In this study, the viability, performance, and characteristics of a turbojet-to-turbofan conversion through the use of a continuously variable transmission (CVT) are investigated. By an in-house thermodynamic simulation code, the performance of the simple cycle turbojet, a direct shaft joined turbofan, and a CVT coupled turbofan with variable bypass is contrasted. The baseline turbojet and turbofan findings are validated against a commercial software. The comparison indicates high quantitative agreement. Analyzing the results of the turbofan engine equipped with a variable bypass and CVT, it is observed that both the thrust and the efficiency are increased. The augmented thrust is observed to be an artifact of enhanced component matching and wider operational range introduced by variable bypass capability. On the other hand, the introduction of CVT contributes to the reduction in fuel consumption. Therefore, the current research suggests that adaptation of a micro-turbojet into a variable cycle micro-turbofan will greatly improve the performance and efficiency of existing engines, in addition to providing a pathway toward extended use in various applications.

References

References
1.
Nelson
,
J.
, and
Dix
,
D. M.
,
2003
, “
Development of Engines for Unmanned Air Vehicles: Some Factors to Be Considered
,” Institute for Defense Analyses, Alexandria, VA,
IDA Document D-2788
.http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA412680
2.
Gunston
,
B.
,
1998
, World Encyclopaedia of Aero Engines: All Major Aircraft Power Plants, From the Wright Brothers to the Present Day, Haynes Publishing, Yeovil, UK.
3.
Saravanamuttoo
,
H.
,
Rogers
,
G. F.
, and
Cohen
,
H.
,
2001
,
Gas Turbine Theory
,
Pearson Education
, Upper Saddle River, NJ.
4.
Sellers
,
J.
, and
Daniele
,
C.
,
1975
, “
DYNGEN: A Program for Calculating Steady-State and Transient Performance of Turbojet and Turbofan Engines
,” National Aeronautics and Space Administration, Washington, DC,
Report No. NASA TN D-7901
.http://ntrs.nasa.gov/search.jsp?R=19750017548
5.
Chiang
,
H.-W. D.
,
Hsu
,
C.-N.
,
Lai
,
A.
, and
Lin
,
R.
,
2002
, “
An Investigation of Steady and Dynamic Performance of a Small Turbojet Engine
,”
ASME
Paper No. GT2002-30577.
6.
Lichtsinder
,
M.
, and
Levy
,
Y.
,
2002
, “
Steady-State and Transient Performance of Single-Spool Turbojets Using Novel matlab Program
,”
Int. J. Turbo Jet Engines
,
19
(
3
), pp.
139
156
.
7.
Dufour
,
G.
,
Carbonneau
,
X.
,
Cazalbou
,
J.-B.
, and
Chassaing
,
P.
,
2006
, “
Practical Use of Similarity and Scaling Laws for Centrifugal Compressor Design
,”
ASME
Paper No. GT2006-91227.
8.
Kurzke
,
J.
, and
Riegler
,
C.
,
2000
, “
A New Compressor Map Scaling Procedure for Preliminary Conceptional Design of Gas Turbines
,”
ASME
Paper No. 2000-GT-0006.
9.
Michel
,
U.
,
2011
, “
The Benefits of Variable Area Fan Nozzles on Turbofan Engines
,”
AIAA
Paper No. 2011-226.
10.
McBride
,
B. J.
,
Zehe
,
M. J.
, and
Gordon
,
S.
,
2002
, “
NASA Glenn Coefficients for Calculating Thermodynamic Properties of Individual Species
,” National Aeronautics and Space Administration, John H. Glenn Research Center at Lewis Field, Cleveland, OH,
Report No. NASA TP-2002-211556
.http://ntrs.nasa.gov/search.jsp?R=20020085330
11.
Lichtsinder
,
M.
, and
Levy
,
Y.
,
2006
, “
Jet Engine Model for Control and Real-Time Simulations
,”
ASME J. Eng. Gas Turbines Power
,
128
(
4
), pp.
745
753
.
12.
Giffin
,
R.
,
Parker
,
D.
, and
Dunbar
,
L.
,
1971
, “
Experimental Quiet Engine Program Aerodynamic Performance of Fan A
,” NASA, Washington, DC, Report No. NASA-CR-120858.
13.
Nissan, 2015, “
XTRONIC CVT
,”
Nissan Motor Company
, Kanagawa Prefecture, Japan.http://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/cvt.html
14.
Smithson
,
R.
,
Pohl
,
B. P.
,
Lohr
,
C. B.
,
Solis
,
J.
,
Nielsen
,
T.
,
McBroom
,
S. T.
, and
Munguia
,
N.
,
2012
, “
Auxiliary Power Unit Having a Continuously Variable Transmission
,”
U.S. Patent No. US8845485 B2
.https://www.google.com/patents/US8845485
15.
Youssef
,
N.
,
2012
, “
Gas Turbine Aircraft Engine With Power Variability
,”
U.S. Patent No. US8181442 B2
.https://www.google.com/patents/US8181442
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