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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

A comparative study of the effects of inhibitor stub length on solid rocket motor combustion chamber pressure oscillations: RSRM at T = 80 seconds, preliminary results

Results from a continuing, time-accurate computational study of the combustion gas flow inside the Space Shuttle Redesigned Solid Rocket Motor (RSRM) are presented. These computational fluid dynamic (CFD) analyses duplicate unsteady flow effects which interact in the RSRM to produce pressure oscillations, and resulting thrust oscillations, at nominally 15, 30, and 45 Hz. Results of the Navier-Stokes computations made at mean pressure and flow conditions corresponding to 80 seconds after motor ignition both with and without a protruding, rigid inhibitor at the forward joint cavity are presented here.

Chasman, D.↗
NASA NTRS2000

Flow Simulation of Solid Rocket Motors: Sub-Scale Air Flow Simulation of Port Flows - 2

The injection-flow issuing from a porous medium in the cold-flow simulation of internal port flows in solid rocket motors is characterized by a spatial instability termed pseudoturbulence that produces a rather non-uniform (lumpy) injection-velocity profile. The objective of this study is to investigate the interaction between the injection- and the developing axial-flows. The findings show that this interaction generally weakens the lumpy injection profile and affects the subsequent development of the axial flow. The injection profile is found to depend on the material characteristics, and the ensuing pseudoturbulence is a function of the injection velocity, the axial position and the distance from the porous wall. The flow transition (from laminar to turbulent) of the axial-flow is accelerated in flows emerging from smaller pores primarily due to the higher pseudoturbulence produced by the smaller pores in comparison to that associated with larger pores. In flows with rather uniform injection-flow profiles (weak or no pseudoturbulence), the axial and transverse velocity components in the porous duct are found to satisfy the sine/cosine analytical solutions derived from inviscid assumptions. The transition results from the present study are compared with previous results from surveyed literature, and detailed flow development measurements are presented in terms of the blowing fraction, and characterizing Reynolds numbers.

Yeh, Y. P.↗
NASA NTRS1981

Shuttle solid rocket motor nozzle alternate ablative evaluation

A series of subscale tests are shown to suggest that a lower-cost ablative material than the rayon-based carbon ablative currently used in the Space Shuttle Solid Rocket Motor (SRM) may be used as a substitute. Six such ablatives with outstanding performance characteristics, using spun PAN and continuous pitch and PAN fibers instead of the present, continuous rayon, were identified in the course of tests with HTPB/AL/AP solid propellant grains with a burn time of 12 sec. The test nozzle features an initial throat diameter of 2.2 in. and a 6.1 expansion ratio. In addition to nozzle structural feature drawings, extensive test data tables and propellant formulation and properties tables are provided.

Powers, L. B.↗
NASA NTRS1987

Structural analysis of a bolted joint concept for the Space Shuttle's solid rocket motor casing

The Space Shuttle Challenger accident is thought to have been caused by the failure of one of the tang-clevis joints which join together the casing segments of the Solid Rocket Motors (SRM). Excessive displacement between the tang and clevis, possibly unseating the O-ring seals, may have initiated the resulting accident. An effort was undertaken at NASA's Langley Research Center to design an alternative concept for mating the casing segments. A bolted flanged joint concept was designed and analyzed to determine if the concept would effectively maintain a seal while minimizing joint weight and controlling stress levels. It is shown that under the loading condition analyzed the seal area of the joint remains seated. The only potential stress problem is a stress concentration in the flange at the edge of the bolt hole, which is highly localized. While heavier than the existing joint, this concept does have some advantages which make the bolted joint an attractive alternative.

Lindell, Michael C.↗
NASA NTRS1992

Current status of the development of an ignition transient model for solid rocket motors

The primary objectives of the computational fluid dynamics (CFD) code are to calculate the pressure rise rate and the maximum chamber pressure which occurs during the first second of the Advanced Solid Rocket Motor (ASRM) action time. A specific objective is to determine the relative difference between the ignition transients produced during a single port igniter and that produced by a multiport igniter. Discussed here are the results obtained from the one dimensional code and the plans for the development of the three dimensional code. Much of the information is given in viewgraph form.

Luke, Gary D.↗
NASA NTRS1995

Analysis of advanced solid rocket motor ignition phenomena

This report presents the results obtained from an experimental analysis of the flow field in the slots of the star grain section in the head-end of the advanced solid rocket motor during the ignition transient. This work represents an extension of the previous tests and analysis to include the effects of using a center port in conjunction with multiple canted igniter ports. The flow field measurements include oil smear data on the star slot walls, pressure and heat transfer coefficient measurements on the star slot walls and velocity measurements in the star slot.

Foster, Winfred A., Jr.↗
NASA NTRS2000

Thermal-Flow Code for Modeling Gas Dynamics and Heat Transfer in Space Shuttle Solid Rocket Motor Joints

A new, thermal-flow simulation code, called SFLOW. has been developed to model the gas dynamics, heat transfer, as well as O-ring and flow path erosion inside the space shuttle solid rocket motor joints by combining SINDA/Glo, a commercial thermal analyzer. and SHARPO, a general-purpose CFD code developed at Thiokol Propulsion. SHARP was modified so that friction, heat transfer, mass addition, as well as minor losses in one-dimensional flow can be taken into account. The pressure, temperature and velocity of the combustion gas in the leak paths are calculated in SHARP by solving the time-dependent Navier-Stokes equations while the heat conduction in the solid is modeled by SINDA/G. The two codes are coupled by the heat flux at the solid-gas interface. A few test cases are presented and the results from SFLOW agree very well with the exact solutions or experimental data. These cases include Fanno flow where friction is important, Rayleigh flow where heat transfer between gas and solid is important, flow with mass addition due to the erosion of the solid wall, a transient volume venting process, as well as some transient one-dimensional flows with analytical solutions. In addition, SFLOW is applied to model the RSRM nozzle joint 4 subscale hot-flow tests and the predicted pressures, temperatures (both gas and solid), and O-ring erosions agree well with the experimental data. It was also found that the heat transfer between gas and solid has a major effect on the pressures and temperatures of the fill bottles in the RSRM nozzle joint 4 configuration No. 8 test.

Wang, Qunzhen↗
NASA NTRS1972

Solid rocket motors for the Space Shuttle booster.

The evolution of the space shuttle booster system is reviewed from its initial concepts based on liquid-propellant reusable boosters to the final selection of recoverable, solid-fuel rocket motors. The rationale associated with each of the several major decisions in the evolution process is discussed. It is shown that the external tank orbiter configuration emerging from the latest studies takes maximum advantage of the solid rocket motor development experience and promises to be the optimum configuration for fulfilling the paramount shuttle program requirements of minimum total development risk within acceptable costs.

Odom, J. B.↗
NASA NTRS1978

X-ray fluorescence analysis for prediction of Space Shuttle solid rocket motor performance

Analysis of uncured solid propellant by X-ray fluorescence has been conducted on mixes prepared for four development motors produced for the Space Shuttle SRM Project. X-ray readings for chlorine (ammonium perchlorate) and iron (ferric oxide) were recorded for each mix during processing of the propellant. These values were used to predict burning rates for uncured acceptance, uncured acoustic emission and cured acoustic emission strands. Predicted burning rates all fell within control limits and when compared to actual burning rates, most were within experimental error. The X-ray analysis required one-third the time of current methods and met casting schedules.

Pulsipher, H. G.↗
NASA NTRS2001

Reusable Solid Rocket Motor Nozzle Joint-4 Thermal Analysis

This study provides for development and test verification of a thermal model used for prediction of joint heating environments, structural temperatures and seal erosions in the Space Shuttle Reusable Solid Rocket Motor (RSRM) Nozzle Joint-4. The heating environments are a result of rapid pressurization of the joint free volume assuming a leak path has occurred in the filler material used for assembly gap close out. Combustion gases flow along the leak path from nozzle environment to joint O-ring gland resulting in local heating to the metal housing and erosion of seal materials. Analysis of this condition was based on usage of the NASA Joint Pressurization Routine (JPR) for environment determination and the Systems Improved Numerical Differencing Analyzer (SINDA) for structural temperature prediction. Model generated temperatures, pressures and seal erosions are compared to hot fire test data for several different leak path situations. Investigated in the hot fire test program were nozzle joint-4 O-ring erosion sensitivities to leak path width in both open and confined joint geometries. Model predictions were in generally good agreement with the test data for the confined leak path cases. Worst case flight predictions are provided using the test-calibrated model. Analysis issues are discussed based on model calibration procedures.

Clayton, J. Louie↗
NASA NTRS2002

Thermal Analysis of a Carbon Fiber Rope Barrier for Use in the Reusable Solid Rocket Motor Nozzle Joint-2

This study provides development and verification of analysis methods used to assess performance of a carbon fiber rope (CFR) thermal barrier system that is currently being qualified for use in Reusable Solid Rocket Motor (RSRM) nozzle joint-2. Modeled geometry for flow calculations considers the joint to be vented with the porous CFR barriers placed in the 'open' assembly gap. Model development is based on a 1-D volume filling approach where flow resistances (assembly gap and CFRs) are defined by serially connected internal flow and the porous media 'Darcy' relationships. Combustion gas flow rates are computed using the volume filling code by assuming a lumped distribution total joint fill volume on a per linear circumferential inch basis. Gas compressibility, friction and heat transfer are included in the modeling. Gas-to-wall heat transfer is simulated by concurrent solution of the compressible flow equations and a large thermal 2-D finite element (FE) conduction grid. The derived numerical technique loosely couples the FE conduction matrix with the compressible gas flow equations. Free constants that appear in the governing equations are calibrated by parametric model comparison to hot fire subscale test results. The calibrated model is then used to make full-scale motor predictions using RSRM aft dome environments. Model results indicate that CFR thermal barrier systems will provide a thermally benign and controlled pressurization environment for the RSRM nozzle joint-2 primary seal activation.

Clayton, J. Louie↗
NASA NTRS2001

Thermal Analysis of a Carbon Fiber Rope Barrier for Use in the Reusable Solid Rocket Motor Nozzle Joint-2

This study provides for development and verification of analysis methods used to assess performance of a carbon fiber rope (CFR) thermal barrier system that is currently being qualified for use in Reusable Solid Rocket Motor (RSRM) nozzle joint-2. Modeled geometry for flow calculations considers the joint to be vented with the porous CFR barriers placed in the "open' assembly gap. Model development is based on a 1-D volume filling approach where flow resistances (assembly gap and CFRs) are defined by serially connected internal flow and the porous media "Darcy" relationships. Combustion gas flow rates are computed using the volume filling code by assuming a lumped distribution total joint fill volume on a per linear circumferential inch basis. Gas compressibility, friction and heat transfer are included in the modeling. Gas-to-wall heat transfer is simulated by concurrent solution of the compressible flow equations and a large thermal 2-D finite element (FE) conduction grid. The derived numerical technique loosely couples the FE conduction matrix with the compressible gas flow equations, Free constants that appear in the governing equations are calibrated by parametric model comparison to hot fire subscale test results. The calibrated model is then used to make full-scale motor predictions using RSRM aft dome environments. Model results indicate that CFR thermal barrier systems will provide a thermally benign and controlled pressurization environment for the RSRM nozzle joint-2 primary seal activation.

Clayton, J. Louie↗
NASA NTRS2000

NARC Rayon Replacement Program for the Space Shuttle Reusable Solid Rocket Motor Nozzle: Screening Summary

Thiokol Corporation and NASA MSFC are jointly developing a replacement for North American Rayon Corporation (NARC) Aerospace Grade Rayon (1650/720 continuous filament), the precursor for the Carbon Cloth Phenolic (CCP) ablatives used in the Space Shuttle Reusable Solid Rocket Motor (RSRM) Nozzles. NARC discontinued production of Aerospace Grade Rayon in September 1997. NASA maintains a stockpile of NARC Rayon to support RSRM production through the summer of 2005. The program plan for selection and qualification of a replacement for NARC rayon was approved in August 1998. Screening activities began in February 1999. The intent of this paper is to provide a summary of the data generated during the screening phase of the NARC Rayon Replacement Program. Twelve cellulose based fibers (rayon and lyocell) were evaluated. These fibers were supplied by three independent vendors. Many of these fibers were carbonized by two independent carbonizers. Each candidate was tested according to standard acceptance test methods at each step of the manufacturing process. Additional testing was performed with the candidate CCPS, including hot fire tests, Process studies and mechanical and thermal characterization. Six of the twelve fiber candidates tested were dropped at the conclusion of Phase 1. The reasons for the elimination of these candidates included; difficulties in processing the material in the whitegoods, carbon and CCP forms; poor composite mechanical performance; and future availability concerns. The remaining six fibers demonstrated enough promise to merit continued evaluation and optimization of the CCP fabrication process. Note: Certain CCP data falls under the restrictions of US export laws, (ITAR, etc.) and will not be included in this paper.

Cook, R. V.↗
NASA NTRS1989

Accuracy analysis of the space shuttle solid rocket motor profile measuring device

The Profile Measuring Device (PMD) was developed at the George C. Marshall Space Flight Center following the loss of the Space Shuttle Challenger. It is a rotating gauge used to measure the absolute diameters of mating features of redesigned Solid Rocket Motor field joints. Diameter tolerance of these features are typically + or - 0.005 inches and it is required that the PMD absolute measurement uncertainty be within this tolerance. In this analysis, the absolute accuracy of these measurements were found to be + or - 0.00375 inches, worst case, with a potential accuracy of + or - 0.0021 inches achievable by improved temperature control.

Estler, W. Tyler↗
NASA NTRS1971

A systems approach of the nondestructive evaluation techniques applied to Scout solid rocket motors.

Review and appraisal of the status of the nondestructive tests applied to Scout solid-propellant rocket motors, using analytical techniques to evaluate radiography for detecting internal discontinuities such as voids and unbonds. Information relating to selecting, performing, controlling, and evaluating the results of NDE tests was reduced to a common simplified format. With these data and the results of the analytical studies performed, it was possible to make the basic appraisals of the ability of a test to meet all pertinent acceptance criteria and, where necessary, provide suggestions to improve the situation.

Oaks, A. E.↗
NASA NTRS1988

Space Shuttle solid rocket motor testing for return to flight - Transient Pressure Test Article test program

The Transient Pressure Test Article (TPTA) test program, which is being conducted at a new facility at NASA-Marshall, is described. The facility is designed to test and verify the sealing capability of the redesigned solid rocket motor's (RSRM) field, igniter, and nozzle joints. The test article consists of full-scale RSRM hardware loaded with inert propellant and assembled in a short stack configuration. The test facility is described as well as test implementation, test effectiveness, and test results.

Vibbart, Charles M.↗