Rocket Thermal Evaluation
RTE is a comprehensive Rocket
Thermal Evaluation computer code developed for NASA Lewis
Research Center, presently Glenn Research Center. The early version of the code
was distributed through NASA's COSMIC Library. For a
brief slide presntation of this code with some sample results click on this
text.
SUMMARY
RTE (Rocket Thermal
Evaluation) is a computer code for
three-dimensional thermal analysis of regeneratively
cooled rocket thrust chambers and nozzles. A unique feature of this code is
conjugating all thermal/fluids processes in the propulsion system in order to
obtain matched results for the thermal field. These thermal/fluids processes
include: convection and radiation heat transfer from hot combustion gases to
the liner of the engine; conduction heat transfer with walls; and convection to
the coolant. RTE uses an iterative marching scheme to match the heat flux and
temperature fields of these thermal processes. The program uses GASP (GAS
Properties), WASP (Water and Steam Properties) and a module for properties of
RP1 to evaluate coolant flow properties. Hence, it is capable of handling all
commonly used coolants in propulsion systems (e.g., H2, O2,
H2O, CH4, RP1, H2O2). CET (Chemical Equilibrium with
Transport Properties) code is used for evaluation of hot gas properties. The
inputs to RTE consist of the composition of fuel/oxidant mixtures and flow
rates, chamber pressure, coolant entrance temperature and pressure, dimensions
of the engine, materials and number of nodes in different parts of the engine.
It allows temperature variations in axial, radial and circumferential
directions and by implementing an iterative scheme, it provides a listing of
nodal temperatures, rates of heat transfer, and hot-gas and coolant thermal and
transport properties. The O/F (oxidant/fuel) ratio can be varied along the
thrust chamber. This feature allows the user to incorporate a non-equilibrium
model or an energy release model for the hot-gas-side. The mixture ratio at
each station can be calculated using ROCCID. Thermal
radiation from hot gases within the chamber is also included in the analysis.
The exchange factors for radiation calculations are evaluated using an external
module (RTE_RAD, Rocket Thermal Evaluation Discrete Exchange Factor), which can
be input to the main rocket thermal evaluation code.
This code can be
used for both regeneratively and radiatively
cooled engines. For regeneratively cooled engines,
the code can be used for one pass as well as pass-and-half cooling cycles.
Additionally, the blocked channel option allows a user to assess the thermal
performance of a regeneratively cooled engine when a
cooling channel is blocked. The user has the option of bypassing the
hot-gas-side calculations and directly inputting gas side fluxes. This feature
can be used to link RTE to a boundary layer program for the hot-gas-side heat
flux calculation. The procedure for linking RTE to a hot-gas side program, TDK (Two Dimensional Kinetics
Nozzle Performance Computer Program) is described in this manual.
To ease inputting
the large data sets needed to run the program a Graphic User Interface
(preprocessor) based on Excel is provided. A user can fill in engine
specifications in designated Excel cells and choose the right engine
information from combo boxes. Then by clicking on a command button, data from
the Excel interface would be transferred into RTEs input file. For a trial version of RTE's GUI click on this text. RTE
provides a number of output files, each provide useful information regarding
the engines thermal performance. The Graphic postprocessor of RTE is based on
Excel and Techplot software. It produces a number of
output files that can be processed by both Excel Tecplot
for temperature isotherms and graphic results.
To learn more about
Thermal Analysis of Regenenratively Cool Rocket
Engines you may enroll in the AIAA
webinar on Thermal Modeling and Regenerative Cooling of Rocket Engines.
More detailed
information on this program can be obtained from the following publications:
DiValentin, J., Naraghi, M.H.,
Effects of Cooling Channel Curvature and Aspect Ratio on the Coolant Secondary
Flow and Heat Transfer, to be presented at the 46th AIAA/ASME/SAE/ASEE Joint
Propulsion Conference, Nashville, Tennessee, July 25-28, 2010.
Jokhakar, J and Naraghi, M.H., A CFD-RTE Model for Thermal Analysis of Regeneratively Cooled Rocket Engines, AIAA paper
2008_128137, presented at the 44th AIAA/ASME/SAE/ASEE Joint Propulsion
Conference, Hartford, CT, July 21-23, 2008.
Foulon, M., and Naraghi, M.H., A Simple Approach for Thermal Analysis of
Regenerative Cooling of Rocket Engines, ASME paper IMECE2008-67988, presented
at the International Mechanical Engineering Congress, October 31-November 6,
2008.
Naraghi, M.H.N., Dunn, S.,
and Coats, D., Dual Regenerative Cooling Circuits for
Liquid Rocket Engines, AIAA-2006-4367, presented at the AIAA Joint Propulsion
Conference, Sacramento, California , July 2006.
Naraghi, M.H.N., Dunn, S.,
and Coats, D., Modeling of Radiative Heat Transfer
in Liquid Rocket Engines, AIAA-2005-3931, presented at the AIAA Joint
Propulsion Conference, Tucson, Arizona, July 2005.
Naraghi, M.H.N., Dunn, S.,
and Coats, D., A Model for Design and Analysis of Regeneratively
Cooled Rocket Engines, AIAA-2004-3852, presented at the AIAA/ASME/ASEE Joint
Propulsion Conference, Fort Lauderdale, Florida, July 11-14, 2004.
Naraghi, M.H.N., ``RTE - A Computer Code for Rocket Thermal
Evaluation," presented at the 1994 Thermal and Fluid Analysis Workshop,
Cleveland, Ohio, August 15-19, 1994.
Hammad, K.J., and Naraghi, M.H.N.,
``Radiative Heat Transfer in Rocket Thrust Chambers and Nozzles,'' AIAA
paper 89-1720, presented at the 24th AIAA Thermophysics
Conference in Buffalo, New York, June 12-14, 1989; also AIAA Journal of Thermophysics and Heat Transfer, Vol. 5, No. 3, pp.
327-334, 1991.
Naraghi, M.H.N., and Armstrong, E.S., ``Three Dimensional
Thermal Analysis of Rocket Thrust Chambers,'' AIAA paper 88-2648,
presented at the AIAA Thermophysics, Plasmadynamics and Lasers Conference, San Antonio, Texas, June
27-29, 1988.
Naraghi, M.H.N., and DeLise, J., ``
Conjugate Conductive, Convective and Radiative Heat Transfer in Rocket
Engines," ASME publication HTD-Vol. 307, pp. 65-79, Preceding of
the 30th National Heat Transfer Conference, Portland, Oregon, August 6-8, 1995.
If you are interested in obtaining a copy of the code please send an
e-mail to: mnaraghi@tara-technologies.com.
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