Phase shift between gas velocity and pressure in an orifice pulse tube

(Received 15 July 1993, revised 8 October 1993, accepted 15 November 1993)

Abstract
In order to investigate how the phase shift between pressure P (t) and velocity of gas V (t) affects the net refrigeration power of an orifice pulse tube, we have recorded at the cold end of the regenerator, when the temperature is constant at 173 K and 259 K, the net refrigeration power and the two signals of dynamic pressure and velocity of gas. The phase shift is computed from FFT of the two signals. If we maintain the amplitude of pressure constant, the net refrigeration power varies as a function of the phase shift between pressure and velocity of gas.