Etude par analogic electrique de differents types de tubes a gaz pulse: modelisation et experience

摘要

The main purpose of this paper is to explain the operation of pulse tubes refrigerators (PTR) by a network theory approach: the voltage and the current represent respectively the hydrodynamic parameters pressure P and mass flow rate m of the system. Each impedance is treated as a circuit of equivalent electrical element: resistance, capacitance or inductance. At the hot end of the PTR, different phase shift systems are modelled in the same way and could be compared, as the orifice pulse tube refrigerator (OPTR), the double inlet pulse tube refrigerator (DIPTR), the modified pulse tube refrigerator (MPTR) whose phasor is a moving piston at the hot end, the hybrid pulse tube refrigerator (HPTR) with a sequential orifice opening and the OPTR with inertance (IOPTR). By combining the network approach with the thermal analysis of the regenerator and the thermodynamic analysis of the tube it is possible to predict the energy balance at the cold end: extracted power, regenerator and tube losses and the influence of dead volumes. Different solutions were pointed out to treat this model. If the parameters are not sinusoidal the system might be treated at an order greater than 1. This modelling was used to design a miniature PTR operating at high frequency (20-50) Hz and pressure higher than 2 MPa, developed in collaboration with "Air Liquide" firm. The rotary or linear compressor used has 1 cm~3 swept-volume and is similar to that used on Stirling refrigerator and generate a quasi-sinusoidal pressure wave. Under a mean pressure of 3 MPa and a 27.5 Hz operating frequency, the lower temperature reached is 49 K with an available power of 1 W at 84 K, in a double inlet mode.