Engineering topics

Jones, J. J.

Publications and source records attributed to Jones, J. J..

32 records · Page 2

NASA NTRS1976

An investigation of the effects of mass loss, shape change and real gas aerodynamics on a Jovian atmospheric reconstruction experiment

A survey of the effects of mass loss, shape change and real-gas aerodynamics on a Jovian atmospheric reconstruction experiment is carried out. Techniques used to reconstruct atmospheric profiles from entry probe measurements are discussed and some of the parameters which affect their accuracy are identified. Trajectory analyses and real-gas, radiatively-coupled flow field analyses (which include the effects of mass loss and shape change) are carried out for several candidate probe configurations. From these analyses, uncertainties in the atmospheric reconstruction procedure are estimated. Finally, the prospects for reducing these uncertainties by optimizing probe configuration and by instrumentation of the probe heat shield to measure actual shape change are considered.

Walberg, G. D.↗

NASA NTRS1976

Effect of probe configuration on radiative heating during Jovian entry

The radiative heating to the probe's surface and the effects of the recession of the heat shield caused by this heating are analyzed for five initial probe configurations for a Jovian entry. The initial configurations are spherically capped, conical bodies and hyperboloids. The results show that severe blunting of the nose region occurs for all configurations due to ablation of the heat shield caused by the large radiative heating rates. Recession at the nose region can possibly cause a concavity at the stagnation point. Furthermore, the recession of the heat shield, especially for the spherically capped, conical bodies, will be underpredicted if the change in the probe's shape during the entry is neglected in an analysis.

Sutton, K.↗

NASA NTRS1975

Incident shock-wave characteristics in air, argon, carbon dioxide, and helium in a shock tube with unheated helium driver

Incident shock-wave velocities were measured in the Langley 6-inch expansion tube, operated as a shock tube, with air, argon, carbon dioxide, and helium as test gases. Unheated helium was used as the driver gas and most data were obtained at pressures of approximately 34 and 54 MN/sq m. A range of pressure ratio across the diaphragm was obtained by varying the quiescent test-gas pressure, for a given driver pressure, from 0.0276 to 34.5 kN/sq m. Single- and double-diaphragm modes of operation were employed and diaphragms of various materials tested. Shock velocity was determined from microwave interferometer measurements, response of pressure transducers positioned along interferometer measurements, response of pressure transducers positioned along the driven section (time-of-arrival gages), and to a lesser extent, measured tube-wall pressure. Velocities obtained from these methods are compared and limitations of the methods discussed. The present results are compared with theory and the effects of diaphragm mode (single or double diaphragm), diaphragm material, heating of the driver gas upon pressurization of the driver section, diaphragm opening time, interface mixing, and two-dimensional (nonplanar) flow are discussed.

Miller, C. G., III↗

NASA NTRS1975

Langley Research Center entry aerothermodynamic technology development in support of Pioneer Venus multiprobe mission studies

A program of entry aerothermodynamics has been conducted to support the Pioneer Venus multiprobe mission. Aspects of the study include radiative property data, radiative blockage effectiveness measurements, heating calculations, aerodynamic and convective heating studies, and radio communications blackout models. Some of the historical background for the investigation is reviewed, and recommendations are made concerning the use of the developed technology in probe design and the continuation of certain elements of the program.

Olstad, W. B.↗

NASA NTRS1975

Magnetic mass spectrometer search at 2750 m. for hypothetical massive particles

A search was conducted for hypothetical singly charged massive particles which might be produced in collisions of very highly energetic cosmic ray particles with nuclei in the upper atmosphere. If such particles have sufficiently long lifetime and small cross section for interaction, they could survive to mountain altitude. A cosmic ray spectrometer consisting of superconducting magnet, wire spark chambers and time-of-flight scintillation counters was used to search for these particles at mountain altitude (2750 m). For any choice of hypothetical mass in the 5 to 10 GeV/c-squared range the upper limit to the vertical intensity of the particle was observed to be less than or roughly equal to 10 to the -6th/sq. cm/s/(GeV/c).

Barber, H. B.↗

NASA NTRS1975

Cosmic ray mass and momentum spectra at mountain altitude

A cosmic ray mass spectrometer using a superconducting magnet, digitized wire spark chambers, and a scintillation counter time of flight system, has been operated at an altitude of 2750 meters. The apparatus is most sensitive to charged particles with momentum to mass ratios between 0.2 and 2.0. Results for the momentum spectra of protons and deuterons are presented, as well as upper limits for H-3 and He-3. The reaction nucleon + nucleon yields deuteron + pion accounts for part of the observed deuteron spectrum in the 0.9 to 3 GeV/c region.-

Barber, H. B.↗

NASA NTRS1975

Performance of and planned improvements to a mountain altitude cosmic ray mass spectrometer

A cosmic ray mass spectrometer with superconducting magnet, wire spark chambers, and time-of-flight scintillation counters has been operated at an altitude of 2750 meters. Various specifications of the spectrometer are presented and the method of event analysis described. Corrections to the data, resolutions and efficiencies of the spark chambers, and momentum resolution are discussed. Recent and planned improvements of the apparatus are indicated.

Jones, J. J.↗

NASA NTRS1974

Recommended radiative property data for Venusian entry calculations

A compilation of experimental and calculated data on the radiative properties species important in Venusian entry is presented. Molecular band systems, atomic lines, free-bound, and free-free continua are considered for the principal radiating species of shock heated carbon dioxide. A limited amount of data pertinent to the species in the ablation layer is also included. The assumption is made that the Venus atmosphere so closely approximates pure CO2 that the inviscid layer radiation is due almost entirely to thermally excited CO2. The only exception is the inclusion of data on the Violet band system of CN. Recommendations are made as to best property values for radiative heating calculations. A review of the basic equations and the relationships of the various emission-absorption gas porperties is also included.

Jones, J. J.↗

NASA NTRS1974

Radiative property data for Venusian entry: A compendium

A compilation of experimental and calculated data on the radiative properties of species important in Venusian entry is presented. Molecular band systems, atomic lines, free-bound continua, and free-free continua are considered for the principal radiating species of shock-heated carbon dioxide. Data pertinent to the species in the ablation layer are included. The Venus atmosphere so closely approximates pure carbon dioxide (CO2) that the inviscid layer radiation is due almost entirely to thermally excited CO2. Data are included on the violet band system of the cyanogen radical CN. Recommendations are made as to best property values for radiative heating calculations. A review of the basic equations and the relationships of the various emission-absorption gas properties is included.

Jones, J. J.↗

NASA NTRS1966