THERMOACOUSTIC OSCILLATIONS IN CRYOGENICS .1. BASIC THEORY AND EXPERIMENTAL-VERIFICATION

Thermoacoustic oscillations are well known in cryogenics; in most cases they occur spontaneously and are undesired. Much work has been done to calculate this effect; with the final breakthrough achieved by Rott. In this paper, we present an extension to Rott's theory, which allows its application to more complicated geometries. Frequency, pressure amplitudes, power and heat flow can be determined with a moderate amount of computer calculations. Experimental verification has been made for a thermoacoustic heat engine, and good agreement has been found. Based on this theory and on experience with the experimental setup, possible applications of thermoacoustic oscillations as heat engines and as refrigerators will be discussed in part 2 of this paper. In part 3, guidelines for the correct design of cryogenic piping and of different dampers are given.