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Group of preprogrammed plug-in cards and control module converts breadboard control electronics of actuator assembly to actuator tester. System utilizes electronic control, and hydraulic systems of breadboard actuator into which it is installed.
The nozzle is a major component of a rocket engine, having a significant influence on the overall engine performance and representing a large fraction of the engine structure. The design of the nozzle consists of solving simultaneously two different problems: the definition of the shape of the wall that forms the expansion surface, and the delineation of the nozzle structure and hydraulic system. This monography addresses both of these problems. The shape of the wall is considered from immediately upstream of the throat to the nozzle exit for both bell and annular (or plug) nozzles. Important aspects of the methods used to generate nozzle wall shapes are covered for maximum-performance shapes and for nozzle contours based on criteria other than performance. The discussion of structure and hydraulics covers problem areas of regeneratively cooled tube-wall nozzles and extensions; it treats also nozzle extensions cooled by turbine exhaust gas, ablation-cooled extensions, and radiation-cooled extensions. The techniques that best enable the designer to develop the nozzle structure with as little difficulty as possible and at the lowest cost consistent with minimum weight and specified performance are described.
An apparatus and method are described for reproducibly analyzing trace amounts of a large number of organic volatiles existing in a gas sample. Direct injection of the trapped volatiles into a cryogenic percolum provides a sharply defined plug. Applications of the method include: (1) analyzing the headspace gas of body fluids and comparing a profile of the organic volatiles with standard profiles for the detection and monitoring of disease; (2) analyzing the headspace gas of foods and beverages and comparing the profile with standard profiles to monitor and control flavor and aroma; and (3) analyses for determining the organic pollutants in air or water samples.
Research programs were conducted to investigate experimentally the aeroacoustic characteristics of scale model, inverted-velocity profile coannular nozzles. These programs include studies of unsuppressed configurations with and without center plugs over a variety of radius ratios and area ratios. Also included are suppressed configurations, the effect of ejectors, and some simulated flight effects. Unsuppressed inverted-velocity profile coannular nozzles seem to allow jet mixing noise compliance with present FAR-36 regulations when applied to supersonic cruise aircraft engine cycles. Simulated flight tests suggest that the aeroacoustic benefits of the inverted-velocity profile coannular nozzles would be maintained in flight.
Circuitry for maintaining an arc or spark across a spark gap for a desired length of time is disclosed. A high voltage, direct current source is connected in series with a secondary winding of a high voltage, stepup transformer or coil and a spark gap such as a spark plug for example. The high voltage source may be on continuously or may be turned on and off by a control circuit such as a solid state switch which is, in turn, responsive to a timing device such as a set of ignition contact points or a magnetic pulse generator operating in synchronism with a spark ignition engine. The timing device also provides signals to a current switching circuit which interrupts, current flow through a primary winding of the high voltage coil at the prescribed time that a spark is desired at the spark gap.
A computer coded Lagrangian marker particle in Eulerian finite difference cell solution to the three dimensional incompressible mass transport equation, Water Advective Particle in Cell Technique, WAPIC, was developed, verified against analytic solutions, and subsequently applied in the prediction of long term transport of a suspended sediment cloud resulting from an instantaneous dredge spoil release. Numerical results from WAPIC were verified against analytic solutions to the three dimensional incompressible mass transport equation for turbulent diffusion and advection of Gaussian dye releases in unbounded uniform and uniformly sheared uni-directional flow, and for steady-uniform plug channel flow. WAPIC was utilized to simulate an analytic solution for non-equilibrium sediment dropout from an initially vertically uniform particle distribution in one dimensional turbulent channel flow.
The design requirements for a Programmable Data Communications Controller (PDCC) that reduces the difficulties in attaching data terminal equipment to a computer are presented. The PDCC is an interface between the computer I/O channel and the bit serial communication lines. Each communication line is supported by a communication port that handles all line control functions and performs most terminal control functions. The port is fabricated on a printed circuit board that plugs into a card chassis, mating with a connector that is joined to all other card stations by a data bus. Ports are individually programmable; each includes a microprocessor, a programmable read-only memory for instruction storage, and a random access memory for data storage.
A numerical program was developed to compute transient laminar flows in two dimensions including multicomponent mixing and chemical reaction. The program can compute both incompressible flows and compressible flows at all speeds, and it is applied to describe transient and steady state solutions for low subsonic, coaxial entry, tue flows. Single component, nonreacting flows comprise most of the solutions, but one steady state solution is presented for trace concentration constituents engaging in a second order reaction. Numerical stability was obtained by adding at each calculation point a correction for numerical diffusion errors caused by truncation of the Taylor series used to finite difference the conservation equations. Transient computations were made for fluids initially at rest, then subjected to step velocity inputs that were uniform across each region of the entry plane and were held constant throughout the computation period. For center tube to annulus velocity ratios of 0.5 and 2.0, the bulk fluid in the tube initially moved in plug flow, but strong radial flows developed near the injection plane which moved the fluid into the high shear region between the jets and away from the tube wall.
An empirical model for predicting the noise from inverted-velocity-profile coaxial or coannular jets is presented and compared with small-scale static and simulated flight data. The model considered the combined contributions of as many as four uncorrelated constituent sources: the premerged-jet/ambient mixing region, the merged-jet/ambient mixing region, outer-stream shock/turbulence interaction, and inner-stream shock/turbulence interaction. The noise from the merged region occurs at relatively low frequency and is modeled as the contribution of a circular jet at merged conditions and total exhaust area, with the high frequencies attenuated. The noise from the premerged region occurs at high frequency and is modeled as the contribution of an equivalent plug nozzle at outer stream conditions, with the low frequencies attenuated.
Dry coal feeder systems developed for pressurized conversion processes were carried through a laboratory scale development program. These concepts include: (1) a centrifugal solids feeder; (2) a fluidized piston feeder; (3) a linear pocket feeder; and (4) a compacted coal plug feeder. Results of laboratory model testing of all concepts are reviewed.
A JT8D-17R engine with inverted primary and fan flows was tested under static conditions as well as in the NASA Ames 40 by 80 Foot Wind Tunnel to determine static and flight noise characteristics, and flow profile of a large scale engine. Test and analysis techniques developed by a previous model and JT8D engine test program were used to determine the in-flight noise. The engine with inverted flow was tested with a conical nozzle and with a plug nozzle, 20 lobe nozzle, and an acoustic shield. Wind tunnel results show that forward velocity causes significant reduction in peak PNL suppression relative to uninverted flow. The loss of EPNL suppression is relatively modest. The in-flight peak PNL suppression of the inverter with conical nozzle was 2.5 PNdb relative to a static value of 5.5 PNdb. The corresponding EPNL suppression was 4.0 EPNdb for flight and 5.0 EPNdb for static operation. The highest in-flight EPNL suppression was 7.5 EPNdb obtained by the inverter with 20 lobe nozzle and acoustic shield. When compared with the JT8D engine with internal mixer, the inverted flow configuration provides more EPNL suppression under both static and flight conditions.
A cycle timer was developed to assist the driver of an electric vehicle in more accurately following and repeating SAE driving schedules. These schedules require operating an electric vehicle in a selected stop-and-go driving cycle and repeating this cycle pattern until the vehicle ceases to meet the requirements of the cycle. The heart of the system is a programmable read-only memory (PROM) that has the required test profiles permanently recorded on plug-in cards, one card for each different driving schedule. The PROM generates a direct current analog signal that drives a speedometer displayed on one scale of a dual movement meter. The second scale of the dual movement meter displays the actual speed of the vehicle as recorded by the fifth wheel. The vehicle operator controls vehicle speed to match the desired profile speed. The PROM controls the recycle start time as well as the buzzer activation. The cycle programmer is powered by the test vehicle's 12-volt accessory battery, through a 5-volt regulator and a 12-volt dc-to-dc converter.
The results of a static acoustic and aerodynamic performance, model-scale test program on coannular unsuppressed and multielement fan suppressed nozzle configurations are summarized. The results of the static acoustic tests show a very beneficial interaction effect. When the measured noise levels were compared with the predicted noise levels of two independent but equivalent conical nozzle flow streams, noise reductions for the unsuppressed coannular nozzles were of the order of 10 PNdB; high levels of suppression (8 PNdB) were still maintained even when only a small amount of core stream flow was used. The multielement fan suppressed coannular nozzle tests showed 15 PNdB noise reductions and up to 18 PNdB noise reductions when a treated ejector was added. The static aerodynamic performance tests showed that the unsuppressed coannular plug nozzles obtained gross thrust coefficients of 0.972, with 1.2 to 1.7 percent lower levels for the multielement fan-suppressed coannular flow nozzles. For the first time anywhere, laser velocimeter velocity profile measurements were made on these types of nozzle configurations and with supersonic heated flow conditions. Measurements showed that a very rapid decay in the mean velocity occurs for the nozzle tested.
A controlled growth, heat-flow and cool-down process is described that yielded silicon with a high degree of single crystallinity. Even when the seed melted out, very large grains formed. Solar cell samples made from cast material yielded conversion efficiency of over 9%. Representative characterizations of grown silicon demonstrated a dislocation density of less than 100/sq cm and a minority carrier diffusion length of 31 micron. The source of silicon carbide in silicon ingots was identified to be from graphite retainers in contact with silica crucibles. Higher growth rates were achieved with the use of a graphite plug at the bottom of the silica crucible.
A reaction control system nozzle block is provided for testing the response characteristics of space vehicles to a variety of reaction control thruster configurations. A pressurized air system is connected with the supply lines which lead to the individual jet nozzles. Each supply line terminates in a compact cylindrical plenum volume, axially perpendicular and adjacent to the throat of the jet nozzle. The volume of the cylindrical plenum is sized to provide uniform thrust characteristics from each jet nozzle irrespective of the angle of approach of the supply line to the plenum. Each supply line may be plugged or capped to stop the air supply to selected jet nozzles, thereby enabling a variety of nozzle configurations to be obtained from a single model nozzle block.
The author has identified the following significant results. An extension of the trace of the Chaman-Nushki fault was detected and delineated for 42 km, as was the Ornach-Nal fault for 170 km. Two structural intersections responsible for restricted movements in particular segments of the Chaman-Nushki fault were detected and interpreted. The newest and youngest fault named the Quetta-Mustung-Surab system was delineated for 580 km. The igneous complex of the Lasbela area was interpreted and differentiation was made between ultramafic complex, mafic complex, and basaltic lava flows. One oblong feature was also found which was interpreted as a porphyritic basalt plug.
The present understanding of spray combustion in rocket engine, gas turbine, Diesel engine and industrial furnace applications is reviewed. In some cases, spray combustion can be modeled by ignoring the details of spray evaporation and treating the system in the same manner as a gaseous diffusion flame; however, in many circumstances, this type of simplification is not adequate and the turbulent two-phase flow must be considered. The behavior of individual droplets is a necessary component of two-phase models and recent work on transient droplet evaporation, ignition and combustion is considered, along with a discussion of important simplifying assumptions involved with modeling these processes. Methods of modeling spray evaporation and combustion processes are also discussed including: one-dimensional models for rocket engine and prevaporized combustion systems, lumped zone models (utilizing well-stirred reactor and plug flow regions) for gas turbine and furnace systems, locally homogeneous turbulent models, and two-phase models. The review highlights the need for improved injector characterization methods, more information of droplet transport characteristics in turbulent flow and continued development of more complete two-phase turbulent models.
The HEAO-B Gas Control System consists of a high pressure gas storage supply together with distribution and regulation assemblies and their associated electronics for management of gas required for HEAO-B X-ray counter experiments. The Gas Control System replenishes a gas mixture (82 percent argon, 12.3 percent carbon dioxide, 5.7 percent xenon) in the counter volumes which is lost by: diffusion through controlled leakage plugs, diffusion through counter windows, and consumption resulting from periodic purges. The gas density in each counter volume is maintained constant to within 0.25 percent by comparison with a sealed reference volume. The system is fully redundant, capable of operating at atmospheric pressure as well as in a vacuum, contains interlocks which shut down gas flow in the event of either leakage or excessive pressure, and is able to shut down counter high voltage if counter pressure is abnormally low. The system is electronically controlled by ground command and self-sustaining in orbit for a period of at least one year.