A fast gauge for energy flux density measurement

Abstract

Herein the design and characterization of a fast energy flux density gauge are described. The gauge is based on a thermoelectrical pair with the junction made of a thin layer of silver. High absorptivity is attained by an electrolytic deposit of platinum black on the silver coat. Dynamic calibration gives a response time below 100 fis. Computer methods to obtain the energy flux density from temperature-time history were evaluated: constant thermophysical properties of the thermoelectrical pair can be assumed in the ignition studies for which the gauge has been developed. The results of the tests performed with igniters of pelle ted boron/potassium nitrate and black powder, used in solid propellant ignition, are shown. The gauge developed can be applied to fast processes which require small response time. The gauge docs not need previous calibration, it is resistant to vibrations and accelerations, and at the same time it is small in size, economical, and easy to build. Changing the substrate or the thermoelectrical pair, the applications and ranges of temperature can be extended.FIGo 4. Photodiode and gauge signals showing the gauge response to a square wave of () = 8.5 ms.Energy flux density