LUNAR SOIL SIMULANT STUDY PHASE B, PART II-THERMAL CONDUCTIVITY

A STUDY WAS CONDUCTED TO DEVELOP A LUNAR SOIL SIMULANT WHOSE PHYSICAL BEHAVIOR IN THE EARTH'S GRAVITY FIELD APPROACHES THE ASSUMED BEHAVIOR OF A LUNAR SOIL IN THE REDUCED GRAVITY FIELD OF THE MOON. THE LUNAR SIMULANT WAS DERIVED FROM UNWEATHERED DIABASE ROCK CRUSHED AND PROCESSED SO AS TO FALL WITHIN A SPECIFIED GRADATION BAND. THE THERMAL CONDUCTIVITY WAS MEASURED IN AN APPARATUS CONSISTING OF COAXIAL ALUMINUM CYLINDERS. HEAT WAS INTRODUCED FROM A ROD HEATER, PLACED INSIDE THE INNER CYLINDER, AND WAS DISSIPATED THROUGH THE AIRCOOLED OUTER CYLINDER. TEMPERATURE MEASUREMENTS AT TWO DIFFERENT RADII DETERMINED THE RADIAL TEMPERATURE GRADIENT. THERMAL MEASUREMENTS WERE COMPLETED IN VACUUM OVER THE TEMPERATURE RANGE OF 200 K TO 425 K. FOUR DISTINCT COMBINATIONS OF THE SIZE FRACTIONS OF THIS MATERIAL PERMITTED EVALUATION OF GRAIN SIZE ON THE MEASUREMENT OF THERMAL CONDUCTIVITY WITHIN THE SAMPLE CONTAINER. THE RESULTS WERE INCONSISTENT FOR THE SAMPLES CONTAINING SIGNIFICANT QUANTITIES OF LARGE GRAINS, INDICATING THAT THE EXPERIMENTAL APPARATUS WAS NOT SUITABLE FOR MEASUREMENTS ON SAMPLES CONTAINING LARGE PARTICLES. EXPERIMENTAL RESULTS FOR THE LUNAR SOIL SIMULANT DEMONSTRATE THE STRONG DEPENDENCE OF THE EFFECTIVE ENVIRONMENT. THE RADIATIVE CONTRIBUTION TO THE EFFECTIVE THERMAL CONDUCTIVITY CONTINUES A TREND, REPORTED BY OTHERS OF AN INCREASE, IN THERMAL CONDUCTIVITY AS THE PARTICLE SIZE INCREASES. THE SOLID CONDUCTION DOES NOT FOLLOW THE TREND OF DECREASING CONDUCTIVITY WITH INCREASING PARTICLE SIZE. THE CONTRIBUTION APPEARS TO BE STRONGLY INFLUENCED BY THE GREATER NUMBER OF CONTACT POINTS AS DEVELOPED WITHIN A MATERIAL POSSESSING A WIDE RANGE OF PARTICLE SIZES.

• Supplemental Notes:
  • Tech Rept 4-83, 56 PP, 11 FIG, 8 TAB, PHOTS, 9 REF, 2 APP
• Authors:
  • Hubbard, J H
  • Gall, E S
  • Kahn, H S
• Publication Date: 0

Media Info

• Serial:
  • Ohio River Division Laboratories Technical Rpt

Subject/Index Terms

• TRT Terms: Environmental impacts; Grain size (Geology); Gravity; Measurement; Moon; Simulation; Soils; Temperature gradients; Temperature measurement; Thermal conductivity
• Uncontrolled Terms: Lunar soils; Particle size distribution
• Subject Areas: Environment; Geotechnology; Highways;

Filing Info

• Accession Number: 00229869
• Record Type: Publication
• Files: TRIS
• Created Date: Oct 5 1970 12:00AM