パルス管冷凍機内の温度振動に及ぼす運転周波数の影響

抄録

This paper describes the influence of the driving frequency on the oscillating behavior of gas pressure and temperature inside a pulse tube refrigerator and the ultimate wall temperature at the cold end. Two types of pulse tube refrigerators, basic and orifice pulse tube refrigerators, are investigated. The length of the pulse tube is 300mm and its diameter is 13mm. The oscillation of the gas pressure and temperature at various points along the pulse tube refrigerator and the wall temperature distribution is obtained as a function of the driving frequency in the range from 1 to 18Hz. The gas pressure oscillation is quite similar at all measuring positions through the pulse tube for both types. However, the gas temperature oscillation differs from location to location along the pulse tube. The wall temperature at the cold end depends on the driving frequency and there exists an optimum range of the frequency within which the lowest value of the wall temperature is attained. It is found that typical frequencies in the optimum range are 3Hz for the basic type and 6Hz for the orifice type. The gas temperature oscillation at lower frequencies can be clearly distinguished from that at frequencies higher than the optimum values. Moreover, it is also shown that the differences in the oscillating behavior between both types are more noticeable at the lower driving frequencies.