Engineering topics

Moser, M. D.

Publications and source records attributed to Moser, M. D..

7 records

NASA NTRS1996

Combustion Zone Characterization of GO2/GH2 Rocket Using Laser-Induced Fluorescence of OH

A series of studies were undertaken to measure various parameters such as velocity, species concentration, and temperature downstream of a shear coaxial injector in an optically accessible uni-element rocket chamber. Techniques applied include: laser Doppler velocimetry (LDV) for velocity; laser light scattering (LLS) for flow visualization and estimating mixture fraction and density; laser induced fluorescence (LIF) of hydroxyl radials (OH) to determine the characteristics and extent of the reaction zone; and Raman spectroscopy to measure major species concentration and temperature.

Moser, M. D.↗

NASA NTRS1994

Density and mixture fraction measurements in a GO2/GH2 uni-element rocket chamber

In recent years, there has been a renewed interest in gas/gas injectors for rocket combustion. Specifically, the proposed new concept of full-flow oxygen rich preburner systems calls for the injection of both oxygen and hydrogen into the main chamber as gaseous propellants. The technology base for gas/gas injection must mature before actual booster class systems can be designed and fabricated. Since the data base for gas/gas injection is limited to studies focusing on the global parameters of small reaction engines, there is a critical need for experiment programs that emphasize studying the mixing and combustion characteristics of GO2 and GH2 propellants from a uni-element injector point of view. The experimental study of the combusting GO2/GH2 propellant combination in a uni-element rocket chamber also provides a simplified environment, in terms of both geometry and chemistry, that can be used to verify and validate computational fluid dynamic (CFD) models.

Moser, M. D.↗

NASA NTRS1993

An experimental study of characteristic combustion-driven flows for CFD validation

The application of laser-based diagnostic techniques has become commonplace to a wide variety of combustion problems. New insights into combustion phenomena at a level previously unattainable has been made possible by non-intrusive measurements of velocity, temperature, and species. However, due to the adverse conditions which exist inside rocket engines, relatively few studies have addressed these combustion environments. The high pressure, high speed, combusting environment in a rocket engine prohibits the application of several measurement techniques. However, in the rocket community, there is a critical need for rocket flow field data to validate computational fluid dynamic (CFD) codes. Currently at Penn State, there is an effort to obtain flowfield measurements inside a rocket engine. Velocity measurements have been made inside the combustion chamber of a uni-element (shear coaxial injector) optically accessible rocket chamber at several axial locations downstream of the injector. These measurements, combined with future measurements, will provide benchmark data for CFD code validation.

Pal, S.↗

NASA NTRS1993

Flowfield Characterization in a LOX/GH2 Propellant Rocket

The objective of the current work is to experimentally characterize the flowfield associated with an uni-element shear coaxial injector burning liquid oxygen/gaseous hydrogen (LOX/GH2) propellants. These experiments were carried out in an optically-accessible rocket chamber operating at a high pressure (approximately 400 psia). Quantitative measurements of drop size and velocity were obtained along with qualitative measurements of the disintegrating jet.

Pal, S.↗

NASA NTRS1993

Flowfield characteristics in a liquid propellant rocket

Measurements of LOX drop size and velocity in a uni-element liquid propellant rocket chamber are presented. The use of the Phase Doppler Particle Analyzer in obtaining temporally averaged probability density functions of drop size in a harsh rocket environment has been demonstrated. Complementary measurements of drop size/velocity for simulants under cold flow conditions are also presented. The drop size/velocity measurements made for combusting and cold flow conditions are compared, and the results indicate that there are significant differences in the two flowfields.

Pal, S.↗

NASA NTRS1993

OH-radical imaging and velocity field measurements in a gaseous hydrogen/oxygen rocket

Detailed measurements of the OH-radical and velocity fields for a shear coaxial unielement rocket chamber burning gaseous hydrogen and gaseous oxygen propellants are reported. The velocity measurements indicate that a highly unsteady flowfield results from the turbulent combustion of the coaxial jets. The core of the oxygen stream is observed to remain intact well downstream of the injector face while the maximum turbulent intensities in the shear layer region between the hydrogen and oxygen flows were measured to be about 25 percent. Both 1D and 2D laser-induced fluorescence studies of the OH-radical are reported and provide information on the evolving flame structure under rocketlike conditions. Both single and multiple laser pulse images indicate that the structure of the unsteady flowfield is directly reflected in the combustion zone flame structure. Preliminary results regarding analysis approaches and interpretation of the data are also presented.

Moser, M. D.↗

NASA NTRS1992

Shear coaxial injector atomization phenomena for combusting and non-combusting conditions

Measurements of LOX drop size and velocity in a uni-element liquid propellant rocket chamber are presented. The use of the Phase Doppler Particle Analyzer in obtaining temporally-averaged probability density functions of drop size in a harsh rocket environment has been demonstrated. Complementary measurements of drop size/velocity for simulants under cold flow conditions are also presented. The drop size/velocity measurements made for combusting and cold flow conditions are compared, and the results indicate that there are significant differences in the two flowfields.

Pal, S.↗