” nozzles
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
17
NASA Glenn Research Center
Shock location vs. Mj
For the six 2” nozzles
Mj / MD
(x-x
*)/L
0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
M14M16M18M18LM22M28tanh curve fit
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
y=(tanh(x-0.65))*0.5+0.5, x=Mj /MD , y=(x-x*)/L=5 for Mj/MD <0.65 and =8 for Mj/MD >0.65
18
NASA Glenn Research Center
Shock location vs. Mj
For the large and small nozzles
Mj / MD
(x-x
* )/L
0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
M18M18 SmallM22M21 Largetanh curve fit
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
19
NASA Glenn Research Center
Acceleration parameter K for different nozzles
Thus, BL before separation must be turbulent for M21Lg case
For other nozzles cannot be sure but also likely to be
turbulent
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
r /D
E
x/DE
K(=
U'/U
2x1
0-6)
-3 -2 -1 00
5
10
15
20M14M18M18LM28M21Lg
LaminarTurbulent
Narasimha & Sreenivasan1979
20
Conclusions:
Shock-induced boundary layer separation location documented for C-D nozzles of MD in the range 1.4-2.8.
PSP technique satisfactorily provided relative trends of wall pressure.
Data compared with a correlation from rocket nozzle literature; it agreed better for nozzles of higher MD but deviated at low MD.
All data correlated simply with the ratio of ‘jet Mach number’ to design Mach number (Mj /MD). A correlation equation is provided.
The correlation is found to be valid over a wide range of Re (0.35x106 – 0.58x107). An analysis indicates that the state of the boundary layer prior to separation is likely to be turbulent for all cases studied.
NASA Glenn Research Center
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
21
NASA Glenn Research Center
x / De
Wal
lPre
ssu
re,p
w/p
a
-1.5 -1 -0.5 00.5
1
1.5
2
2.5
3
3.5
MJ=0.4MJ=0.5MJ=0.6MJ=0.7MJ=0.8MJ=0.9MJ=1.0MJ=1.1MJ=1.2MJ=1.3MJ=1.4MJ=1.5MJ=1.6
M14
x / De
Wal
lPre
ssu
re,p
w/p
a
-1.5 -1 -0.5 0
0.5
1
1.5
2
2.5
3
MJ=0.4MJ=0.5MJ=0.6MJ=0.7MJ=0.8MJ=0.9MJ=1.0MJ=1.1MJ=1.2MJ=1.3MJ=1.4MJ=1.5MJ=1.6MJ=1.66MJ=1.73
M16
Profiles of wall pressure from PSP dataM14 and M16
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
Backup 1
22
NASA Glenn Research Center
x / De
Wal
lPre
ssu
re,p
w/p
a
-1.5 -1 -0.5 0
0.5
1
1.5
2
2.5
MJ=0.4MJ=0.5MJ=0.6MJ=0.7MJ=0.8MJ=0.9MJ=1.0MJ=1.1MJ=1.2MJ=1.3MJ=1.4MJ=1.5MJ=1.6MJ=1.66MJ=1.73
M22
x / De
Wal
lPre
ssu
re,p
w/p
a
-2 -1.5 -1 -0.5 0
0.5
1
1.5
2
MJ=0.4MJ=0.5MJ=0.6MJ=0.7MJ=0.8MJ=0.9MJ=1.0MJ=1.1MJ=1.2MJ=1.3MJ=1.4MJ=1.5MJ=1.6
M28
Profiles of wall pressure from PSP dataM22 and M28
SWBLI Wkshp, Dayton, April 14-15, 2015 Zaman/GRC
Backup 2
23
NASA Glenn Research Center
Minimum pressure at static pressure tapsM18L
(x - x*)/L
Min
imu
mp
w/p
a
Mjco
rres
po
nd
ing
tom
inim
um
pw/p
a
0 0.2 0.4 0.6 0.8 10.5
0.6
0.7
0.8
0
0.5
1
1.5
=>
<=
AIAA Paper 2011-1031 Zaman/Bencic/Clem/Fagan
Backup 3