Project Title:

Multi-Junction Thermocouple Gage

	  94-1	11.01	1992	B

	  Multi-Junction Thermocouple Gage

Abstract:

The study and development of solid and hybrid rocket motors often 
requires an accurate determination of regression rate of the 
burning or ablating surface. No fully satisfactory method has yet 
been devised to provide regression rate data in real time. This 
proposal suggests the development of a new type of sensor, based 
on the principal of a thermocouple, to serve as a real time 
regression rate sensor. The approach contemplated is to develop 
a multijunction thermocouple with extremely closely spaced 
junctions along its length. Such a sensor, embedded in a fuel 
grain of a hybrid motor, or in the ablative liner of a thrust 
chamber, or in the propellant grain of a solid rocket motor, 
would be able to indicate the time shifting profile of 
temperature in the material. And timing its sequential loss of 
signals from the series of junctions, would provide the 
incremental times required for the junctions to be exposed and 
destroyed. The time increments would indicate the rate of surface 
regression. The single sensor will provide: a) Surface regression 
rate, b) Material instantaneous temperature profile, c) 
Approximate surface temperature, d) Heat transfer rate, and e) 
Material temperature profile versus time.

The multijunction thermocouple's capability to provide several 
functions in a single sensor make it a useful item in both the 
aerospace and commercial industry communities. It can be 
developed rapidly and brought to market quickly, which makes it 
attractive from a commercialization standpoint. Rocket engine 
companies, chemical process companies, public utilities, foundrys 
and mineral processing plants are a few of the common industries 
who are likly customers for this sensor.

Key words

Orbital Technologies Corporation (ORBITEC)
402 Gammon Place, Suite 200
Madison, WI 53719