The objective is to establish a major experimental laboratory for studying fundamental processes such as mixing and combustion under liquid rocket engine conditions. The capability of this laboratory will include operation using a variety of fuel and oxidizer systems including liquid oxygen and liquid hydrocarbons. In addition to providing the proper facilities for supplying and controlling these fuels and oxidizers, a specific effort is being made to provide a state-of-the-art diagnostic capability for combustion measurements. In particular, optical and laser-based techniques are being emphasized for measurements of species, velocities, and spray characteristics

Kuo, Kenneth K.

Santoro, R. J.

English

NASA Technical Reports Server

PRESENTATION 2.2.2
N91-28223
CRYOGENIC COMBUSTION LABORATORY
637
https://ntrs.nasa.gov/search.jsp?R=19910018909 2020-03-19T17:28:14+00:00Z

CRYOGENIC COMBUSTION LABORATORY
FL J. Santoro and K. K. Kuo
Department of Mechanical Engineering
I. Research Objectives and Potential Impact on Propulsion
The objective of the current effort is to establish a major experimental laboratory
within the NASA Propulsion Engineering Research Center for studying fundamental
processes such as mixing and combustion under liquid rocket engine conditions. The
capability of this laboratory will include operation using a variety of fuel and oxidizer
systems including liquid oxygen and liquid hydrocarbons. In addition to providing the
proper facilities for supplying and controlling these fuels and oxidizers, a specific effort
is being made to provide a state-of-the-art diagnostic capability for combustion
measurements. In particular, optical and laser-based techniques are being
emphasized for measurements of species, velocity, temperature, and spray
characteristics.
The laboratory is to provide the necessary experimental capabilities for studies
conducted within the Center in the area of combustion instability, liquid jet breakup,
spray and droplet combustion, supercritical combustion phenomena, materials studies
and nozzle flow characterization. The flow and test stand designs emphasize an
approach which provides a flexible environment to accommodate a wide range of
experiments while providing for convenient future expansion as new research
directions emerge.
The Cryogenic Combustion Laboratory is intended to impact space propulsion
engineering in a two-fold manner. Experiments conducted in the laboratory are aimed
at providing benchmark data on a variety of important liquid rocket combustion
processes. A clear need for the development of such data bases for model validation
has been recommended in several recent JANNAF workshops. Sub-scale studies
utilizing laser-based diagnostic approaches offer a great potential for obtaining new
measurements under realistic operating conditions. It is precisely these types of
studies which the present laboratory effort is aimed at emphasizing.
The second impact of the current program involves the training of graduate
students who participate in the research projects conducted within the laboratory.
These students will be exposed to studies involving fuels and oxidizers similar to
present operational systems, investigated under conditions applicable to realistic
operation. The utilization of sophisticated diagnostic approaches for measurements
conducted under combustion conditions will also provide a valuable training
experience for the students who will assume positions in leading industrial and
government laboratories. Thus, the present laboratory development effort addresses
two of the major needs of space propulsion engineering: new fundamental studies of
liquid rocket engine phenomena and production of well.trained engineers to engage in
future space propulsion activities.
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PRECEDING PAGE BLANK NOT FILMED
I!. Current Status and Results
During the past year, significant progress has been made in the establishment of
the Cryogenic Combustion Laboratory, which had its first test firing using the gaseous
hydrogen and oxygen system. This test firing was achieved on schedule and marks
one of the major milestones in this project. Future work will proceed on a dual track
basis pursuing new experimental results while concurrently adding to the capabilities
of the laboratory. Specifically, liquid oxygen and hydrocarbon capabilities are planned
to be added in the near future.
The general arrangement and capabilities of the Cryogenic Combustion
Laboratory will be reviewed briefly in the remainder of this section. The Cryogenic
Combustion Laboratory, space for which was made available to the NASA Propulsion
Engineering Research Center in March, 1989, occupies a three-room complex which
includes a reinforced concrete test cell (see Figure 1). The test cell is complemented
by two adjacent rooms which serve as the instrumentation and control rooms. The
control room contains the equipment necessary to operate the test facility. This room
is isolated from the test cell during all test run sequences and is equipped with a
hydrogen detection system as an added level of safety. The entire system has been
designed to operate remotely using pneumatic and/or motorized actuated systems.
The design of the fuel and oxidizer supply system closely follows that of an existing
facility (Cell 21) located at the NASA Lewis Research Center (LeRC). Personnel at
NASA LeRC kindly provided facility drawings and parts lists which greatly aided in the
laboratory's development. Additional advice and guidance in the planning of the
laboratory has been provided by Marshall Space Flight Center, Rocketdyne, Air
Products, the Astronautics Laboratory (Air Force Systems Command) and Aerojet,
and their input is gratefully acknowledged.
The operation of the test facility presently allows for operation with gaseous
oxygen and gaseous fuels (hydrogen and methane have been used to date). The
maximum operating pressure is approximately 1500 psi, a limit imposed by the
present fire valve. The flow system has been designed to provide a maximum flow
rate of 0.1 Ibs/s of oxygen. This has been decided to be adequate for the present
sub-scale studies for which this laboratory is intended. The sequencing of all
combustion test firing is controlled by a Modicon sequencer which provides real time
fault detection for run monitoring and shutdown. System testing of the entire flow
system was achieved using a rocket igniter constructed by the NASA LeRC. This unit
has been widely used at the NASA LeRC and represented a known test engine from
which to evaluate the operation of gaseous flow system and control equipment.
Successful firings of this igniter occurred near the end of December, 1989, and have
periodically continued through March, 1990. Both hydrogen/oxygen and
methane/oxygen test runs have been conducted. This extensive series of tests has
provided a suitable basis for assuring the adequacy of the safety systems, run
procedures and general operation of the laboratory. Figure 2 shows a photograph of
one of the test firings of the rocket igniter burning methane/oxygen.
640
Propellant
storage area
Gas sensors
and additional
-] data systems
Sequencer and
cDoatmapautCC'ruis/ti°n t_ /_ bort monitor
_-_ k___ I Control panal
iii
Instrumentation I Test cell
room
| II tl°w'°ntr°l
]1 I I_11 Teststa,,,_
LI II _11 _°°roo,,o,
Figure 1. Schematic representation of the Cryogenic Combustion Laboratory
Complex: TestCell, Instrumentation Room and Control Room
641
ORICIN,e,L PAGE
_LACK AND WHILE PHOTOGRAPH
Figure 2: Rocket Test Igniter Firing: Methane oxygen test at an
equivalence ratio of 0.56. Oxidizer mass flow rate of 0.01
lbm/sec, fuel mass flow rate of 0.0014 lbm/s. Chamber
pressure 85 psia.
C':_i_iN#,LPAGE IS
0;_" POOR QUALITY
642
In addition to the progress achieved in the gaseous flow systems for the
laboratory, efforts have been initiated to add a liquid oxygen capability. A suitable
cryogenic oxygen storage tank has been obtained. This tank was originally
associated with Prof. L. Crocco's laboratory at Princeton University and has been
kindly made available to the NASA Propulsion Engineering Research Center by
Princeton. The initial design plans for the liquid oxygen flow system have been
completed and the components are presently being ordered.
Future plans for experiments using the Cryogenic Combustion Laboratory include
imaging studies of the combustion processes within the rocket chamber. These
studies will initially concentrate on planar (i.e. two-dimensional) imaging of OH radical
concentration profiles in a hydrogen/oxygen rocket. Further studies of spray
combustion processes are also planned using both planar and point measurement
techniques. Efforts to establish the necessary diagnostic capabilities have also
progressed substantially. Both a pulsed Nd-Yag and a cw argon ion laser system
have been acquired during the last year for use in these studies. Diagnostics for
providing two-dimensional imaging of droplets in a combusting environment are
presently being developed in a separate laboratory for use with these lasers.
Additionally, a phase doppler particle analyzer has recently been added for additional
droplet sizing capabilities. A dye laser will also be available shortly to give additional
wavelength selection capabilities.
In summary, the first phase of the Cryogenic Combustion Laboratory has been
successfully completed. Progress on applying the present test capability to new
measurements and studies has been initiated. Planning to complete the second major
operational goal, liquid oxygen capability, is proceeding on schedule. Additionally, a
solid diagnostic basis is being developed to complement the test capability of the
laboratory with state-of-the-art diagnostic techniques.
643
IlL Proposed Work for Coming Year
During the coming year, the proposed work will focus on augmenting the
Cryogenic Combustion Laboratory to include liquid oxygen capability. The present
design specifies a LOX mass flow rate of 1 Ib/s which significantly increases the
present capabilities over that of the gaseous oxygen system. The intent of achieving
this flow rate is based on a desire to adequately study liquid rocket injector elements.
Both uni-element and multi-element (three to five elements) studies should be feasible
with the planned flow system. Initial testing of this system will be accomplished using
the current hydrogen fuel system, and initial tests are planned for the end of the
present calendar year.
As a concurrent effort, the first two of a series of laser diagnostic techniques are
presently under development. These techniques involve planar laser imaging of OH
and spray visualization and sizing. Both techniques are intended to provide spatially
extensive (i.e. two-dimensional fields) under high temporal resolution conditions. The
OH diagnostics will utilize the Center's present Nd-Yag laser in conjunction with a
recently acquired dye laser and wavelength doubling system. The necessary data
acquisition and solid-state camera system are presently being specified. Initial
development of the OH visualization system will be accomplished using a flat flame
burner before application to a uni-element injector, rocket combustor environment.
Presently, several design approaches are being pursued for developing an
appropriate optically accessible rocket chamber. Initial measurements of OH in such
a rocket combustor are planned for the coming year of the program. These initial
rocket studies will utilize the present gaseous hydrogen and oxygen flow system. Use
of this system provides the simplest system for achieving the planned measurements,
eliminating interference from droplets or soot particles. The intention of the present
program is to examine the OH distribution as a qualitative indication of the combustion
zone distribution in the combustor. Future work is intended to examine the effects of
oscillating pressure fields on that distribution. However, these efforts go beyond the
present program for the Cryogenic Combustion Laboratory which emphasizes
development of the basic laboratory and diagnostic capability to support the space
propulsion research interests of the Center.
In a similar approach, a planar laser imaging approach for spray diagnostics is
being developed as part of a separate program on rocket spray combustion
phenomena (H.R. Jacobs and R.J. Santoro, "Spray Combustion Under Oscillatory
Pressure Conditions".) This technique utilizes the ratio of scattered light obtained at
two polarization orientations to provide a measure of the droplet size. Evaluation of
this diagnostic approach is presently proceeding in a non-combusting environment.
Based on the results of these studies, this approach will be implemented for the study
of liquid oxygen sprays in coaxial injector elements.
In summary, the proposed effort for the current year involves both a continued
development of the Cryogenic Combustion Laboratory along with the initiation of basic
propulsion studies in simple rocket combustors. These developments represent the
realization of a laboratory capability needed for f_ure Center research efforts.
644


Cryogenic combustion laboratory

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