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Automatic control of NASA Langley's 0.3-meter cryogenic test facilityExperience during the past 6 years of operation of the 0.3-meter transonic cryogenic tunnel at the NASA Langley Research Center has shown that there are problems associated with efficient operation and control of cryogenic tunnels using manual control schemes. This is due to the high degree of process crosscoupling between the independent control variables (temperature, pressure, and fan drive speed) and the desired test condition (Mach number and Reynolds number). One problem has been the inability to maintain long-term accurate control of the test parameters. Additionally, the time required to change from one test condition to another has proven to be excessively long and much less efficient than desirable in terms of liquid nitrogen and electrical power usage. For these reasons, studies have been undertaken to: (1) develop and validate a mathematical model of the 0.3-meter cryogenic tunnel process, (2) utilize this model in a hybrid computer simulation to design temperature and pressure feedback control laws, and (3) evaluate the adequacy of these control schemes by analysis of closed-loop experimental data. This paper will present the results of these studies.
Document ID
Document Type
Conference Proceedings
Thibodeaux, J. J. (NASA Langley Research Center Hampton, Va., United States)
Balakrishna, S. (NASA Langley Research Center Hampton; Old Dominion University, Norfolk, Va., United States)
Date Acquired
August 10, 2013
Publication Date
January 1, 1980
Subject Category
Report/Patent Number
AIAA PAPER 80-0416
Meeting Information
Aerodynamic Testing Conference(Colorado Springs, CO)
Distribution Limits