Unielement Oxygen Rich Preburner

A full-flow, staged combustion cycle using an oxygen-rich preburner has been a candidate for use on the proposed reusable launch vehicle. The oxygen-rich combustion gas used to drive the turbine system would have a high density consequently, the required turbine power can be obtained by the low-temperature preburner products. This will improve turbopump operability and durability. However, before full-scale engine development can proceed, the issues of ignition characteristics, flame stability,...

Magnetic Damping Test of Convective Flows in Microgravity

The fundamental objectives of this experiment are (1) to test experimentally the validity of modeling predictions applicable to convective-flow magnetic damping in conductive melts as this applies to the directional solidification of metallic and semiconductor materials in the reduced-gravity levels available in low-Earth orbit and (2) to assess the effectiveness of magnetic fields in reducing the fluid-flow occurrence in these materials during the space processing that results from density...

Eric M EarhartED

The interactions and phase relations between a rotor's elastic and inertial forces can lead to subsynchronous whirl, a type of self-excited vibration at frequencies near the lowest critical frequency of the rotor. This potentially destructive phenomenon imposes limits on turbomachinery performance. As an example, subsynchronous whirl caused serious development problems on the space shuttle main engine's high-pressure fuel turbopump. Early in the development program, the speed of the turbopump...

George MyersED

The objective for this 18-month effort is to provide current and complete upgrade for the TREETOPS suite of analysis tools. This upgrade will provide the required format for maintaining the current tools as well as accommodations for future enhancements. TREETOPS is a time-history simulation of the motion of a complex multibody flexible structure in a tree topology with active control elements. TREETOPS refers to the simulation program, TREETOPS, plus two interactive preprocessors, TREESET and...

Katherine K MimsED

A ceramic composite integrally bladed turbine disk (blisk) combines two important technology benefits (1) reduced weight resulting from both a reduced parts count and from use of a lower-density material and (2) improved damping, a derivative of the inherent damping offered by continuous fiber-reinforced ceramic composites. An added benefit is the possibility of reduced operating costs due to enhanced durability (relative to metals) in the intended gaseous oxygen-rich environment. However, the...

Technology

Typically, turbomachinery used in liquid rocket engines is composed of complex geometries made from high strength-to-weight super alloys. These high-performance machines usually have long design and fabrication cycle times on the order of 3 to 5 years. Such factors increase development time and result in high costs. A simple, low-cost turbopump was designed in-house to demonstrate the ability to reduce the overall cost and life-cycle time of turbomachinery. The subject turbopump design,...

Solar Thermal Propulsion

Solar thermal propulsion is an advanced propulsion concept that utilizes concentrated solar energy to heat a propellant and thereby produce thrust. This propulsion concept will be used on an upper-stage vehicle with the main application being the transfer of payloads from low-Earth orbit to geostationary Earth orbit. The solar thermal propulsion concept is characterized as having low thrust (2 to 5 pounds force), high specific impulse (800 to 1,000 seconds), and is a much more efficient means...

Tom E NesmanED

Cavitation is the process of boiling fluid that occurs when local fluid dynamic pressures in the areas of accelerated flow drop below the vapor pressure of the fluid. When cavitation occurs within the turbopumps of liquid rocket engine propulsion systems, it can severely degrade overall system performance, cause excessive structural vibration, and damage turbopump blades. The Coherent-Phase Cavitation-Monitoring System will utilize an innovative coherent-phase wide-band demodulation technique...

Integral Leak Before Burst

Constant s0 Material's yield strength (pounds per square inch) e0 Corresponding strain to sd c Uncracked ligament length (inches) Institute elastic-plastic fracture mechanics expression (function of material and geometry) a Actual crack size or depth (inches) exponent P Applied load either tensile (pound mass force) or moment (inches per pound mass force) P0 Characterizing yield load (pound mass force or inches per pound mass force). The estimation of the J-integral for a particular problem now...

Hybrid Rocket Cold Flow Modeling

Due to recent renewed interest in hybrid rocket motors, MSFC has participated in several hot-fire hybrid test programs. A major concern in several of these tests has been low-frequency pressure oscillations within the motor combustion chamber. The Propulsion Laboratory's Motor Systems Division, in conjunction with Auburn University's Dr. Rhonald Jenkins, submitted a Center Director's Discretionary Fund proposal to investigate such oscillations approved September 1995 . Through ongoing research...

Prediction of Nonlinear Optical Properties of Organic Materials

To allow screening of potential nonlinear optical organic compounds, researchers have developed a procedure to predict second- and third-order polarizabilities of organic materials that, within families of compounds, is accurate within 25 percent of the experimental values. This will facilitate nonlinear optical research by limited synthesis of new compounds to those most likely to exhibit appropriate properties. The procedure is as follows a Using a semi-empirical Hamiltonian AM1 , the...

Tripropellant Injector and Combustion Technology

Gaseous Combustion Coaxial Inyector

A tripropellant engine provides an opportunity to burn hydrocarbon fuel with oxygen efficiently during the boost phase and hydrogen with oxygen afterwards. This concept offers possible advantages for application in a reusable launch vehicle for reasons of weight and cost savings, since only one engine needs to be developed. To advance the state of the art with respect to the development of injection elements, Pennsylvania State University has designed two types for testing. The first one, a...

Mag Lifter

Achieving an affordable and reliable launch infrastructure for low-cost, routine access to space is one of the enduring challenges of the space age. In a marketplace dominated by expendable launch vehicles grounded in the technology base of the 1950's and 1960's, diverse innovative approaches have been conceived since 1970 for reducing the cost per pound for transport to low-Earth orbit. For example, the space shuttle a largely reusable vehicle was developed in the 1970's with the goal of...

The Dusty Plasma Experiment

Much the same way dust collects on computer monitors so too does dust respond in space. The electrical forces resulting from a charge on a grain of dust will often be stronger than its gravitational force weight and will frequently dominate the interaction within a cloud of dust grains. In a space environment, charged electrons and ions interact with dust grains, resulting in the formation of what is called a dusty plasma. Dusty plasmas are found in most regions of space. Because of this,...

Magnetically Actuated Propellant Orientation

In a low-gravity environment, acquisition of vapor-free propellant is complicated by the indeterminate location of bulk liquid with respect to the tank outlet. Proper design of engine feed or propellant transfer systems requires methods to control liquid orientation and an understanding of fluid motion in response to disturbances and imposed accelerations. Traditional approaches for controlling and positioning cryogenic liquids, such as periodic thruster firings and capillary retention devices,...

Main and Preburner Injector Technology

MSFC is currently conducting combustion research of injector elements using small windowed combustors. The objectives of this testing which will be accomplished with a combination of advanced laser diagnostics and traditional engineering measurements are to provide data that can be used to design liquid-propellant rocket injectors for optimum operation with respect to performance, heat transfer, combustion stability, and materials compatibility. The foundation of the laser measurements will be...

Pressure Oscillations in Hybrid Rocket Motors

Beginning in 1992, a joint government-industry program has been conducted at MSFC to develop hybrid rocket motors. Hybrid rocket motors combine an inert solid fuel grain with a gaseous or liquid oxidizer in an effort to realize the benefits of both liquid and solid rocket motors. This joint effort, funded by both private and public moneys, is known as the Joint Independent Research and Development Hybrid Program. One of the most significant findings to date has been the recurrence of...