Engineering topics

Moynihan, P. I.

Publications and source records attributed to Moynihan, P. I..

26 records · Page 2

NASA NTRS1976

New potentials for conventional aircraft when powered by hydrogen-enriched gasoline

Hydrogen enrichment for aircraft piston engines is under study in a new NASA program. The objective of the program is to determine the feasibility of inflight injection of hydrogen in general aviation aircraft engines to reduce fuel consumption and to lower emission levels. A catalytic hydrogen generator will be incorporated as part of the air induction system of a Lycoming turbocharged engine and will generate hydrogen by breaking down small amounts of the aviation gasoline used in the normal propulsion system. This hydrogen will then be mixed with gasoline and compressed air from the turbocharger before entering the engine combustion chamber. The paper summarizes the results of a systems analysis study. Calculations assuming a Beech Duke aircraft indicate that fuel savings on the order of 20% are possible. An estimate of the potential for the utilization of hydrogen enrichment to control exhaust emissions indicates that it may be possible to meet the 1979 Federal emission standards.

Menard, W. A.↗

NASA NTRS1975

High-power CW laser using hydrogen-fluorine reaction

Continuous-wave laser has been proposed based on reaction of hydrogen and fluorine. Hydrogen is produced by dissociation of hydrazine, which can be stored as liquid in light containers at room temperature.

Moynihan, P. I.↗

NASA NTRS1973

Performance characterization tests of three 0.44-N (0.1 lbf) hydrazine catalytic thrusters

The 0.44-N (0.1-lbf) class of hydrazine catalytic thruster has been evaluated to assess its capability for spacecraft limit-cycle attitude control with thruster pulse durations on the order of 10 milliseconds. Dynamic-environment and limit-cycle simulation tests were performed on three commercially available thruster/valve assemblies, purchased from three different manufacturers. The results indicate that this class of thruster can sustain a launch environment and, when properly temperature-conditioned, can perform limit-cycle operations over the anticipated life span of a multi-year mission. The minimum operating temperature for very short pulse durations was determined for each thruster. Pulsing life tests were then conducted on each thruster under a thermally controlled condition which maintained the catalyst bed at both a nominal 93 C (200 F) and 205 C (400 F). These were the temperatures believed to be slightly below and very near the minimum recommended operating temperature, respectively. The ensuing life tests ranged from 100,000 to 250,000 pulses at these temperatures, as would be required for spacecraft limit-cycle attitude control applications.

Moynihan, P. I.↗

NASA NTRS1972

Attitude propulsion technology for TOPS

The thermoelectric outer planet spacecraft (TOPS) attitude propulsion subsystem (APS) effort is discussed. It includes the tradeoff rationale that went into the selection of an anhydrous hydrazine baseline system, followed by a discussion of the 0.22 N thruster and its integration into a portable, self-contained propulsion module that was designed, developed, and man rated to support the TOPS single-axis attitude control tests. The results of a cold-start feasibility demonstration with a modified thruster are presented. A description of three types of 0.44 thrusters that were procured for in-house evaluation is included along with the results of the test program. This is followed by a description of the APS feed system components, their evaluations, and a discussion of an evaluation of elastomeric material for valve seat seals. A list of new technology items which will be of value for application to future systems of this type is included.

Moynihan, P. I.↗

NASA NTRS1972

A portable hydrazine attitude propulsion test system

The portable hydrazine attitude propulsion module is described that was designed and developed to support the attitude control pitch axis simulation tests performed on an air bearing table for the thermoelectric outer planet spacecraft program. The propulsion module was a self-contained, liquid hydrazine propulsion system from which the exhausted gases were generated within the catalyst bed of either of two nominal 0.22-N opposing thrusters. The module, which was designed for convenient assembly onto and removal from an air bearing table, was tested to establish its operational safety. This test history and the very conservative design of the module enabled it to be man-rated for operation in the presence of personnel. The report briefly summarizes the system operations during air bearing table tests, presents a detailed description of the propulsion module hardware, and discussing the system evolution.

Moynihan, P. I.↗

NASA NTRS1972

Small rocket exhaust plume data

During recent cryodeposit tests with an 0.18-N thruster, the mass flux in the plume back field was measured for the first time for nitrogen, carbon dioxide, and a mixture of nitrogen, hydrogen, and ammonia at various inlet pressures. This mixture simulated gases that would be generated by a hydrazine plenum attitude propulsion system. The measurements furnish a base upon which to build a mathematical model of plume back flow that will be used in predicting the mass distribution in the boundary region of other plumes. The results are analyzed and compared with existing analytical predictions.

Chirivella, J. E.↗

NASA NTRS1972

Minimum impulse tests of 0.45-N liquid hydrazine catalytic thrusters

An exploratory test series was conducted on three types of 0.45-N (0.1 lbf) liquid hydrazine thrusters to ascertain the minimum impulse bit capability for this class of engine. The test series is described and the results are presented. The testing was performed at 21 and 145 C (70 and 300 F) while maintaining nominal 0.45 N (0.1 lbf) upstream conditions. Valve on-times as low as 0.008 sec were applied. Impulse bits were observed for thruster temperatures of 21 and 145 C (70 and 300 F), respectively.

Moynihan, P. I.↗

NASA NTRS1971

TOPS attitude propulsion subsystem technology

The thermoelectric outer-planet spacecraft (TOPS) attitude propulsion subsystem effort is summarized. It includes the tradeoff rationale that went into the selection of anhydrous hydrazine as the propellant, and a brief description of three types of 0.445-N (100-mlbf) thrusters that were purchased for in-house evaluation. A discussion is also included of the 0.2224-N (50-mlbf)-developed thrusters and their integration with a portable, completely enclosed, propulsion module that was designed and developed to support the TOPS single-axis attitude control tests in the celestarium.

Moynihan, P. I.↗