Motor Stirling
Motor Stirling
Motor Stirling
i W 5 A iivi-88897
N87-13359
Unclas
~ 1 1 8 5 44720
I t
\
f
a
Prepared for
Twenty-fourth Automotive Technology Development
sponsored by Society of Automotive Engineers
Dearborn, Michigan, October 27-30, 1986
.
DISCLAIMER
This report was prepared as an account of work sponsored by an agency
of the United States Government. Neither the United States Government
nor any agency thereof, nor any of their employees, makes any warranty,
express or implied, or assumes any legal liability or responsibility for the
accuracy, completeness, or usefulness of any information, apparatus,
product, or process disclosed, or represents that its use would not
infringe privately owned rights. Reference herein to any specific
commercial product, process, or service by trade name, trademark,
manufacturer, or otherwise, does not necessarily constitute or imply its
endorsement, recommendation, or favoring by the United States
Government or any agency thereof. The views and opinions of authors
expressed herein do not necessarily state or reflect those of the United
States Government or any agency thereof.
%odes are used for pricing all publications. The code is determined by
the number of pages in the publication. Information pertaining to the
pricing codes can be found in the current issues of the following
publications, which are generally available in most libraries: Energy
Research Abstracts (ERA); Government Reports Announcements and Index
(GRA and I); Scientific and Technrcal Abstract Reports (STAR), and
publication, NTIS-PR-360 available from NTlS at the above address.
DOE/NASA/50112-87
ASA TM-88891
Prepared for
Twenty-fourth Automotive Technology Development
sponsored by Society of Automotive Engineers
Dearborn, Michigan, October 27-30, 1986
.
PROGRESS OF STIRLING CYCLE ANALYSIS AND LOSS MECHANISM CHARACTERIZATION
Roy C. Tew, Jr.
National Aeronautics and Space Administration
Lewis Research Center
Cleveland, Ohio 44135
ABSTRACT
An assessment of Stirling engine thermodynamic modeling and design codes shows a general deficiency; this deficiency is due to poor
understanding of the fluid flow and heat
transfer phenomena that occur in the oscillating flow and pressure level environment
within the engines. Requirements for improving
modeling and design are discussed. Stirling
engine thermodynamic loss mechanisms are listed.
Several experimental and computational research
efforts now underway to characterize various
l o s s mechanisms are reviewed. The need for
additional experimental rigs and rig upgrades
is discussed. Recent developments and current
efforts in Stirling engine thermodynamic
modeling are also reviewed.
Several grants and contracts are now underway for characterizing one or more loss mechanisms. A review of these efforts follows. Those
efforts not specifically identified with Oak
Ridge or Argonne National Laboratories are being
managed by NASA Lewis. The NASA-managed efforts
are being funded by a combination of DOE,
Department of Defense, and NASA funds.
OSCILLATING FLOW TEST RIG FOR DEVELOPING
CORRELATIONS FOR ONE-DIMENSIONAL MODELS Sunpower, Inc., under a NASA Phase I Small
Business Innovation Research (SBIR) Contract,
designed an oscillating flow rig to be used in
measuring pressure drops through tubes and
matrices. A schematic of the rig is shown in
Fig. 1. A linear motor is used to drive the rig
at frequencies up to 120 Hz. The unique design
of the rig should allow accurate determination
of instantaneous mass flows and pressure drops.
It was designed to cover the entire range of
similarity parameters of interest in Stirling
engine design.
Sunpower is now building the rig and will
do the testing under a Phase I1 SBIR contract
(which began in April 1986).
Fabrication and
assembly of the rig is expected to be complete
in October 1986. System checkout and some initial testing should be complete by February
1987. The remaining one year and two months o f
the contract will be used to test and develop
pressure drop correlations for various Stirling
heat exchanger geometries. A unidirectional
Most Stirling models assume that temperature, pressure, and flow are uniform across a
cross section perpendicular to the flow axis.
Heat transfer and pressure drop are then calculated from experimental steady-flow correlations; this implies that the nonuniformities and
boundary-layer effects that contributed to the
form of the steady-flow correlations will make
the same contributions in the oscillating flow
and oscillating pressure level environment which
occurs inside Stirling engines.
The following " l o s s mechanisms'' may produce
significant impacts on the performance of
Stirling engines: (1) Effects of oscillating
flow/pressure level on pressure drop and radial
heat transfer in tubes, matrices, and area
transitions, ( 2 ) flow maldistributions--tube to
tube, manifold-regenerator interactions, area
transitions in general, ( 3 ) gas spring and
working space hysteresis (also called cyclic or
trshsient heat transfer) losses, ( 4 ) mixing
losses (adiabatic volumes, especially, increase
losses due to mixing of gases at two different
temperatures), (5) appendix gap heat losses
experienced in the clearance gap between the
cylinder wall and the piston, ( 6 ) leakage losses
(piston-cylinder, gas spring, free-piston
centering port flows), ( 7 ) conduction losses
(through metal conduction paths and through gas
inside the displacer), (8) enhanced axial
conductivity through the regenerator due to
LL.-~-
CCIS
---
?')
L-J
Iii contiast,
11. J.G. Slaby, "Overview of the 1986 FreePiston Stirline SP-100 Activities at the
NASA Lewis Research Center," 21st
Intersociety Energy Conversion Engineering
Conference, Vol. 1, Washington, D.C.:
American Chemical Society, 1986,
pp. 420-429.
REFERENCES
40. N.C.J.
10
SPRINGS
DRIVE MOTOR-\,
DRIVE SECTION
MAGNETS ,
,
GUIDE BEARING 1
.
PISTON
-/
DISPLACEMENT
SECTION
CLEARANCE SEAL-/-
PRESSURE
ENCLOSURE'
FIGURE 1.-
,,
. TEST SECTION
REFERENCE
PRESSURE
FIGURE2.- SCHEMATIC OF ARGONNE NATIONAL LABORATORY
REVERSING FLOW TEST F A C I L I T Y .
DRIVE WITH
SCOTCH YOKE
SYMMETRIC;IS
APPARATUS
NOTE THAT
ONLY HALF
IS SHOWN
HEAT
EXCHANGER
D = 0 04 M = 1.6 IN.
OSCILLATING FLOW
TEST RIG FOR OBTAINING MULTI-DIMENSIONAL MEASUREMENTS.
(A) REGENERATOR WITHMANIFOLD FLOW FROM SIDES SHOWS POSSIBLE MALDISTRIBUTIONS (DEPENDENT UPON FLOW DIRECTION).
. .. ... .
FIGURE4.-
W!?!!
.. . . . .
i '
COI ll FND
CYLINDER
HOT END
COMPRESSION
SPACE
EXPANS ION
SPACE
RECIPROCATING
MOTION
(A)
CONDUCTION HEAT
CONDUCTION HEAT-
RADIAL HEAT I N
rCONDUCTION
/' HEAT
-YNTHALPY
FLOW
CONVECTION
HEAT^
(PUMPING LOSS)
'-CONDUCTION
HEAT
FIGURE 5 .
CAT MAIN R N U :
INSTRUCTIONS
GENERATE MESH
STORE/RETRIEM
SOLVE PROBLEM
GLOSSARY
CHANGE DEFAULTS
OUTPUT
REFRESH SCREEN
END SESSION
CAT SUB-MENU
OPT IONS :
PLACE ELEMENTS
REMOVE ELEMENTS
I N I T IAL I ZE SYSTEM
ENTER LOGICAL STATE
2
iELP:
FIGURE 6.- A
.
.
COPY ELEMENT
SHOW PARAMETERS
EXPAND SCREEN
1. Report No.
NASA
3. Recipient's Catalog
No.
TM- 88891
5. Report Date
778- 35- 13
8. Performing Organization Report No.
7. Author@)
E-3302
Roy C . Tew, J r .
N a t i o n a l A e r o n a u t i c s and Space A d m i n i s t r a t i o n
Lewis Research Center
C l e v e l a n d , Ohio 44135
T e c h n i c a l Memorandum
R e p o r t No.
UOE/NASA/50112- 67
Prepared
F i n a l Rep0 r t . Prepared under I n t e r a g e n c y Agreement DE-AI01-85CE50112.
f o r Twenty - f o u r t h Automotive Technology Development sponsored by S o c i e t y o f
Au tomo t ive Engineers, Dearborn, Michigan, October 27-30, 1986.
I6 Abstract
S t i r l i n g engine; S t i r l i n g c y c l e ;
Space power
Unclassified
Unclassified - unlimited
STAR Category 85
DOE Category UC-96
Unclassified
*For sale by the National Technical Information Service, Springfield, Virginia 22161
22. Price'
A02