Apparatus for determining thermophysical properties of test specimens

Abstract

Abstract Apparatus for directly measuring the quantity √ρck of a test specimen such as a wind tunnel model where ρ is the density, c is the specific heat and k is the thermal conductivity of the specimen. The test specimen and a reference specimen are simultaneously subjected to the heat from a heat source. A thermocouple is attached to the reference specimen for producing a first electrical analog signal proportional to the heat rate Q that the test specimen is subjected to and an infrared radiometer that is aimed at the test specimen produces a second electrical analog signal proportional to the surface temperature T of the test specimen. An analog-to-digital converter converts the first and second electrical analog signals to digital signals. These digital signals are applied to a computer for determining the quantity √ρck by computing the quantity ##EQU1## WHERE T i is the initial test specimen temperature and t is the elapsed time from the time that the specimens were first subjected to the heat source.

Inventors

• 👤 with respect to an invention of Fletcher James C. Administrator of the National Aeronautics and Space Administration
• 👤 Theodore R. Creel, Jr.
• 👤 Robert A. Jones
• 👤 Richard R. Corwin
• 👤 Joseph S. Kramer

Bibliographic Details